Re: [time-nuts] metric / English
Up till three or so years ago the VLA (Very Large Array radio telescope) was using a PDP 11/70. Most of the workstations were Sun Ultra 1 systems that were horribly outdated to a point where I had already sent mine to land fill a few years before. Now they have a spiffy Linux cluster on modern hardware, but the old system was as old as me. -Bob On Sat, Dec 17, 2011 at 6:44 PM, Jim Lux jim...@earthlink.net wrote: On 12/17/11 9:14 AM, J. Forster wrote: I suspect turret lathes are still used for shortish runs of some of the simpler parts, like bushings and similar parts. Not every shop looks like a NASA facility. Oddly, NASA facilities aren't necessarily the most modern or sophisticated. It takes an act of Congress to build a new building or make non-repair improvements. My office and lab at JPL is in an 3600 square meter 2 story semi-temporary building (161) built in 1954 (before NASA even existed). The frequency and timing lab is in building 298, an 1800 square meter building built in and was built in the 70s. Our big highbay spacecraft assembly building was built in 1961. (To be fair, there is a general plan to demolish a bunch of small buildings and replace them with larger buildings sometime in 2020-2030 time frame, if Congress approves). Much of the infrastructure at Johnson Spaceflight Center (and KSC, as well) was built for Apollo and followons in the 60s and early 70s We don't depreciate equipment, it's bought with capital expenditure or project funds, and then we pay for maintenance and calibration. A big project might buy a whole bunch of some piece of gear (e.g. HP8663A) which we will then use for the next 20-30 years (I just counted about 30 HP8663As in inventory.). I think we bought a whole pile of those 8663s in connection with upgrades for Voyager or maybe Cassini. As a result, we tend to keep gear forever.. Students coming on interviews are always amazed (and not necessarily in a good way). At least we've moved beyond slotted lines for the most part. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
Which works very well, but unlike all of the English thread combinations, you must keep the lathe's half-nuts engaged to the lead screw ALWAYS. That means when you reach the end of the thread, you must stop the lathe, and back it up to the beginning of the thread to make the next cut. With English threads the following rules exist for using the thread dial indicator: Even threads - engage half-nuts anytime Odd threads - engage half-nuts on any numbered line 1/2 threads - engage half-nuts on any odd numbered line 1/4 threads - engage half-nuts on the line you started with. Metric threads are miserable to cut on English lathes... and not much better on Metric lathes. Metric thread dial indicators are complicated and easy to get wrong devices. With English threads, you would have to work to get it wrong. -Chuck Harris Don Couch wrote: Hi, Brooke, To cut metric threads on an inch machine, I mesh the 127 tooth gear with the 100 tooth gear that came with my Sherline lathe threading attachment. Works great. Don Couch ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
On Sat, Dec 17, 2011 at 4:48 AM, Chuck Harris cfhar...@erols.com wrote: Which works very well, but unlike all of the English thread combinations, you must keep the lathe's half-nuts engaged to the lead screw ALWAYS. That means when you reach the end of the thread, you must stop the lathe, and back it up to the beginning of the thread to make the next cut. That method always works. But another might. There will always be some integer number of pitches that get you back exactly without error. But it might be say 5 inches back so there is almost always a way to run only forward you method might be the best. But are people still using these old machines for production work? Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
I suspect turret lathes are still used for shortish runs of some of the simpler parts, like bushings and similar parts. Not every shop looks like a NASA facility. -John == On Sat, Dec 17, 2011 at 4:48 AM, Chuck Harris cfhar...@erols.com wrote: Which works very well, but unlike all of the English thread combinations, you must keep the lathe's half-nuts engaged to the lead screw ALWAYS. That means when you reach the end of the thread, you must stop the lathe, and back it up to the beginning of the thread to make the next cut. That method always works. But another might. There will always be some integer number of pitches that get you back exactly without error. But it might be say 5 inches back so there is almost always a way to run only forward you method might be the best. But are people still using these old machines for production work? Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
Chris, You must be kidding! How old are you? Lee K9WRU - Original Message - From: Chris Albertson albertson.ch...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, December 17, 2011 11:00 AM Subject: Re: [time-nuts] metric / English But are people still using these old machines for production work? Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
