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tetramachine wrote: ↑Mon Jan 08, 2018 4:47 pmOne drill I've found is called a Coredrill, not a Coring Drill. This has generally 4 flutes, and needs a large hole to follow as it does not have a point.
Had to look that up. Here's one. You can see the large diameter of the web on the end.
I use mt2 in my drill press and the lathe tailstock, so it's worth more investment to me; but I found big bits are not all that expensive. German made HSS at $5-10.
Where? Chagas steel in Portimao Portugal, but I doubt that will help anyone here!
They do seem to only come in a specific range of sizes for each MT size.
I have an adapter mt2 to mt3, and drill up to 30mm [1-1/4"]
I put a 25mm mt3 bit in the lathe and cut it down to mt2, after setting the compound just as Harold wrote.
Setup was finicky [for me anyway], but it came out ok.
I also made an mt2 boring bar while it was set.
I find that MT bits work fine as long as everything is straight and smooth. As soon as there's and side pressure [uncentered pilot hole, asymmetrical bit grind] or juddering, they pop out and everything becomes really annoying.
Check the female tapers in your tailstock and drill press. Morse tapers should not release as long as there is compression. You should be able to seat the bit by hand and not be able to pull it out again.
I bought a few core drills when I was using the old Sebastian and May lathe but haven't used them much lately. They do work well and drill straight. In fact I had sharpened a couple with the General Tool drill sharpener and they came out very useful. That drill sharpener works better for me with large drills. OOPs tangential remark again.
The core drills work very well for opening up holes.
--earlgo
Before you do anything, you must do something else first. - Washington's principle.
No no. If you look deeper at the tang, it was "tapered". Dear engineers worked this out a long time ago. They were estimating use in production climate where Morse tapered drills were being replaced frequently. A perfect tang in a perfect socket ( the sockets were tapered to fit ) That was the starting point. Slam them in and don't slip under low pressure. The increasing pressure seats the "tang" further while the taper is more engaged. Delicate balance of grinding and again, we may not see that.
Okay, okay not going there again about sawing off a tang. It is over. modifying the tang so it can either penetrate or be ejected from the tailstock. That is old news. It comes down to "fit" of the taper collapse to the item.
I see a few videos and every one has everything. Cool for that. Drill press no good, get another one- oh get a really big one. Impressive, you know. They can mess that up as well as the old one. They know everything and much about selfies. Hey they are all cool with their tattoos like they served in the joint instead of the military Hey they are putting stuff together. Okay then, cut out the frame of a classic and "mock" it for its 1939 engineering.
Hey dudes. Go to a National cemetery once in awhile.
Is it about "style" ? Sure it is. We have seen this but not exactly. They tried. Where are they now. ? Eye candy yet different. The sugarless type which causes a laxative effect.