Re: [Emc-users] Why are there different sizes of centre drills?
I think if you have a large machine it won't spin fast enough and it will be to easy to break the tiny drill point. If you have a tiny lathe the chuck might be too small for large diameter center drill. John Figie On Sat, May 11, 2024, 8:19 AM Stuart Stevenson wrote: > Hi, > Sounds like you guys are talking about the tool known as a combination > center drill and countersink. > Most CNC operations use a spot drill as a precision starting guide for the > drill point entry. > I don't know about the precision differences between the two styles but if > you really require a close tolerance hole position you should use a more > involved process than just a spot (or center) drill and drill. Drills walk. > The main reason to use a spot drill is time. A spot drill is faster. > > regards > Stuart > > On Sat, May 11, 2024 at 1:50 AM > wrote: > > > On 2024-05-11 03:32, andy pugh wrote: > > > That's it. really. Why? A large-diameter one with a small drill point > > > could > > > make all the sizes. as far as I am aware the drilled hole is > > > irrelevant. I > > > suppose it might have mattered as a reservoir for the white lead in the > > > days of solid centres. > > > > Interesting question! > > The pilot (parallel) drill creates a hole for the very tip of the mating > > centre. If the drill had to cut the exact shape of the conical tip of > > the female hole, it would struggle to have proper cutting edges and > > still make the true cone. > > You are right that the conical end on the body of a large centre drill > > (ignoring the parallel tip) could cut all sizes of cone. But there might > > be some reasons for the different sizes: > > > > 1. very small centres would enter the parallel drilled hole, but miss > > the conical part. I have just been trying to clean some small center > > holes in a clockmaking tool designed to support the ends of small > > diameter clock shaft pivots which run between two female centres. Those > > pivots would completely miss the conical part of the female hole which > > had anything but the smallest parallel section at the end. > > > > 2. for male centres which will take a decent load, the end needs to bear > > inside a large (deep) female hole, so a large drill can be used here, > > especially when pushing drilling feeds and speeds. The flip-side of > > that is that allowing the body of the centre drill to set the final > > diameter provides a small amount of parallel recess at the outer end of > > the centre, which will foul a centre and hold it off the female cone. > > Centre drills do exist to create 'protected' centres with a larger > > parallel recess just at the entry to the female cone. Those drills have > > a short stepped-out section of cutting edge of larger diameter than the > > largest end of the female cone. > > > > 3. In pre-CNC days, the best way to set the size of a hole would be to > > have a drill of the correct diameter(s) mounted in a turret with stops. > > The operator then would not need to think, but could just pull the > > lever. Aside from the problem in (1), you could, of course, set the stop > > to make a large drill create a small diameter centre. Which makes CNC > > an obvious advantage, of course. > > > > Marcus > > > > > > ___ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > -- > Addressee is the intended audience. > If you are not the addressee then my consent is not given for you to read > this email furthermore it is my wish you would close this without saving or > reading, and cease and desist from saving or opening my private > correspondence. > Thank you for honoring my wish. > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Why are there different sizes of centre drills?