On 12/17/11 9:14 AM, J. Forster wrote: I suspect turret lathes are still used for shortish runs of some of the simpler parts, like bushings and similar parts. Not every shop looks like a NASA facility. Oddly, NASA facilities aren't necessarily the most modern or sophisticated. It takes an act of Congress to build a new building or make non-repair improvements. My office and lab at JPL is in an 3600 square meter 2 story semi-temporary building (161) built in 1954 (before NASA even existed). The frequency and timing lab is in building 298, an 1800 square meter building built in and was built in the 70s. Our big highbay spacecraft assembly building was built in 1961. (To be fair, there is a general plan to demolish a bunch of small buildings and replace them with larger buildings sometime in 2020-2030 time frame, if Congress approves). Much of the infrastructure at Johnson Spaceflight Center (and KSC, as well) was built for Apollo and followons in the 60s and early 70s We don't depreciate equipment, it's bought with capital expenditure or project funds, and then we pay for maintenance and calibration. A big project might buy a whole bunch of some piece of gear (e.g. HP8663A) which we will then use for the next 20-30 years (I just counted about 30 HP8663As in inventory.). I think we bought a whole pile of those 8663s in connection with upgrades for Voyager or maybe Cassini. As a result, we tend to keep gear forever.. Students coming on interviews are always amazed (and not necessarily in a good way). At least we've moved beyond slotted lines for the most part. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
The manual machines are still in use for limited production runs, such as are used in prototype manufacture. Screw machines, and second op lathes see extensive use in manufacturing because they are quicker than CNC machines... that and very cheap to use. I use manual machines because it is quicker to whittle out a prototype chassis or do-dad on manual machines than it is to do a formal CAD drawing, and then work out the tool paths to do it on a CNC machine... and then find you have made it a mistake... wash rinse repeat... CNC machines are like printers. In theory they save time and materials, but in practice, they can burn time and waste materials like no human running a manual machine ever would. [As a tree farmer, who sells trees into pulp production, computers and printers have been a godsend. More trees go into paper production today then ever did before the advent of the paperless office.] -Chuck Harris Chris Albertson wrote: On Sat, Dec 17, 2011 at 4:48 AM, Chuck Harriscfhar...@erols.com wrote: Which works very well, but unlike all of the English thread combinations, you must keep the lathe's half-nuts engaged to the lead screw ALWAYS. That means when you reach the end of the thread, you must stop the lathe, and back it up to the beginning of the thread to make the next cut. That method always works. But another might. There will always be some integer number of pitches that get you back exactly without error. But it might be say 5 inches back so there is almost always a way to run only forward you method might be the best. But are people still using these old machines for production work? Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
You might want to consider the possibility that there is a whole world of manufacturing that does not deal with millions of a single item. And prototypes are not part of the process. When a product life might extend over ten years and you can expect to get orders for two or three per year (you know there are products that cost tens of millions of dollars) then high volume is of much less interest. Of course, a single part might require a five axis machine and then things are again different. I vividly recall one sales visit when I was only 35 or 40, and still hadn't learned anything, and found that a very familiar product was still being manufactured in a room with a dirt floor. Lee - Original Message - From: Chuck Harris cfhar...@erols.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Saturday, December 17, 2011 9:31 PM Subject: Re: [time-nuts] metric / English The manual machines are still in use for limited production runs, such as are used in prototype manufacture. Screw machines, and second op lathes see extensive use in manufacturing because they are quicker than CNC machines... that and very cheap to use. I use manual machines because it is quicker to whittle out a prototype chassis or do-dad on manual machines than it is to do a formal CAD drawing, and then work out the tool paths to do it on a CNC machine... and then find you have made it a mistake... wash rinse repeat... CNC machines are like printers. In theory they save time and materials, but in practice, they can burn time and waste materials like no human running a manual machine ever would. [As a tree farmer, who sells trees into pulp production, computers and printers have been a godsend. More trees go into paper production today then ever did before the advent of the paperless office.] -Chuck Harris Chris Albertson wrote: On Sat, Dec 17, 2011 at 4:48 AM, Chuck Harriscfhar...