Holding a square in 4 jaw chuck

[Raif Harik]

Hi, I want to get a collet chuck for my lathe. There are a couple out there but they are pretty pricey and most of them are for 1 x 8 tpi and I'm 1 1/4 x 8 tpi. I've seen on amazon the have these little collet mounts for CNCs. It's basically a square block with the collet holder attached. They have a through hole which is nice, and they are cheap. I was thinking I could just put one of these in my vicmarc 120. They come in square and hex. I would be using it for pen turning so it wouldn't be tremendous torque or anything.
My question, as usual, is: am I crazy? and if not would it be better to got with a square or a hex.
Here are some pics. I also just saw one that has a straight round shank.
thanks

 

[John Torchick]

How big is the square you are turning? I can fit a 2x2 block in my SuperNova2 chuck jaws.

 

[Raif Harik]

For a pen it's ~ 3/4 x 3/4 or 3/4 x 5/8. So it does not fit in the standard jaws.

 

[Don Wattenhofer]

The primary reason for a collet chuck is accuracy and it is nice to be able to run the round work piece into the head stock spindle such that you can work on one end although that is limited to about 1/2" thru a #2 Morse taper. The square block style would probably not be accurate held in a woodturning jaws. The price listed probably does not include any collets so that would be an additional cost per collet.
The lowest cost is the morse taper mounted style if you can find one as a kit with a set of collets, which is what I purchased for $45.00 before the Beal collet chuck came on the market. The square and Hexagonal mounts are meant to be used clamped in a vice on a milling machine to mill a square or hex on a shaft simply by rotating to the 4 or 6 possible positions.

 

[Michael Lamka]

Not meant to be off-topic, but a collet chuck might not be the best choice, or even a good one, from the work standpoint. My chuck is a Penn State job with multiple jaws. The smallest set of jaws grips pen blanks nicely. Even grabs not-square pieces - grip the wood in the jaws, run the tail stock with a live center mounted, into a pre-marked center and then tighten the jaws. All ready to turn.

PSI also sells a two jaw chuck (or just the jaws) just for pen blanks. It doesn't grip as securely as a 4 jaw chuck because it is designed, primarily, for drilling, so turning with it might be problematic.

If turning blanks for kits, maybe just drilling and mounting on a spindles would be better than any chuck?

 

[John Torchick]

IMO, collet wouldn't be the best for turning as Michael stated.. My SN2 has pen jaws for drilling. Mandrel for turning with appropriate bushings. Raif, you might look further before you buy.

 

[hockenbery]

For a pen it's ~ 3/4 x 3/4 or 3/4 x 5/8. So it does not fit in the standard jaws.

i have #1 jaws for both the talon and stronghold. They close to 1/2” great for holding small square stock.
also great for holding Finials with 1/2“ or 3/4”tennons.

the vicmarc has 25mm and 35mm pin jaws that look similar to the ONEWAY #1 jaws.
you could call woodworkers emporium and find out if they would work for you. I have a Vic 120 but no pin jaws.
this is what they show in the Chuck manual.
in a pinch you can Chuck small pieces inside the through hole holding with the noses of the jaw slides.

 

[Raif Harik]

Hi, so here are my concerns and criteria. I need something to hold a longer blank. 4 1/2" for drilling. That has been turned mostly round. My VM120 won't hold it with regular jaws and I'm not going to switch jaws. Too lazy. The folks on the pen turner forum all seem to like the collet chucks. Yes psi has one but it's 1 x 8 tpi. This would be pretty cheap ~$30 and I could just stick it in my VM. The alternative would be to get pen jaws for my chuck, or a dedicated pen chuck from psi but that's 120 after thread adapter. I already have a few collets. Seems I could turn round to 5/8" and stick it in the collet at it would hold it straight while I drill. Don't really know what other options I have.

 

[Brian Gustin]

Hi, so here are my concerns and criteria. I need something to hold a longer blank. 4 1/2" for drilling. That has been turned mostly round. My VM120 won't hold it with regular jaws and I'm not going to switch jaws. Too lazy. The folks on the pen turner forum all seem to like the collet chucks. Yes psi has one but it's 1 x 8 tpi. This would be pretty cheap ~$30 and I could just stick it in my VM. The alternative would be to get pen jaws for my chuck, or a dedicated pen chuck from psi but that's 120 after thread adapter. I already have a few collets. Seems I could turn round to 5/8" and stick it in the collet at it would hold it straight while I drill. Don't really know what other options I have.

Well, I would think, you can chuck up a waste block in your jaws, and then turn a recess in one end for a nice tight fit to your round blank (even a 1/8 inch depth) and glue it in , sacrificing a 1/8 inch of your blank, then when done, you can just turn away the waste block? I do that frequently when turning (or trying to turn) finials and other small stock.. Also, with a little patience, if you have non-round stock to turn you can do the same thing but you have to cut your recess with a nice sharp chisel..

