PDA

View Full Version : Finial Chuck Jaws



Texian
24th Sep 2009, 10:17 AM
Inspired by the "Finials" thread, I decided some much needed finial practice was in order here. Not wishing to use a 50 mm square blank (about the smallest my jaws will hold) to make a 16 mm diameter finial, some accessory jaws were needed. The first atempt (wood inserts) gripped securely but did not center and took 3 extra hands to get everything in place. The second attempt, crudely made from some rusty steel angle, centered remarkably well and gripped the wood securely, but a slight hitch in my gittalong (catch) actually bent two of the jaws. After straightening and cutting 5/8" (16 mm) off the "jaws" to reduce the leverage of the next catch, they work pretty well. Could be made more easily and accurately from 5/8" square bar stock with screw holes countersunk to correct depth. Now my finials need more practice.

issatree
24th Sep 2009, 11:15 AM
Morning Texian,
Why didn't I think of making some Jaws like that. I have 3 of the older style 2 tommy bar black Nova Chucks, which I think are almost the best & quickest in the business.
I needed some longer Jaws, & paid $91.80 for some Pinocchio Jaws. I'm very satisfied with then, but the cost at that time was a bit awkward.
I will most certainly have a go at your design, but will try to strengthen the sides to stop the bending, splaying.
Of course that happened with the small Jaws with only 1 screw per Jaw.
Very ingenious, & so so simple.
Regards,
issatree.
<input id="gwProxy" type="hidden"><!--Session data--><input onclick="jsCall();" id="jsProxy" type="hidden">

hughie
24th Sep 2009, 11:37 AM
Its so darn obvious when you see it done, nice one Tex :2tsup:

It opens the door of possibility for all sorts of tailored jaw mods

Ozkaban
24th Sep 2009, 11:45 AM
Clever idea. I'm impressed you managed to get them to centre so well.

Would the wooden inserts work better with some double sided tape, just to hold them in place while you tightened the chuck?

Cheers,
Dave

Skew ChiDAMN!!
24th Sep 2009, 11:57 AM
Clever idea. I'm impressed you managed to get them to centre so well.

Ditto! And for something of that small a diameter, centering is important.


Would the wooden inserts work better with some double sided tape, just to hold them in place while you tightened the chuck?

A rubber band works well. :)

I turn similar "adapters" as one piece, with a rebate around the outside for a rubber band to to sit in so it's not chewed up when I tighten the jaws, and then quarter 'em on the bandsaw.

Texian
24th Sep 2009, 12:00 PM
Thanks for your comments Issatree and Hughie. The jaws are about 5/8" wide and 5/8" deep, so could easily be made from 5/8" (16 mm?) square bar stock. Just countersink the screw holes so the screws can reach the correct depth. Both my chucks are the $99 Grizzly, which are said to be copies of a Vicmarc. The screw hole spacing seems to be about .709" (a strange number), which is a lot like 18 mm (not so strange number).

I admire and appreciate the spirit of folks on this forum who like to make stuff. Seems like most people (not all) on the U.S. forums just want ot buy stuff. Thanks again.

Ed Reiss
24th Sep 2009, 12:05 PM
...damn nice adaptation, Tex :2tsup:

Frank&Earnest
24th Sep 2009, 12:06 PM
Yes, impressive. The precision requires proper metalworking machinery, though, I wonder how many woodworkers would have access to that. I have found that a relatively cheap chuck with 4 sets of jaws costing less than A$300 can do almost anything, from the small finial to the 14" bowl to off cente turning.

This said, the challenges of toolmaking are probably what saves turning from triviality. Well done! :2tsup:

Ozkaban
24th Sep 2009, 12:07 PM
I turn similar "adapters" as one piece, with a rebate around the outside for a rubber band to to sit in so it's not chewed up when I tighten the jaws, and then quarter 'em on the bandsaw.

Neat idea :2tsup: thanks.

Texian
24th Sep 2009, 12:18 PM
Thanks Dave and Skew. The double-side tape should work fine with wood inserts for limited use. I wanted something that could be removed and reinstalled in repeatable fashion like regular chuck jaws.

I clamped a "fence" to the drill press table, put "automatic" center punch in drill chuck and punched first hole location in all four pieces. This is why they center pretty well. Then scribed the .709" spacing on one piece and moved fence to center punch those four holes. Not perfect but pretty close.

Thanks Ed and O.
F.&E., They would certainly be better with proper metal working tools (like a nice milling machine), but I do not have them.

Skew ChiDAMN!!
24th Sep 2009, 12:30 PM
:think: I imagine that if you made the jaws from brass stock, then you could fit them to the chuck and true them up with a scraper?