@erols.com wrote: Which works very well, but unlike all of the English thread combinations, you must keep the lathe's half-nuts engaged to the lead screw ALWAYS. That means when you reach the end of the thread, you must stop the lathe, and back it up to the beginning of the thread to make the next cut. That method always works. But another might. There will always be some integer number of pitches that get you back exactly without error. But it might be say 5 inches back so there is almost always a way to run only forward you method might be the best. But are people still using these old machines for production work? Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
Hi Don: Sure converting lengths is easy and I have metric, English and weird taps and dies, but how do you turn metric threads? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html Don Couch wrote: The idea that conversion to metric would require replacing all of the machine tools (lathes, mills, etc) is a myth. Any U.S. machine shop has walls and toolboxes covered in conversion charts, converting drill, screw, wire, sheet sizes from one crazy measurement to another. One single additonal conversion chart, inch to metric, and you can keep using your inch machines on metric projects. My mill has inch lead screws. I added a low cost digital readout with a little button to show inch or millimeter movements, and now I do everything in metric. No problem. Don Couch --- On Thu, 12/15/11, Dan Kemppainend...@irtelemetrics.com wrote: From: Dan Kemppainend...@irtelemetrics.com Subject: Re: [time-nuts] time-nuts Digest, Vol 89, Issue 51 To: time-nuts@febo.com Date: Thursday, December 15, 2011, 10:29 AM On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote: It's not like metric is totally absent. We drink 2 liter cokes and defend ourselves with 9mm pistols. Our cars use mostly metric parts. Even ham radio operators, arguably the most jingoistic and set in the past bunch around, get on the 80, 40, and 20 METER bands. I agree with you, and funnily enough the rest of the NATO world uses 7.62mm and 5.56mm rifles. (Both were originally based on standard inch sized rifle cartridges designed in the US) The problem in converting to metric would require replacing a lot of tools. For example Mills, lathes, and other machining tools and measurement devices are expensive, and last for decades. I doubt many of the small tool shops around here could afford it.It's a great idea to standardize in theory, but in practice it becomes difficult. Maybe the whole world should standardize our language. We could all switch to Spanish or Latin or Chinese to speak with so we could all talk with each other. That would probably be more helpful to me on a daily basis, than having to switch measurement systems. While we're on the subject, let me throw time back into the mix. We use months and days for scheduling projects. Meanwhile some of our counterparts use calendar weeks. This is much more difficult to convert between than inch and mm. When is CW 36??? There I threw some wood on the fire too! Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
Which ones? Some time ago I was setting up to turn a Metric and discovered that there where a Japanese Metric standard for the thread as well as a German Metric standard both of which where slightly different from the standard Metric threadd that was I wanted to cut. Cheers, Graham ve3gtc -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: December 16, 2011 11:49 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] metric / English Hi Don: Sure converting lengths is easy and I have metric, English and weird taps and dies, but how do you turn metric threads? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html Don Couch wrote: The idea that conversion to metric would require replacing all of the machine tools (lathes, mills, etc) is a myth. Any U.S. machine shop has walls and toolboxes covered in conversion charts, converting drill, screw, wire, sheet sizes from one crazy measurement to another. One single additonal conversion chart, inch to metric, and you can keep using your inch machines on metric projects. My mill has inch lead screws. I added a low cost digital readout with a little button to show inch or millimeter movements, and now I do everything in metric. No problem. Don Couch --- On Thu, 12/15/11, Dan Kemppainend...@irtelemetrics.com wrote: From: Dan Kemppainend...