Hi, Sounds like you guys are talking about the tool known as a combination center drill and countersink. Most CNC operations use a spot drill as a precision starting guide for the drill point entry. I don't know about the precision differences between the two styles but if you really require a close tolerance hole position you should use a more involved process than just a spot (or center) drill and drill. Drills walk. The main reason to use a spot drill is time. A spot drill is faster. regards Stuart On Sat, May 11, 2024 at 1:50 AM wrote: > On 2024-05-11 03:32, andy pugh wrote: > > That's it. really. Why? A large-diameter one with a small drill point > > could > > make all the sizes. as far as I am aware the drilled hole is > > irrelevant. I > > suppose it might have mattered as a reservoir for the white lead in the > > days of solid centres. > > Interesting question! > The pilot (parallel) drill creates a hole for the very tip of the mating > centre. If the drill had to cut the exact shape of the conical tip of > the female hole, it would struggle to have proper cutting edges and > still make the true cone. > You are right that the conical end on the body of a large centre drill > (ignoring the parallel tip) could cut all sizes of cone. But there might > be some reasons for the different sizes: > > 1. very small centres would enter the parallel drilled hole, but miss > the conical part. I have just been trying to clean some small center > holes in a clockmaking tool designed to support the ends of small > diameter clock shaft pivots which run between two female centres. Those > pivots would completely miss the conical part of the female hole which > had anything but the smallest parallel section at the end. > > 2. for male centres which will take a decent load, the end needs to bear > inside a large (deep) female hole, so a large drill can be used here, > especially when pushing drilling feeds and speeds. The flip-side of > that is that allowing the body of the centre drill to set the final > diameter provides a small amount of parallel recess at the outer end of > the centre, which will foul a centre and hold it off the female cone. > Centre drills do exist to create 'protected' centres with a larger > parallel recess just at the entry to the female cone. Those drills have > a short stepped-out section of cutting edge of larger diameter than the > largest end of the female cone. > > 3. In pre-CNC days, the best way to set the size of a hole would be to > have a drill of the correct diameter(s) mounted in a turret with stops. > The operator then would not need to think, but could just pull the > lever. Aside from the problem in (1), you could, of course, set the stop > to make a large drill create a small diameter centre. Which makes CNC > an obvious advantage, of course. > > Marcus > > > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Addressee is the intended audience. If you are not the addressee then my consent is not given for you to read this email furthermore it is my wish you would close this without saving or reading, and cease and desist from saving or opening my private correspondence. Thank you for honoring my wish. ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] cloning hard drive
On 5/10/24 19:44, Chris Albertson wrote: On May 10, 2024, at 9:49 AM, gene heskett wrote: On 5/10/24 11:25, Chris Albertson wrote: Rsync will copy data at the file system level.I think the OP wants to copy the partition tables and boot sector.But rsync can copy across a network and is a decent way to make a backup of your data. Clonzilla loks like it can work. I’ve always used “dd” because it is a two letter command and very easy to rember the exact spelling, and it just works. Clonzilla might be better for people who find it hard to type in long complex commands like “dd” and prefer a menu-based system. All good advice. Choose your favorite. The one I miss is the one that can take an arm64 install, with all the additions to do a job, and back it up over the network to a file that only the total used on that arm64 system. one that can then be copied to a fresh u-sd card of much greater capacity, and which will then on first boot, expand the partitions to use all of the new u-sd cards capacity. I've been using 64G cards and had had no losses. 16G cards are big enough but have a lifetime of around a year. I have some 128G I'll use for the next install. Raspberry Pi5 can use PCIe storage, no SD card is needed. Eventually, we will all stop using SD cards for system drives. I keep wanting to reconfigure my Pi4 to boot off the network with no SD card installed. The Pi3’s networking was too slow for this and the Pi5 does not need it. I might never get around to it. So what I do today is a compromise. I install Linux from an image file. I never store my data on the SD card. data is NFS mounted from the network server. This also means the data is always available on my other computers. I never have to move it. and if an SD card dies, nothing is lost. I never have to backup an SD card. Interesting concept. When I get time to concentrate on it. I'll probably pester you for details. Thanks Chris. ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] cloning hard drive