 

[Raif Harik]

Hmmm this sounds cheap and fairly lazy. Two criteria pretty high on my list. I've already killed a number of nice blanks by the drill going through the side. I need something better.
Luckily the nice thing about pens is/are you can get a million blanks outta something I wouldn't normally think to put on my lathe.
I'll give this a try. I'll just drill a 1/2 in hole in the waste block on the lathe then glue in the trued, sized blank. I just hope this helps get a straight drill on the thing.
Thanks

 

[Tom Gall]

Hmmm this sounds cheap and fairly lazy. Two criteria pretty high on my list. I've already killed a number of nice blanks by the drill going through the side. I need something better.
Luckily the nice thing about pens is/are you can get a million blanks outta something I wouldn't normally think to put on my lathe.
I'll give this a try. I'll just drill a 1/2 in hole in the waste block on the lathe then glue in the trued, sized blank. I just hope this helps get a straight drill on the thing.
Thanks

How about this - two options. 1) Drill a through hole (1/2" or 5/8") in a square block of wood that will fit your chuck jaws. Cut a kerf on one side to meet the drilled hole. Insert dowel (workpiece) and mount corner edges of your block between the jaws. Insert center dimple on revolving center in tailstock and tighten your chuck jaws to pinch your dowel securely....drill hole.
2) (preferred?) Drill a through hole (1/2" or 5/8") and cut a kerf as above. Mount between centers (in the through hole) and turn round. Turn a tenon to match your jaws then mount as above. Mark the tenon to match one of your jaws for future concentricity. If you make this carefully it should be more precise than option 1.

 

[Raif Harik]

Dang!!! Nice one Tom!
Thanks!

 

[Raif Harik]

Well that worked nicely!
Two follow up questions. Maybe better as separate posts.
1) it seems to really help the clamping mechanism when the blank is not turned two small. I wonder if there is some sort of pattern tool for turning to a specific diameter.
2) and more concerning is that there seems to be serious run out on the drill bit. Or ... Whatever. Ive been trying to pre drill with an 1/8th bit. But it seems to not be pointing directly at the hole left by the live center. Maybe like 3/64ths to the side. Once I start going it seems to be wobbling pretty bad. So I switched that out for my full size bit. Still was a bit off. I can't tell how much run out there is but I can say the whole is about 1/8 in off over 5 inches.
So it could be my beat old jacobs chuck. Came off an old craftsman drill press from some 25 years ago. The lathe is but a few months old. I "feel" like it's been running true.
Any thoughts would be appreciated.
Thanks

 

[Clifton C]

Sounds like your headstock and tailstock might not be axially aligned. Have you checked by installing a good drive center and live center and bringing them point to point to see if they align?
If off, you can adjust with the feet. For example, while looking from the tailstock towards the headstock, If the live center point is to the right of the drive center point raise the right tailstock leg to shift the tailstock to the left, bringing the points into alignment.

 

[Brian Gustin]

In addition to Clifton's comment - also want to check your tail stock - does it have much movement when it is not locked down? If so, when you lock it down, you may not consistently get it precisely centered (My HF lathe has a LOT of slop to it so I often just leave it loose and let the drill and work piece work themselves to center very gently, and once the drill starts in a bit, then I will shut off the lathe and lock down the tail stock.. helps a lot.. )

 

[Don Wattenhofer]

The drill chuck can be checked for run out simply by rotating it 180 degrees to see if the miss alignment switches sides.

 

[Raif Harik]

So I went out looked and found that with the head and tail stock points together the tailstock pointed below the headstock by at 1/8 in.
Not sure how to fix that. Is it a matter of shimming the legs or something on the lathe it's self?
Thanks

 

[Brian Gustin]

What lathe? brand and model? I had that same problem (very bad) with my HF lathe, which had a rotating headstock.. at first I shimmed it up (0.120" thick shim needed) under the headstock (which could rotate to the side for outboard turning) .. later on I tore the lathe completely down and completely went over it - cleaning , lubricating, and filing/grinding off uneven surfaces, etc. upon reassembly it all fit up much better and did not need shims.. Some lathes with fixed headstock, you might have to file off one end of the tailstock where it rides on the ways (or, check for build-up and clean the lathe ways and tailstock) .. Others, might be able to shim up headstock.. Really depends on what lathe you have.. also - be sure and rotate both the drive center and live center to 90 degree intervals to a full 360 degree rotation (one at a time) and re-check each time you move one of them to see if possibly your drive center point or live center may be bent or off (in which case the offset will change)

 

[Raif Harik]

So this is a Laguna 24/36. I had done a little dance to the tune of about 6" to the left a week or two ago. But I feel like maybe this misalignment has been going on for a while. I think I will post this as a new thread as it's pretty off topic by now.
thanks