@irtelemetrics.com Subject: Re: [time-nuts] time-nuts Digest, Vol 89, Issue 51 To: time-nuts@febo.com Date: Thursday, December 15, 2011, 10:29 AM On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote: It's not like metric is totally absent. We drink 2 liter cokes and defend ourselves with 9mm pistols. Our cars use mostly metric parts. Even ham radio operators, arguably the most jingoistic and set in the past bunch around, get on the 80, 40, and 20 METER bands. I agree with you, and funnily enough the rest of the NATO world uses 7.62mm and 5.56mm rifles. (Both were originally based on standard inch sized rifle cartridges designed in the US) The problem in converting to metric would require replacing a lot of tools. For example Mills, lathes, and other machining tools and measurement devices are expensive, and last for decades. I doubt many of the small tool shops around here could afford it.It's a great idea to standardize in theory, but in practice it becomes difficult. Maybe the whole world should standardize our language. We could all switch to Spanish or Latin or Chinese to speak with so we could all talk with each other. That would probably be more helpful to me on a daily basis, than having to switch measurement systems. While we're on the subject, let me throw time back into the mix. We use months and days for scheduling projects. Meanwhile some of our counterparts use calendar weeks. This is much more difficult to convert between than inch and mm. When is CW 36??? There I threw some wood on the fire too! Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
With a metric tap die set? :-) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Brooke Clarke Sent: 16 December 2011 16:48 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] metric / English Hi Don: Sure converting lengths is easy and I have metric, English and weird taps and dies, but how do you turn metric threads? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html Don Couch wrote: The idea that conversion to metric would require replacing all of the machine tools (lathes, mills, etc) is a myth. Any U.S. machine shop has walls and toolboxes covered in conversion charts, converting drill, screw, wire, sheet sizes from one crazy measurement to another. One single additonal conversion chart, inch to metric, and you can keep using your inch machines on metric projects. My mill has inch lead screws. I added a low cost digital readout with a little button to show inch or millimeter movements, and now I do everything in metric. No problem. Don Couch --- On Thu, 12/15/11, Dan Kemppainend...@irtelemetrics.com wrote: From: Dan Kemppainend...@irtelemetrics.com Subject: Re: [time-nuts] time-nuts Digest, Vol 89, Issue 51 To: time-nuts@febo.com Date: Thursday, December 15, 2011, 10:29 AM On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote: It's not like metric is totally absent. We drink 2 liter cokes and defend ourselves with 9mm pistols. Our cars use mostly metric parts. Even ham radio operators, arguably the most jingoistic and set in the past bunch around, get on the 80, 40, and 20 METER bands. I agree with you, and funnily enough the rest of the NATO world uses 7.62mm and 5.56mm rifles. (Both were originally based on standard inch sized rifle cartridges designed in the US) The problem in converting to metric would require replacing a lot of tools. For example Mills, lathes, and other machining tools and measurement devices are expensive, and last for decades. I doubt many of the small tool shops around here could afford it.It's a great idea to standardize in theory, but in practice it becomes difficult. Maybe the whole world should standardize our language. We could all switch to Spanish or Latin or Chinese to speak with so we could all talk with each other. That would probably be more helpful to me on a daily basis, than having to switch measurement systems. While we're on the subject, let me throw time back into the mix. We use months and days for scheduling projects. Meanwhile some of our counterparts use calendar weeks. This is much more difficult to convert between than inch and mm. When is CW 36??? There I threw some wood on the fire too! Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
Not that hard, actually. My 1984-vintage lathe has an inch lead screw, but the quick-change box that drives the leadscrew will do all of the inch and most metric threads directly. The few weird metric pitches are accommodated by changing two gears on the input side of the QC box. I suppose that at some very small level, there is some error in the metric threads produced (and I've never bothered to calculate it for my lathe) but it's a VERY small error that has never been an issue for me. 73, geo - n4ua On Fri, Dec 16, 2011 at 11:48 AM, Brooke Clarke bro...@pacific.net wrote: Hi Don: Sure converting lengths is easy and I have metric, English and weird taps and dies, but how do you turn metric threads? Have Fun, Brooke Clarke http://www.PRC68.com http://www.