On 5/10/24 14:27, Linden wrote: I have used clonezilla and DD for both back up and restore. Some where I have an interactive bash scripted I wrote for using DD. In the past when going from a small drive to a new larger drive the most reliable way I found was to use DD to clone and move the data and the use gparted to expand the partitions. Not the most elegant solution but has worked for me in the past. Just a thought might be worth looking at. I've considered that myself, but it feels sorta kludgy to me. But done in that sequence it should work. I'm in the middle of a different $$project ATM so it will be at least a month before I get to that. Thanks. On May 10, 2024 9:49:31 a.m. PDT, gene heskett wrote: On 5/10/24 11:25, Chris Albertson wrote: Rsync will copy data at the file system level.I think the OP wants to copy the partition tables and boot sector.But rsync can copy across a network and is a decent way to make a backup of your data. Clonzilla loks like it can work. I’ve always used “dd” because it is a two letter command and very easy to rember the exact spelling, and it just works. Clonzilla might be better for people who find it hard to type in long complex commands like “dd” and prefer a menu-based system. All good advice. Choose your favorite. The one I miss is the one that can take an arm64 install, with all the additions to do a job, and back it up over the network to a file that only the total used on that arm64 system. one that can then be copied to a fresh u-sd card of much greater capacity, and which will then on first boot, expand the partitions to use all of the new u-sd cards capacity. I've been using 64G cards and had had no losses. 16G cards are big enough but have a lifetime of around a year. I have some 128G I'll use for the next install. The theory is, the more surplus capacity the card has, the better the cards own software can maintain it. Power usage is about 25 watts total for the pi and nonitor when the lathe is powered down, so that rpi4 is never turned off, it even has a small ups that holds it up well while the kohler 20kw is starting, a black time of around 8 seconds. So I'm looking for a dd like command that will do that over my local network. cd / && sudo du -h says there is 6.2G in actual use. But there is a 256G buildbot drive not currently mounted but about 70% full, so that total would be considerably more. So what utility can make me a bootable image thats only 6.5G that I can store here, dd to a new card that will boot that pi and expand the file system? And come up capable of running linuxcnc with all the stuff I've written in the last decade. That is the $64 question. That seems like the ideal backup system for all the architectures here. And 1, 2T SSD could hold it all. On May 10, 2024, at 4:03 AM, gene heskett wrote: On 5/10/24 06:11, andrew beck wrote: hey everyone a bit off topic here i have my main laptop that i want to clone the hard drive on it for a identical laptop for a backup this is used for running the linuxcnc machines and programming drawing etc anyway just want to know what software people prefer for disk cloning i have never done it before and i'm sure someone on here is a expert on it cheers andrew rsync can do that but please read the man page carefully. It can bite you just as easily as it can help you. I use it, but will not call myself an expert. Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett, CET. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis ___ Emc-users mailing list
Re: [Emc-users] Why are there different sizes of centre drills?
On 2024-05-11 03:32, andy pugh wrote: That's it. really. Why? A large-diameter one with a small drill point could make all the sizes. as far as I am aware the drilled hole is irrelevant. I suppose it might have mattered as a reservoir for the white lead in the days of solid centres. Interesting question! The pilot (parallel) drill creates a hole for the very tip of the mating centre. If the drill had to cut the exact shape of the conical tip of the female hole, it would struggle to have proper cutting edges and still make the true cone. You are right that the conical end on the body of a large centre drill (ignoring the parallel tip) could cut all sizes of cone. But there might be some reasons for the different sizes: 1. very small centres would enter the parallel drilled hole, but miss the conical part. I have just been trying to clean some small center holes in a clockmaking tool designed to support the ends of small diameter clock shaft pivots which run between two female centres. Those pivots would completely miss the conical part of the female hole which had anything but the smallest parallel section at the end. 2. for male centres which will take a decent load, the end needs to bear inside a large (deep) female hole, so a large drill can be used here, especially when pushing drilling feeds and speeds. The flip-side of that is that allowing the body of the centre drill to set the final diameter provides a small amount of parallel recess at the outer end of the centre, which will foul a centre and hold it off the female cone. Centre drills do exist to create 'protected' centres with a larger parallel recess just at the entry to the female cone. Those drills have a short stepped-out section of cutting edge of larger diameter than the largest end of the female cone. 3. In pre-CNC days, the best way to set the size of a hole would be to have a drill of the correct diameter(s) mounted in a turret with stops. The operator then would not need to think, but could just pull the lever. Aside from the problem in (1), you could, of course, set the stop to make a large drill create a small diameter centre. Which makes CNC an obvious advantage, of course. Marcus ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
