Gene, M7 screws are as rare as white raven since this thread is only printed in fine italics the DIN book. The only place I know of them being used is for fastening the cooler fan of some Renault vehicles, but merely in left handed version. No kidden. The French are supposed to use M7 more frequently, like in constructing basement storage shelves, but, as the saying goes, cooks in hell are english and mechanics in hell are french... There is not much good with M7 anyway since the threads are the same pitch as M6, so their holding force will be about equal to M6, just making bolts heavier. Wonder how in the world you got to own M7 cutting tools, I know nobody who ever even saw one? (I myself have a left handed one, by buying a wholesale box from the flea market). Moreover: If you managed to strip the M6 threads out, you won't gain much by replacing them with M7 since thread depth is just the same.
Use M8 and you're out of trouble, 25% more depth (if there is sufficient spindle diameter). By the way: why don't you just cut those spindle threads by hand, anyway, why bothering your itsi bitsi machine and PSU with it, or did I miss something? On the other hand, owning a lathe, why don't you make your own bolts to any size you want? I often have to make strange, e.g. imperial threads and others, like camera adapters (using pure unobtainium, as you say). It's easy. Greetings Peter Am 08.05.2016 05:49, schrieb Gene Heskett: > Greetings all; > > Trying to hold a 10" diamond saw blade yesterday, tight enough to keep it > from slipping, I striped out the 6mm threads in my arbor. > > So today I bored it gently out to around .230" or 15/64's and re-tapped > that to 7mm x1.0. It wasn't until I was cleaning that up that I > realized I had not seen any 7mm x1.0 screws on my side of the planet. > So I assume that I may as well redo it for an 8mm screw tomorrow. > > But that will be loads of fun because with the 7mm tap in the chuck, I > had to keep asking for a smaller peck per stroke because even in low > gear, and the current limit in Jon's servo amp set to limit at about 15 > amps, 150% drive for that motors nameplate, I was raising the divider > that determined the additional stroke per peck until it was taking at > least 7 or 8 pecks to tap one additional mm deeper. Combine that with > the tap I was using have a longer that normal nose taper, I hit the > bottom of the hole and that locked the spindle so I'm standing there, > noting the spindle had stopped and jon's servo amp was singing as it > overload regulated. Stopped lcnc, loosened the chuck to release the > tap, ran the head up 6" or so, and unscrewed the tap from the hole. > Threads look great, but I suspect there is not a 7mm cap screw about in > these here parts. Pure unobtainium comes to mind for the alloy. :) > > So, just out of curiosity, are 7mm bolts really that hard to find, or am > I looking in the wrong local stores? > > NAPA perhaps? Pricy there though. Seems metric in the label makes them > an additional $2 a bolt or nut. Been there, done that. Should have > gotten a free t-shirt for the price I paid for a 6 pack of 8mm self > lockers. Bah. > > Home Depot, up in Bridgeport, 26 miles up the Super-Pot-Hole, aka I-79 > has the best stock ATM, but I cannot recall seeing any 7's. 8's I can > probably get locally at Tractor Supply. In a decent alloy even. > > I also think my 8mm tap is a lot sharper than the black oxide finished > 7mm is, so maybe I can get by driving it with the mill. We'll find out > tommorrow. > > Thanks everybody. > > Cheers, Gene Heskett --- Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. http://www.avast.com ------------------------------------------------------------------------------ Find and fix application performance issues faster with Applications Manager Applications Manager provides deep performance insights into multiple tiers of your business applications. It resolves application problems quickly and reduces your MTTR. Get your free trial! https://ad.doubleclick.net/ddm/clk/302982198;130105516;z _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