**end2partygovernment.com/**Brooke4Congress.htmlhttp://www.end2partygovernment.com/Brooke4Congress.html Don Couch wrote: The idea that conversion to metric would require replacing all of the machine tools (lathes, mills, etc) is a myth. Any U.S. machine shop has walls and toolboxes covered in conversion charts, converting drill, screw, wire, sheet sizes from one crazy measurement to another. One single additonal conversion chart, inch to metric, and you can keep using your inch machines on metric projects. My mill has inch lead screws. I added a low cost digital readout with a little button to show inch or millimeter movements, and now I do everything in metric. No problem. Don Couch --- On Thu, 12/15/11, Dan Kemppainendan@irtelemetrics.**comd...@irtelemetrics.com wrote: From: Dan Kemppainendan@irtelemetrics.**com d...@irtelemetrics.com Subject: Re: [time-nuts] time-nuts Digest, Vol 89, Issue 51 To: time-nuts@febo.com Date: Thursday, December 15, 2011, 10:29 AM On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote: It's not like metric is totally absent. We drink 2 liter cokes and defend ourselves with 9mm pistols. Our cars use mostly metric parts. Even ham radio operators, arguably the most jingoistic and set in the past bunch around, get on the 80, 40, and 20 METER bands. I agree with you, and funnily enough the rest of the NATO world uses 7.62mm and 5.56mm rifles. (Both were originally based on standard inch sized rifle cartridges designed in the US) The problem in converting to metric would require replacing a lot of tools. For example Mills, lathes, and other machining tools and measurement devices are expensive, and last for decades. I doubt many of the small tool shops around here could afford it.It's a great idea to standardize in theory, but in practice it becomes difficult. Maybe the whole world should standardize our language. We could all switch to Spanish or Latin or Chinese to speak with so we could all talk with each other. That would probably be more helpful to me on a daily basis, than having to switch measurement systems. While we're on the subject, let me throw time back into the mix. We use months and days for scheduling projects. Meanwhile some of our counterparts use calendar weeks. This is much more difficult to convert between than inch and mm. When is CW 36??? There I threw some wood on the fire too! Dan __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
On Fri, Dec 16, 2011 at 8:48 AM, Brooke Clarke bro...@pacific.net wrote: Hi Don: Sure converting lengths is easy and I have metric, English and weird taps and dies, but how do you turn metric threads? How would you cut 40 tpi or 24 tpi? You put in the correct gears to drive the lead screw so the tool moves at the desired rate To cut metric threads they use a gear with the correct ratio to drive the lead screw. Yes if the lead screw is 1/8 inch the drive gears will have some odd ratio but it works. The reason it works is because back in 1959 they re-defined the inch to be an EXACTLY 25.4mm. From then on gears with integer number of teeth will do the metric/imperial conversion perfectly. I think I said a while back that any machine shop that can't figure this out has likely already gone out of business. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
You use the change gears in a ratio of 127:50 (254:100) -John == Hi Don: Sure converting lengths is easy and I have metric, English and weird taps and dies, but how do you turn metric threads? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html Don Couch wrote: The idea that conversion to metric would require replacing all of the machine tools (lathes, mills, etc) is a myth. Any U.S. machine shop has walls and toolboxes covered in conversion charts, converting drill, screw, wire, sheet sizes from one crazy measurement to another. One single additonal conversion chart, inch to metric, and you can keep using your inch machines on metric projects. My mill has inch lead screws. I added a low cost digital readout with a little button to show inch or millimeter movements, and now I do everything in metric. No problem. Don Couch --- On Thu, 12/15/11, Dan Kemppainend...@irtelemetrics.com wrote: From: Dan Kemppainend...@irtelemetrics.com Subject: Re: [time-nuts] time-nuts Digest, Vol 89, Issue 51 To: time-nuts@febo.com Date: Thursday, December 15, 2011, 10:29 AM On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote: It's not like metric is totally absent. We drink 2 liter cokes and defend ourselves with 9mm pistols. Our cars use mostly metric parts. Even ham radio operators, arguably the most jingoistic and set in the past bunch around, get on the 80, 40, and 20 METER bands. I agree with you, and funnily enough the rest of the NATO world uses 7.62mm and 5.56mm rifles. (Both were originally based on standard inch sized rifle cartridges designed in the US) The problem in converting to metric would require replacing a lot of tools. For example Mills, lathes, and other machining tools and measurement devices are expensive, and last for decades. I doubt many of the small tool shops around here could afford it.It's a great idea to standardize in theory, but in practice it becomes difficult. Maybe the whole world should standardize our language. We could all switch to Spanish or Latin or Chinese to speak with so we could all talk with each other. That would probably be more helpful to me on a daily basis, than having to switch measurement systems. While we're on the subject, let me throw time back into the mix. We use months and days for scheduling projects. Meanwhile some of our counterparts use calendar weeks. This is much more difficult to convert between than inch and mm. When is CW 36??? There I threw some wood on the fire too! Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
