On Wednesday 11 May 2016 02:22:41 Peter Blodow wrote: > Gene, > cast iron is easy to cut, mill and turn because it contains lots of > carbon, better known as graphite which is a natural solid lubricant. > Using water in addition, if any, is merely for cooling and carrying > away the debris. However, if the casting has been cooled very rapidly, > it may be surface hardened (this is used for industrial purposes, > too). You won't get a scratch on such "hard cast iron" with ordinary > tools. So it may be that diamond cutting is useful for getting through > the surface, the rest could be cut with any old steel tool.
And far less precisely. I left about .1" to be able to make this the exact height to put the tip of a 5/16" cutting tool as exactly at the center height, minus a 1/32" brass shim under the tool in a stock 4 cornered tool holder which is far more rigid than any QC holder in the sizes suitable for use on such a small lathe. I also intend to hollow cut both top and bottom faces by a thou or so, so that the mating surfaces are as widely contacted as possible when the 10mm holddown bolt for the tool holder is brought to full tension, and that the bottom will be in as wide a contact as is practical. The bottom is mated to the crossfeed with a loose plug, flanged to be pulled up against the flange by a pair of 6mm cap screws that one normally loosens to adjust the compound angle. But I see that in addition to the tool holder mount being moved to the right and back, that I will also need to allow more clearance to a large workpiece by removing at least another 1/2" from the front for large pieces as I am backed out about as far as the crossfeed can, and quite a ways out on the compound, and the workpiece is nibbling on the compounds base. IOW, selling this lathe as a 7" is pure marketing BS as its real limit is about 4". Only with a lantern post tool holder would it ever clear 5". And my attempts to build one of those haven't been too successful, mainly due to lack of vertical space for the rocker key and socket. I may make 2 of these, with the 2nd about a half inch thinner just so a lantern post could be made to work. > I would have used one of my angle grinders with a grinding disc for > steel and cut down that cast iron piece in a matter of minutes. It all > depends on the right bonding material of the grains. > > By the way; tell an old non-American, what is the idea of this lawyer > biz you mentioned? > > Peter Probably the most famous quote from the writings of William Shakespear. I find in my dealings that they have studied the law, often to find the exceptions to the rule of common sense, so deeply that no common sense survives in their world view. That turns the great majority of them into leeches on society. Leeches are NOT productive members of any specie. > Am 10.05.2016 23:57, schrieb Gene Heskett: > > On Tuesday 10 May 2016 15:41:57 andy pugh wrote: > >> On 10 May 2016 at 14:28, Roland Jollivet > >> <roland.jolli...@gmail.com> > > > > wrote: > >>> I once watched a contractor dry cut rebar with a diamond blade > >>> using a cut-off saw. I wanted to tell him you can't do that, > >> > >> http://www.husqvarna.com/us/construction/products/diamond-blades-fo > >>r-p ower-cutters/di5-ductile-iron-blade/ > > > > If I can put yet another oar in this water, it seems to me that > > Husqvarna et all, is far more interested in selling you another > > blade at quite a nice profit margin than in doing a job correctly. > > > > Diamond, spinning at those speeds, will shatter from impact, and if > > not adequately cooled, will get hot enough to ablate/evaporate the > > diamond, both of which will result in the premature destruction of > > the blades ability to cut anything. > > > > Unfortunately, when you are paying the person who needs to cut such > > by the hour, it quickly becomes expedient to buy the fresh blade to > > replace the one destroyed by the pressure to "get the job done". It > > becomes a C.O.D.B. > > > > By running it wet, you can somewhat alleviate the heat that > > evaporates the diamond. But note the "somewhat" because the heating > > is localized, confined to the actual contact of that grain of > > diamond with the material being cut, and at the rim speeds of a > > modern power saw, there is 100x more air at the contact interface > > than water as its carried into the slot being cut by the rapidity of > > the rim, which itself is busily throwing that water away from the > > blade and generally makeing a huge mess of the environment up to 15 > > or 20 feet away. > > > > At nominally 400 revs