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Shanks and stem junction

Posted: Tue Jun 09, 2009 10:37 am
by Briarfox
I'm working on a bent apple and in my hast I forgot to face off the shank. I went back and chucked it up as best I could but there is about a hair length of daylight thats driving me nuts. Any suggestions on how to remedy this? I usually don't forget to face my shanks :(

I was thinking about turning down some abs to the mortise diameter and putting some sand paper between and twisting.

Any other ideas?

Thanks

Posted: Tue Jun 09, 2009 10:59 am
by Olivier
Your idea sounds right to me. I can only suggest you glue the sandpaper onto something thin and hard and then carefully drill a hole through it the size of the tenon. Slip it over the tenon with the sandpaper facing the shank, press it in tightly and then rotate the disk. If you are afraid of damaging the tenon or stem you could use a different piece of ABS. Perhaps you could save this amongst your tools for when/if it happens again :wink:

Posted: Tue Jun 09, 2009 11:40 am
by Briarfox
Olivier wrote:Your idea sounds right to me. I can only suggest you glue the sandpaper onto something thin and hard and then carefully drill a hole through it the size of the tenon. Slip it over the tenon with the sandpaper facing the shank, press it in tightly and then rotate the disk. If you are afraid of damaging the tenon or stem you could use a different piece of ABS. Perhaps you could save this amongst your tools for when/if it happens again :wink:
I'm using sticky backed sandpaper. I plan on turning down a new piece of abs since I don't want to ruin the stem. But there has to be a better way.

How do you shape first drill second guys do this?

Posted: Tue Jun 09, 2009 12:33 pm
by KurtHuhn
Utilizing a pin gauge that fits snugly in the mortis.

What I do:
- Chuck the pin gauge in the lathe
- put the pipe on the pin gauge
- spin the pipe only as fast as I need to get a smooth cut
- using a facing tool, or LH cutting tool, take light cuts until it's perfect

There are probably other methods...

Posted: Tue Jun 09, 2009 12:58 pm
by Briarfox
Kurt that sounds like an awesome method. But pardon my ignorance. What is a pin gauge? Alos how do you keep the pipe from flying off?

Is a pin gauge just a dowel that is used to find whole diameter?

Posted: Tue Jun 09, 2009 1:37 pm
by kbadkar
Briarfox wrote:Kurt that sounds like an awesome method. But pardon my ignorance. What is a pin gauge? Alos how do you keep the pipe from flying off?

Is a pin gauge just a dowel that is used to find whole diameter?
A pin gauge is like a metal dowel that is precisely sized to the hundreds or even thousandths of an inch. Get a few right around the size of your mortise and you will find one of them will be a perfect friction fit.

Search for pin gauge in your browser or check McMaster-Carr, Harbor Freight, or any major industrial tooling supply shop.

Posted: Tue Jun 09, 2009 1:37 pm
by KurtHuhn
A pin (or plug) gauge is a steel cylinder, machined to close tolerances of a specific size - usually in thousandths of an inch. You can get a set of .251 to .500 from Enco for under $40 in tolerances good enough for our purposes.

You use one that gives a snug fit, and the friction itself is usually good enough to keep it from sliding off providing you're careful and take light cuts. You can also use a live center in the tailstock to support the pipe and keep it in place.

Posted: Tue Jun 09, 2009 1:41 pm
by kbadkar
Sorry to snipe your response, Kurt.

Oh, and Briarfox, try using the other end of the drill bit that you used to drill the mortise. If you drilled cleanly (cleared chips), the blank end of the bit should hold your stummel fairly snugly. If not, try wrapping a single layer of thin tape on the bit and twist it in the mortise gently.

Posted: Tue Jun 09, 2009 2:38 pm
by Briarfox
Once again you guys are a god send. Thanks again.

Posted: Tue Jun 09, 2009 2:59 pm
by KurtHuhn
kbadkar wrote:Sorry to snipe your response, Kurt.
Looks like we responded at precisely the same time. :)

--Kurt
(who is having a lazy day and goofing off on the Internet)

Posted: Tue Jun 09, 2009 11:04 pm
by Sasquatch
Am I completely wacked to do this with a bit of gentle file work?

Posted: Tue Jun 09, 2009 11:08 pm
by RadDavis
Sasquatch wrote:Am I completely wacked to do this with a bit of gentle file work?
If it works for you, why not?

You can do it with sandpaper and a flat surface too.

A pin gauge set just makes it sooooo much easier.

Rad

Posted: Wed Jun 10, 2009 12:24 am
by Sasquatch
RadDavis wrote: If it works for you, why not?

You can do it with sandpaper and a flat surface too.

A pin gauge set just makes it sooooo much easier.

Rad
Well, I get good results, but then, I also max out around $1.50/hour wages making pipes, so maybe there's something to be said for a faster method. :D :shock:

Posted: Wed Jun 10, 2009 10:09 am
by KurtHuhn
RadDavis wrote: You can do it with sandpaper and a flat surface too.
I use this method when there's just a hair's gap that needs levelling, or if I need to sand the shank face for some reason. I use a granite machinists plate that I got a while back, though a piece of thick glass would work just as well also. Or the bed of a wood lathe is usually pretty flat - I've done that before too.
A pin gauge set just makes it sooooo much easier.
Right after I read Todd's first post on pin gauges (a few years ago I think), I went and bought a set. It's worth every penny.

Posted: Wed Jun 10, 2009 10:39 am
by Briarfox
So how fast do you turn it? I would image that it could fly off pretty easy so your suggestion of using the tailstock sounds like a must.

Posted: Wed Jun 10, 2009 10:52 am
by KurtHuhn
Max speed on my metal lathe is about 750 RPM, so it isn't really an issue. Using a pin gauge that fits snugly, the danger of it flying off is almost none at that speed. My wood lathe, however, spins much faster (500RPM lowest speed), and there is a slight danger of it rattling off - which is why I use the metal lathe to do this now that I have one.

Posted: Wed Jun 10, 2009 2:00 pm
by FredS
KurtHuhn wrote:
RadDavis wrote: You can do it with sandpaper and a flat surface too.
I use this method when there's just a hair's gap that needs levelling, or if I need to sand the shank face for some reason. I use a granite machinists plate that I got a while back, though a piece of thick glass would work just as well also. Or the bed of a wood lathe is usually pretty flat - I've done that before too.
That's how I do it too. Put the stem in the shank and use a piece of .001" metal shim stock to find the "high" (tight) spot in the joint. The I use a pencil to draw a circle on the face of the shank and put a line on the "high" side. Then I draw it across sandpaper on a granite plate, putting just a bit more pressure on the "high" side. Keep making passes until your mark disappears all the way around, and test the fit again.

If the gap is more than about .005" I chuck my mortise drill bit upside down/backwards in the drill press and push the stummel up onto it. Then turn it on at a medium speed (900 rpm) and use a file to square it up.

Posted: Wed Jun 10, 2009 4:01 pm
by ToddJohnson
Briarfox wrote:So how fast do you turn it? I would image that it could fly off pretty easy so your suggestion of using the tailstock sounds like a must.
~550 RPM's and no, the tailstock is not necessary unless you have a very small, light, or unstable lathe.

TJ

Posted: Thu Jun 18, 2009 4:15 pm
by Briarfox
Thanks again guys. The Pin Gauge's came in and they work perfectly!