There is no error with the change gears. The ratio of inches to centimeters is exactly 1:2.54 or 100:254 or 50:127. It is often done with a train of 3 gear pairs to get the center-to-center shaft spacing right. -John = Not that hard, actually. My 1984-vintage lathe has an inch lead screw, but the quick-change box that drives the leadscrew will do all of the inch and most metric threads directly. The few weird metric pitches are accommodated by changing two gears on the input side of the QC box. I suppose that at some very small level, there is some error in the metric threads produced (and I've never bothered to calculate it for my lathe) but it's a VERY small error that has never been an issue for me. 73, geo - n4ua On Fri, Dec 16, 2011 at 11:48 AM, Brooke Clarke bro...@pacific.net wrote: Hi Don: Sure converting lengths is easy and I have metric, English and weird taps and dies, but how do you turn metric threads? Have Fun, Brooke Clarke http://www.PRC68.com http://www.**end2partygovernment.com/**Brooke4Congress.htmlhttp://www.end2partygovernment.com/Brooke4Congress.html Don Couch wrote: The idea that conversion to metric would require replacing all of the machine tools (lathes, mills, etc) is a myth. Any U.S. machine shop has walls and toolboxes covered in conversion charts, converting drill, screw, wire, sheet sizes from one crazy measurement to another. One single additonal conversion chart, inch to metric, and you can keep using your inch machines on metric projects. My mill has inch lead screws. I added a low cost digital readout with a little button to show inch or millimeter movements, and now I do everything in metric. No problem. Don Couch --- On Thu, 12/15/11, Dan Kemppainendan@irtelemetrics.**comd...@irtelemetrics.com wrote: From: Dan Kemppainendan@irtelemetrics.**com d...@irtelemetrics.com Subject: Re: [time-nuts] time-nuts Digest, Vol 89, Issue 51 To: time-nuts@febo.com Date: Thursday, December 15, 2011, 10:29 AM On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote: It's not like metric is totally absent. We drink 2 liter cokes and defend ourselves with 9mm pistols. Our cars use mostly metric parts. Even ham radio operators, arguably the most jingoistic and set in the past bunch around, get on the 80, 40, and 20 METER bands. I agree with you, and funnily enough the rest of the NATO world uses 7.62mm and 5.56mm rifles. (Both were originally based on standard inch sized rifle cartridges designed in the US) The problem in converting to metric would require replacing a lot of tools. For example Mills, lathes, and other machining tools and measurement devices are expensive, and last for decades. I doubt many of the small tool shops around here could afford it.It's a great idea to standardize in theory, but in practice it becomes difficult. Maybe the whole world should standardize our language. We could all switch to Spanish or Latin or Chinese to speak with so we could all talk with each other. That would probably be more helpful to me on a daily basis, than having to switch measurement systems. While we're on the subject, let me throw time back into the mix. We use months and days for scheduling projects. Meanwhile some of our counterparts use calendar weeks. This is much more difficult to convert between than inch and mm. When is CW 36??? There I threw some wood on the fire too! Dan __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
On Fri, Dec 16, 2011 at 9:45 AM, George Dubovsky n4ua...@gmail.com wrote: . I I... suppose that at some very small level, there is some error in the metric threads produced (and I've never bothered to calculate it for my lathe) but it's a VERY small error that has never been an issue for me. No error. They fixed that problem 50 years ago by simply redefining all Imperial lengths to be exact integer ratios of the meter. the inch is _exactly_ 25.4mm. Ages ago 25.4 was only a close approximation but since 1959 it has been exact. So in a small way we already converted to the metric system 50 years ago. Miles, yards, feet, inches all are legally defined for the last 50 years by their relation to the meter. And as I said those relations are NOT approximations, they are definitions. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
