Pin Chuck Help Needed...

[Matt Owen]

I've never used a pin chuck, and I don't fully understand how one works. Does anyone know where I can get some information on how it works, along with detailed pictures of it.

I'm wanting to make a small one, one that fits a hole about 1/4" in diameter. I have access to a machine shop, so I should be able to do this if I can figure out what they look like, and how they work. Any information would be appreciated. Thanks,

Matt

 

[Ken Grunke]

Matt,
Find a nail or any metal pin with a diameter of 1/4 to 1/3 of the 1/4" shaft's diameter. Grind, file, or mill a flat on the shaft whose depth is equal to the pin's diameter, or just a hair less. The pin sits on the flat as the workpiece is mounted on the spindle shaft, then wedges itself in the hole as you give the workpiece about 1/4 of a turn clockwise.

I've made these in sizes from 1/4" to 1" and the depth of flat doesn't seem to be critical, the 3/8" and the 1" both use a 1/8" pin. There's probably an optimum ratio between the pin size and shaft size somewhere if you want to get technical about it.

On the first ones I made I milled the flat all the way off the end and on later ones, I left an unmilled area at the end. Seems that gives a little better alignment, and the pin comes out instead of staying in the hole.

Be sure to use steel for your pin, and make extras. Easy to lose in the shavings, and easy to find with a magnet. Or size your flat for a common nail, so it's easy to make a new pin.

 

[hockenbery]

Matt,

Ken described a locking pin chuck. Very useful if you cannot use the tail
stock.
for quick and dirty mount a block of wood on the lathe in a chuck or faceplate. run a cheap 1/4 drill bit into the block for instant pin. If you need the flat for the locking pin take it to the grinder and grind the flat.

I use pin chucks from wood with no locking pin. I turn a Morse taper on one end the pin on the other end.

I'll give examples of 3 different uses

1. For Christmas ornament bird houses. The Pin is 1" long and 11/32 diameter to match the hole drilled in a 1 1/4x1 1/4 x 2 blank for the birdhouse. I put the blank on the pin, bring up the tailstock rough round. I put the round blank on a matching pin set in a 2x4 clamped to the drill press drill the perch hole in the center of the grain. move the 2x4 and drill the mortise for the perch. I then put the blank back on the pin and finish turn it. The fit is tight enough to remove the tailstock for finishing the very bottom. This chuck is turned to 1" diameter where the pin begins which matches the hole drilled in the roof piece. The house is turned to this diameter so no measuring for an exact fit.
We used to do these in runs of 40-50.

2 another pin on a Morse taper is 1/4 inch diameter with a 1/8" brass rod inserted. This we use for kids classes. This is a stepped pin chuck. Lamp pull blanks drilled with a short 1/4 hole and through 1/8 hole fit this as do pen kits and key chain kits with a cone center in the tail stock. Sure beats buying a class sets of mandrels and metal step pins.

3. another wooden pin chuck we use for kid's classes is for napkin rings. With a 2 degree taper the napkin rings lock on well enough with a twist to turn to completion. The big problem with kids is they lack the hand strength to unlock the finished napkin ring. For the kids we use a 5 degree taper on the pin and lock the blanks on using a "keeper" (wood block with a hole drilled partway through). The square blank with a hole in it is put on the pin the wood block over the end of the pin and the tails stock pressure on the block holds the blank tightly on the tapered pin. The keeper is turner round to allow access to the napkin ring.

Happy turning
Al

 

[MichaelMouse]

Bidirectional type is just a milled flat, as in first picture. Hold is less, but if you have support and/or piece is light, should be enough.

Unidirectional type is a good tight hold, could be more easily adapted to a 1/4 hole, but requires a tad more forethought and machining. This is from bestwoodtools.com and is as close as you can get to a "must buy" item. Holds a treat, and makes everything associated with a bowl easier.

 

[Matt Owen]

Thank you...

Thank you all very much for your help. I've got a good idea of how I want to make mine now. Thanks again.

Matt

 

[Ron McKinley]

Using a pin chuck

Here's an article I wrote on using pin chucks to turn bottle stoppers:
http://inlandwoodturners.org/pages/BottleStoppers.pdf ........Ron