I am trying to build a rotating pedistal that locks in place with a pin through holes in a concentric ring. I need the pin to be tapered so that it will enter the hole easily but hold the ring with no slop. There will be a lot of side pressure on the pin so the taper angle can't be so large as to force it out of the hole but OTOH, it can't be so shallow that it will bind like a Morse.
Is there a standard locking pin angle? I don't want to waste a lot of TGP rod experimenting.
Glenn Ashmore snipped-for-privacy@mindspring.com
wrt placement-holding pin
Dunno. Why not a straight pin with a front end chamfer? If there's slop in the parts, a self-releasing taper may not cure that.
If you get such a tapered pin, then you have to get tooling, etc. to make the female tapers. With a straight pin, it's just drilling for the fit.
I don't (amateur here) know of any standard self-releasing tapers for stuff you build. (Of course there are standard self-releasing tapers for machinery--but those are locked in alternatively to the taper.)
Frank Morrison
Yep. The handbook says that all the ANSI self-releasing tapers are 3.5 inches of diameter per foot.
To plug one of my favorite series of books - Guy Lautard's 'Bedside Reader' series has a great explanation of releasing/non releasing tapers. Buy them all for the information that is in one of them. Worth it. Standard disclaimer..... Ken. (sitting here in Honduras wishing I had brought them with me)
Well, you don't say how big the tapered hole is to be, but one way to bore a taper is to mount the workpiece in a lathe chuck, put a boring tool in the toolpost, slew the toolpost around to your angle, and bore it.
Grant
Glenn Ashmore wrote:
Hey Glenn,
This is what cutter grinders (Quorn, Stent, Deckel come to mind immediately) are for. To create "D" style cutters with the required angle. 1/2" solid carbide isn't that expensive.
Take acre.
Brian Laws>Thanks, that was what I needed. About 16.5º included angle. Now I just
If you can't follow Grant's suggestion and bore it (which is the best solution), then this is a job for a D-bit reamer, which you can make easily on a lathe.
I'd step-drill the hole in a few steps first to clean out the bulk of the material first. Do you know about making D-bits? You turn the shape (taper, in this case) on your lathe (I'd use O1 drill rod), then grind off half of the tip on a grinder. If you have a surface grinder, that's perfect. If not, you can do it well enough on a bench grinder. I've made a lot of D-bits on one and they work. I've even made a couple of rifle chambering reamers this way, and they were successful.
For a reamer, you may want to cut just a bit less than half of the reamer-end away, so you'll have a slight negative rake on the cutting edge. That makes it harder to cut but the reamer will follow the hole better.
There has to be a discussion and photos of D-bits somewhere on the Web.
Would you not have to remove just less than half for as deep as you needed to ream rather than just at the tip?
Ted
Yes, but fortunately Glenn knew about D-bits and I didn't have to make the effort to explain it better. I'm lazy today.
Ed Huntress
There ya go!
In general, I think it would depend on the materials, surface condition or finish, and presence (or not) of lubrication. I seem to recall that if the tangent of the half-angle is greater than the coefficient of friction then the taper is self-releasing. I might have read that in one of Guy Lautard's books.
"Ed Huntress" snipped-for-privacy@optonline.net
It does get a bit more complex with a self-releasing tapered pin. The OP seems intent on making a tapered pin, however. FM
Probably should have explaned the whole project first. This is a 4 position rotating grinding/polishing stand I am building. A spring loaded peddle pulls the pin out of the locking ring to move to the next position. I wanted the rotating part to lock stifly in place so that I wouldn't get any sway when pushing against a wheel. getting the pivot and bearing surfaces close was not a problem but the lock was a big question
The 3.5" taper and the D bit did it. Still have to mount the motors and mandrels tomorrow but the base is nice and stable.
Ed Huntress wrote:
Have something to add? Share your thoughts — no account required.
Ask the community — no account required