I have small British lathe (Myford) with a 1/8 inch leadscrew, and a 127 tooth gear is inconveniently large. By examining the ratio of every gear for every thread required (with a simple basic program) I found a solution within 50 parts per million for all metric threads. The wierdest threads are not metric but imperial, 19 threads per inch? Incidently the Whitworth threads, with included angle of 55 degrees and coarse pitch are ideal for soft materials like Plexiglass (perspex, methyl methacrylate). cheers, Neville Michie On 17/12/2011, at 5:48 AM, J. Forster wrote: There is no error with the change gears. The ratio of inches to centimeters is exactly 1:2.54 or 100:254 or 50:127. It is often done with a train of 3 gear pairs to get the center-to-center shaft spacing right. -John = Not that hard, actually. My 1984-vintage lathe has an inch lead screw, but the quick-change box that drives the leadscrew will do all of the inch and most metric threads directly. The few weird metric pitches are accommodated by changing two gears on the input side of the QC box. I suppose that at some very small level, there is some error in the metric threads produced (and I've never bothered to calculate it for my lathe) but it's a VERY small error that has never been an issue for me. 73, geo - n4ua On Fri, Dec 16, 2011 at 11:48 AM, Brooke Clarke bro...@pacific.net wrote: Hi Don: Sure converting lengths is easy and I have metric, English and weird taps and dies, but how do you turn metric threads? Have Fun, Brooke Clarke http://www.PRC68.com http://www.**end2partygovernment.com/ **Brooke4Congress.htmlhttp://www.end2partygovernment.com/ Brooke4Congress.html Don Couch wrote: The idea that conversion to metric would require replacing all of the machine tools (lathes, mills, etc) is a myth. Any U.S. machine shop has walls and toolboxes covered in conversion charts, converting drill, screw, wire, sheet sizes from one crazy measurement to another. One single additonal conversion chart, inch to metric, and you can keep using your inch machines on metric projects. My mill has inch lead screws. I added a low cost digital readout with a little button to show inch or millimeter movements, and now I do everything in metric. No problem. Don Couch --- On Thu, 12/15/11, Dan Kemppainendan@irtelemetrics.**comd...@irtelemetrics.com wrote: From: Dan Kemppainendan@irtelemetrics.**com d...@irtelemetrics.com Subject: Re: [time-nuts] time-nuts Digest, Vol 89, Issue 51 To: time-nuts@febo.com Date: Thursday, December 15, 2011, 10:29 AM On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote: It's not like metric is totally absent. We drink 2 liter cokes and defend ourselves with 9mm pistols. Our cars use mostly metric parts. Even ham radio operators, arguably the most jingoistic and set in the past bunch around, get on the 80, 40, and 20 METER bands. I agree with you, and funnily enough the rest of the NATO world uses 7.62mm and 5.56mm rifles. (Both were originally based on standard inch sized rifle cartridges designed in the US) The problem in converting to metric would require replacing a lot of tools. For example Mills, lathes, and other machining tools and measurement devices are expensive, and last for decades. I doubt many of the small tool shops around here could afford it.It's a great idea to standardize in theory, but in practice it becomes difficult. Maybe the whole world should standardize our language. We could all switch to Spanish or Latin or Chinese to speak with so we could all talk with each other. That would probably be more helpful to me on a daily basis, than having to switch measurement systems. While we're on the subject, let me throw time back into the mix. We use months and days for scheduling projects. Meanwhile some of our counterparts use calendar weeks. This is much more difficult to convert between than inch and mm. When is CW 36??? There I threw some wood on the fire too! Dan __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/ listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/ listinfo/time-nuts and follow the instructions there. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://www.febo.com/cgi-bin/mailman/ listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
Re: [time-nuts] metric / English
Hi, Brooke, To cut metric threads on an inch machine, I mesh the 127 tooth gear with the 100 tooth gear that came with my Sherline lathe threading attachment. Works great. Don Couch --- On Fri, 12/16/11, Brooke Clarke bro...@pacific.net wrote: From: Brooke Clarke bro...@pacific.net Subject: Re: [time-nuts] metric / English To: Discussion of precise time and frequency measurement time-nuts@febo.com Date: Friday, December 16, 2011, 9:48 AM Hi Don: Sure converting lengths is easy and I have metric, English and weird taps and dies, but how do you turn metric threads? Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html Don Couch wrote: The idea that conversion to metric would require replacing all of the machine tools (lathes, mills, etc) is a myth. Any U.S. machine shop has walls and toolboxes covered in conversion charts, converting drill, screw, wire, sheet sizes from one crazy measurement to another. One single additonal conversion chart, inch to metric, and you can keep using your inch machines on metric projects. My mill has inch lead screws. I added a low cost digital readout with a little button to show inch or millimeter movements, and now I do everything in metric. No problem. Don Couch --- On Thu, 12/15/11, Dan Kemppainend...@irtelemetrics.com wrote: From: Dan Kemppainend...@irtelemetrics.com Subject: Re: [time-nuts] time-nuts Digest, Vol 89, Issue 51 To: time-nuts@febo.com Date: Thursday, December 15, 2011, 10:29 AM On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote: It's not like metric is totally absent. We drink 2 liter cokes and defend ourselves with 9mm pistols. Our cars use mostly metric parts. Even ham radio operators, arguably the most jingoistic and set in the past bunch around, get on the 80, 40, and 20 METER bands. I agree with you, and funnily enough the rest of the NATO world uses 7.62mm and 5.56mm rifles. (Both were originally based on standard inch sized rifle cartridges designed in the US) The problem in converting to metric would require replacing a lot of tools. For example Mills, lathes, and other machining tools and measurement devices are expensive, and last for decades. I doubt many of the small tool shops around here could afford it.It's a great idea to standardize in theory, but in practice it becomes difficult. Maybe the whole world should standardize our language. We could all switch to Spanish or Latin or Chinese to speak with so we could all talk with each other. That would probably be more helpful to me on a daily basis, than having to switch measurement systems. While we're on the subject, let me throw time back into the mix. We use months and days for scheduling projects. Meanwhile some of our counterparts use calendar weeks. This is much more difficult to convert between than inch and mm. When is CW 36??? There I threw some wood on the fire too! Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] metric / English
Hi Chris: Yes. In hospitals they are measuring your height in feet and inches, but your weight is in kg (6' 1 120 kg). Sort of like tire sizes which use inches for the wheel diameter and mm for the section width (P215/65R15 - 215mm section width, 15 rim diameter). Even more interesting than the metric/English idea is that my local shop (all CNC) has a no extra cost tolerance that's ten times tighter than the no extra charge tolerance (+/-500 Millionths) an experienced machinist can hold (+/-5 mils) and they have coordinate measuring equipment to back up the much tighter tolerances you can get for the extra charge. A related story is that back in the 1960s I was designing microwave parts, many of which were made on a lathe. There was a local shop that had chucker lathes (our company shop also had one) but this local shop would always come in below the in house and competitive bids. These all used 5C collets. http://www.prc68.com/I/Lathe.shtml http://www.prc68.com/I/DrillPress.shtml#5C It turned out the the low bid shop had a screw machine in the back room that was kept a secret for maybe a year or two. The chuckers were really not being used to make parts. But now screw machines have been replaced by fancier CNC machines like the 12 Axis CNC Mill Turn Centers. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Brooke4Congress.html Chris Albertson wrote: On Thu, Dec 15, 2011 at 9:29 AM, Dan Kemppainend...@irtelemetrics.com wrote: On 12/14/2011 3:59 PM, time-nuts-requ...@febo.com wrote: It's not like metric is totally absent. We drink 2 liter cokes and defend ourselves with 9mm pistols. Our cars use mostly metric parts. Even ham radio operators, arguably the most jingoistic and set in the past bunch around, get on the 80, 40, and 20 METER bands. I agree with you, and funnily enough the rest of the NATO world uses 7.62mm and 5.56mm rifles. (Both were originally based on standard inch sized rifle cartridges designed in the US) The problem in converting to metric would require replacing a lot of tools. For example Mills, lathes, and other machining tools and measurement devices are expensive, and last for decades. Can you point one even ONE machine shop in the US that can make metric parts? Those guys would have gone out of business years ago. Also how many are still using hand cranks and reading veneer scales? Even small one man ships are using CNC now. The US is slowly converting. It will take a long time. Even now if you go to Home Depot and look at plywood you see the better (non construction) grades sold in even millimeters with the inches being some odd number of 32nds approximation. This will slowly creep into more and more products. So the debate is silly. If the US should convert??? No. the only question is how fast are we converting and when will we be fully converted. Not even if this will happen, it will. Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
