On 11.05.18 01:25, Gene Heskett wrote: > On Thursday 10 May 2018 22:23:56 Erik Christiansen wrote: > > But, whoa. I'm also not fully across the need for bore adjustment. As > > taps are ground from a few stock sizes, only those few sizes of tap > > hat bore are needed. While I found a drill close enough for one size, > > and bored the other, if I had to make a bunch of the latter, I'd > > probably make up a D-bit reamer, and keep it with the tap hat kit. > > Looking at my tap collection, I'd guess it will take not less than 10 > different drills to bore the thru holes to fit the tap shanks. I have a > very mixed origin tap collection, And the metric stuff all is Chinese, > quality from junk to very good.
Hmmm. Then I'd bore the odd ones to size ... when I needed 'em. Just keep enough brass sleeves to hand, drilled out enough for the small boring bar to go in. > And I'm trying to dream up a way to mill a square in the rear, where the > square but of the tap will be, and since I have one of those kilowatt > induction heaters, figure out how to pour a lower melting point alloy of > some sort to fix the square tap butt into the square in the rear of the > brass holder, as thats a bunch easier than all that drilling and tapping > for set screws. High silver alloy solder comes to mind as its some > pretty tough stuff. But would that heat, maybe 850-900F kill the tap? Urrgh. Wet flannel around the business end of the tap ought to protect against the brutality inflicted on the other end, but there are better ways to skin a cat than with a flamethrower. How's this size up?: Radially slot the top end of the tap hat body to provide two internal flats to grip the tap square, then drill/bore from the other end to take the tap. If you overshoot, then the middle of each flat will go, but the outer third or so on each side will remain unless the square end of the tap has been made unnaturally small. But hold on, what keeps the tap captive then? I'm sticking with the grubscrews. > If I do the set screw thing, I'll need them in 2mm to 6mm, or maybe even > 8mm for the biggest ones. Well, you could MIG tack weld the top of the taps into steel tap hats - that wouldn't conduct much heat to the other end, but that's rough treatment too. A box or three of grubscrews off fleabay won't add up to much cost. The last boxful I bought was M3 to M10, IIRC. You might do better buying plastic bags of each size, for quantity. > Thats not counting a 20 kg bag of 1.5" to 4"ers for pipe I found while > cleaning up the old home place after Dee's brother died. None in good > shape, broken teeth etc. He worked for one of the local gas companies > as a mech at a pumping station. Rigid tapping with the 4"er might challenge the machine ... not least getting the job under the spindle, I figure. ... > I didn't like the looks of the sky when I left to get a loaf of bread and > a paper and something I could nuke for our dinner, and had to sit out > the worst of it trapped in my pickup in the grocery store parking lot. > And the same back at the house. I got soaked in the 50 feet plus opening > the back door of the king cab to retrieve the sacks, run for the house. > 30 minutes later, full sunshine again. Crazy weather. Seems to be more of that about these days. Forecast for tomorrow is one month's rain in a day for Gippsland. I'm staying here. (They need it - desperately, for stockwater and domestic rainwater tanks. Too late for pastures, though.) > Stay warm Erik, it should be getting toward keeping the wood stove > crackling in your neck of the woods. Its been up as high as 89F here > already. The hills here are smaller than yours (I'm only at 600' altitude), but with 40F less than at your place, the heater's earning its keep already. Erik ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