on a 10" wheel, the impact shock that shatters > > the diamond is reduced by 10x, reducing the cutting degradation rate > > by an estimated 10,000%. And if not pushing the blade, but just > > letting the diamond carry away the cutting dust its making, the > > heating will also be reduced. In making those two cuts thru a solid > > casting about 4.25" in diameter, I watched the rim temp with an IR > > thermometer, and never saw it exceed 120F at about 3/8" in from the > > blades edge. It appeared the actual edge of the blade was running > > 15F cooler. > > > > Yes, it took a long time to do those 2 cuts. Had I been physically > > able to attend to the mill full time, about a day a cut. But that > > blade can do that, at that cut rate, probably another 100 times. > > > > Running that slow and easy, wet or dry has relatively little effect > > on blade longevity because there is not enough heat, or a high > > enough impact shock to damage the diamond. > > > > All of this seduction of the canine could have been alleviated had I > > been able to back the clock up to about 1948 when an uncle of mine > > landed a contract to cut the mounting bosses off an eyeglass lens > > makers cast iron forms so his forms would be usable in a newer > > machine. My uncle built the first abrasive cutup saw I ever saw, > > and he didn't have any lawyers telling him what he could not do. In > > '48, the abrasive wheels came in 10 or 11", you wrapped them on a > > shield of steel about 1/4" thick to catch the shrapnel as the > > recommended rpms for those wheels was pretty close to 9500. So he > > first used a pulley ratio that gave about 7500, but it wasn't fast > > enough to easily start the fire. So he went to town and got the > > next smaller pulley, which gave it almost exactly 10 grand. > > > > Bringing the wheel to the casting, it only took 3 or 4 seconds to > > start the fire, and it literally fell thru the 1.25" square block of > > cast they were cutting off in another 2 or 3 seconds. He blew up > > one wheel in cutting about 200 of them off that way. > > > > But can I buy an abrasive saw that will cut like that today? Not > > no, but hell no, at least not without putting 5 grand or more into > > it. The best OTC saw turns a 14" wheel about 4 grand, and it cannot > > get the fire started in a 1/2x2" bar of cold roll without 3 or 4 > > minutes of leaning heavily on the blade just to get the fire > > started. The damned lawyers and bean counters have caused the wheel > > speed to be reduced (14" wheels are rated for 6500) and the shrapnel > > catchers are a piece of Prince Albert can. Scary. > > > > Modern tech, by the time the lawyers get thru with it, sucks. > > > > My Dad worked in '52-55, in the tool & die room at a place in Des > > Moines called Solar Aircraft, that was making jet engine parts out > > of SS and titanium. Somebody shaved the JIT schedule and they ran > > out of bandsaw blades on Thursday, with the next shipment due in > > Monday next. While those blades did have teeth, the teeth were > > intended more for carrying air into the cut to carry away the molten > > metal as they actually cut by friction heating. Daddy picked up a > > steel shipping strap, welded it up at the length needed for the > > bandsaw. It worked fairly well so he made about 40 more with each > > one lasting about an hour. That kept production going until the new > > blades arrived. And he got a nice little present for saving those 2 > > days downtime. > > > > First, we kill ALL the lawyers, still sounds like a heck of a good > > idea... > > > > Cheers, Gene Heskett > > --- > Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. > http://www.avast.com > > > ---------------------------------------------------------------------- >-------- Mobile security can be enabling, not merely restricting. > Employees who bring their own devices (BYOD) to work are irked by the > imposition of MDM restrictions. Mobile Device Manager Plus allows you > to control only the apps on BYO-devices by containerizing them, > leaving personal data untouched! > https://ad.doubleclick.net/ddm/clk/304595813;131938128;j > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Mobile security can be enabling, not merely restricting. Employees who bring their own devices (BYOD) to work are irked by the imposition of MDM restrictions. Mobile Device Manager Plus allows you to control only the apps on BYO-devices by containerizing them, leaving personal data untouched! https://ad.doubleclick.net/ddm/clk/304595813;131938128;j _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
