Pin/Key chuck - anyone familiar?

[Mike Minto]

I think I saw a post here, or an advertisement for this item - it's called a 'pin', or 'key' chuck - like a bar of metal with a section removed, and a piece of metal which lays in the 'gap'. When a drilled wood blank is placed over the metal bar, it is twisted about half-way around, and sort of locks in, holding onto the shaft of the 'chuck'. Anyone know where I can buy one, or plans would be better - would like to gain info on this tool and maybe make one. Thanks.

[Brian Effinger]

Is this (http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=packard&Product_Code=110106&Category_Code=) what you mean?

[Wally Wenzel]

Mike, I have one it is 1"round with a flat spot on one sspot you lay a 1/8 " dia. pin on the flat , drill a 1" hole in your wood, push it on the pin and twist the wood and locked on. I have it for over 20 years it is part of the precision combination chuck which came from the UK. I believe this is older than the chucks we have now, but it works good. Wally

[Jason Clark2]

http://bestwoodtools.stores.yahoo.net/pinchspty.html

Jason

[Mike Minto]

Is this (http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=packard&Product_Code=110106&Category_Code=) what you mean?


Brian, yes, that is what I'm talking about. Thanks - had seen that ad, but forgotten about it. I'm wanting one in 3/4 and 1/2 inch bores for turning game calls. Thanks.

[Leo Van Der Loo]

The big screw chuck is a better chuck than the pin chuck, specially in wet and soft wood, and the screw chuck is mounted in the regular wood chuck were the jaws will help to hold and steady the blank, that's my experience anyway (and you aren't loosing that little pin every time you try to mount or take off the blank).

[Mike Minto]

Leo, I'm looking for something to mount a 'tube' of wood for turning game calls on; a screw chuck would not fit that bill. Thanks, though :).

[Leo Van Der Loo]

OK that does make a difference, should work for that, just be carefull as the thin wall could be split with the pin jamming.

[Marvin Hasenak]

Do a search on Ebay for "call mandrel", there are several makers selling them on there.

[Mike Minto]

OK that does make a difference, should work for that, just be carefull as the thin wall could be split with the pin jamming.


Good point!

[John Terefenko]

Mike

I use them alot and make my own. I bought a set of these transfer punches from Harbor Freight when they are on sale for $7 http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=3577

Any size I need I just grind a flat spot using my bench grinder and then pick an apropriate finish nail and cut it down to the size I need. Stick the end in my collet chuck and you are good to go. They work great. And cheap.

[Mike Minto]

Thanks for all the links and ideas. I'll probably just buy some cold rolled steel and use my grinder to make the chucks; will need to get bigger collets for my Beall chuck, though - don't think I can grind a MT2 and get it centered :(. Anyone know a way to do that, without a metal lathe? And the locking mechanism on these kind of 'chucks' - is it just that the metal pin cams against two points on the wood blank, or just how does it hold?

[Richard Coers]

I make pin chucks in hard maple all the time. I have some that I first turn down a tenon that will fit a Beall chuck, but others start from a blank of wood in a 4 jaw scroll chuck. Besides the cost benefit, I like the wood chucks because I can clean up the end of the cylinder and not be afraid of hitting steel with the chisel. Take your time with a skew, and you can turn a very accurate cylinder. Keep a sanding block around with 80 grit if you aren't too confident of your abilities.

[M Toupin]

Tdon't think I can grind a MT2 and get it centered :(. Anyone know a way to do that, without a metal lathe?

A 3/8" MT2 end mill holder is what I use. A 3/8" piece of rod fits inside and you can change it out as needed. I use the same setup for bottle stoppers with a threaded rod inserted. Be sure to use a draw bar so it doesn't come loose if you're not supporting the outboard end.

http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=947771&PMAKA=210-1122

Mike

[Grant Wilkinson]

Mike: Like some others here, I make my own. You can use transfer punches, any round stock or even bolts. The pin can be just a finishing nail with the head cut off. When you file the flat spot on the rod, you want it to be straight across and just deep enought that the nail, lying the centre, ends up being the same diameter as the rest of the rod. When you turn it, the nail moves to a shallower spot on the flat spot and locks there. The contact point is the length of the nail. Clear as mud?

[Mike Minto]

Mike: Like some others here, I make my own. You can use transfer punches, any round stock or even bolts. The pin can be just a finishing nail with the head cut off. When you file the flat spot on the rod, you want it to be straight across and just deep enought that the nail, lying the centre, ends up being the same diameter as the rest of the rod. When you turn it, the nail moves to a shallower spot on the flat spot and locks there. The contact point is the length of the nail. Clear as mud?


Guys, thanks again for all the great info. Grant - so the 'flat' you grind onto the round stock should be slanted slightly? I'm assuming this, else how would it have a 'shallow' to lock onto :confused:. Richard - I like the Hard Maple idea - may try that, too!

[Marvin Hasenak]

Forget about using a nail or something for the pin, go to a welder supply house and get some 1/8" steel rods used for acetylene welding. They are uniform in size and you will lose a lot of them over time. Not a case of might lose, you will lose them. You can cut these with a hacksaw.

The flat spot needs to be a couple of thousandths more than the 1/8", .125 deep in to the mandrel, so .1252 should be about right. I usually check when I am at .125 then file it the rest of the way. But I use a milling machine, so stop at about .1000 and file it from there. You will need to do this to get the spot as flat as possible so when the mandrel is rotated the pin will roll and then catch on the wood.

It should look like this without the steel that is removed on each end of where tha call blank will sit. You will also need to machine a 60 degree dimple in the end for the tailstock, you can do this with a center drill, available from Harbor Freight or any machine shop supply house.

http://i224.photobucket.com/albums/dd161/CatclawCreek/Metal%20Shop/CALLPHOTOS4-27-07172.jpg

[Grant Wilkinson]

Mike: I just knew that my explanation was no good. You don't need to slant the flat spot. You just file straight across the bolt or rod. You end up with a shallow spot because you are filing straight across a curve. One of the guys here showed a pic of one. It shows you much better than my words do. When you file straight across, the "void" is deeper in the middle since that is where the top of the curve of the bolt is. At the perimeters, it is shallower. At those points, the pin will be higher than the outside of the bolt, and therefore bigger than the hole that you've put it in. That's what makes it hold.

[Mike Minto]

How sure is it a 'center drill' will bore a centered hole without wobbling? Is there something special about the way they work?

[Marvin Hasenak]

The center drill is short, just a little bit over an inch in length, and a tough piece of steel. I haven't had an wobble on me.

[Mike Minto]

The center drill is short, just a little bit over an inch in length, and a tough piece of steel. I haven't had an wobble on me.

Ah, I see...so if I chuck up a metal bar, the centering is up to me - then the drill will do it's thing. I'm just afraid, with a wood lathe (not the precision of a metal lathe - that is way beyond me, I think) that I'll be the limiting factor and drill the dimple a little off center. But, I will try, and report back. Wonder how a call mandrel will work being held at the headstock end only - as long as it's not too long, should be OK, I hope :o.