(Just pondering on ways that I might be able have some success. :;)

Ozkaban
24th Sep 2009, 12:31 PM
I clamped a "fence" to the drill press table, put "automatic" center punch in drill chuck and punched first hole location in all four pieces. This is why they center pretty well. Then scribed the .709" spacing on one piece and moved fence to center punch those four holes. Not perfect but pretty close.


Sounds like a good way of doing it. I guess if the spacing is slightly off it wouldn't matter so much (so long as the screws were tightened up in the same order), but if it's all referenced off a fence it should be at least even. Makes sense to me!

Cheers,
Dave

BobL
24th Sep 2009, 12:35 PM
:think: I imagine that if you made the jaws from brass stock, then you could fit them to the chuck and true them up with a scraper?

(Just pondering on ways that I might be able have some success. :;)

That's more or less what I did. I made the chuck jaws, attached them to the chuck and then put the whole chuck in the Metal work lathe and turned them true.
http://www.woodworkforums.com/attachment.php?attachmentid=68294&stc=1&d=1204289320
http://www.woodworkforums.com/attachment.php?attachmentid=72012&stc=1&d=1209194788

FUll threads here (http://www.woodworkforums.com/showthread.php?t=71420) and here (http://www.woodworkforums.com/showthread.php?t=67474)

BTW I like your jaws Texian. Somewhere I have a half finished set that are similar to yours but are actually made from solid blocks of ally so the will not splay as much at the tips. I often hold small stuff by the last 1/2" of so of the tips and find they splay too much and good out of parallel to teh turning axis.

Texian
24th Sep 2009, 12:57 PM
Skew, The truing up (brass jaws) could work, but they would have to be at least partially clamped on something to take up the slack in the scroll mechanism of the chuck.

Thanks Bobl, That's why I suggest using solid 5/8" (16mm) square bar stock instead of the thin, rusty steel angle that I had. There will be no tips to splay out.

Thanks Ed.

artme
25th Sep 2009, 01:06 AM
Good one Texian!:2tsup::2tsup::2tsup:

My vote for Tip of the Month.

hughie
25th Sep 2009, 01:26 AM
The truing up (brass jaws) could work, but they would have to be at least partially clamped on something to take up the slack in the scroll mechanism of the chuck.



A simple method that is used in many engineering shops. Is to open the jaws on to an old bearing ring ie the outer part of a ball bearing. Then machine the inside of the jaws, as the bearing ring is ground and hardened it makes an ideal mandrel to hold the jaws true for machining.

What I like about idea is that its simple and effective and thats hard to beat.

Texian
25th Sep 2009, 03:13 AM
Thanks Artme and Hughie. I appreciate your replies.

Would really like to build Ad's oval turning device, but I visualize it with roller bearings, ball bushings, hardened and ground "slider" shafts, etc. But that would take some $$ and a machine shop. Sadly I have neither. It's a great design, elegant in its simplicity.

hughie
25th Sep 2009, 01:12 PM
Hi Tex,

have a look at this link, they are over your way and by far the cheapest I have found on line, might be do-able over time with this mob

http://www.vxb.com/ballbearings.html?gclid=CIa-vabXi50CFQkwpAodTWwj1g

Texian
25th Sep 2009, 02:10 PM
Hi Hughie,
Thanks for the link (added to my favorites list). They have a lot of good stuff. I can do metric. Same as inches only different. Looks like the device could be built for less than $250 US for parts. Maybe another hundred to have some steel plasma cut and a little machine work. A great little machine design project like I used to love about 20+ years ago. Doubt if I could get funding approval from the Chief, but will keep thinking about it.

Ad de Crom
25th Sep 2009, 03:14 PM
Richard, a simple and effective solution for turning finials.
Looks great.
Ad :2tsup:

tea lady
25th Sep 2009, 05:16 PM
:2tsup: Brilliant! :cool:

Texian
26th Sep 2009, 01:45 AM
Thanks Ad and T.L. Appreciate your response.

NeilS
28th Sep 2009, 11:38 PM
Clever idea. I'm impressed you managed to get them to centre so well.



:2tsup:...on the idea Texian.

But, is it so critical about the jaws being exactly on centre if the piece doesn't have to be remounted? Worst that can happen is that you lose a tad off the possible width of your blank.

...

Texian
29th Sep 2009, 12:27 AM
But, is it so critical about the jaws being exactly on centre if the piece doesn't have to be remounted? Worst that can happen is that you lose a tad off the possible width of your blank.

Not critical at all Neil. At least not for me. I did not mean to suggest that mine center perfectly, just close enough that the wood looks well centered by eyeball. I use the tailstock and a center mark to align that end of the blank before tightening the jaws. I did make a half dozen practice finials. One was not too bad and the rest were mediocre. More practice needed.

artme
1st Oct 2009, 10:38 AM
Just had a squirt around the internet and came across the Beale Chuck Puck.

Solves the problem if holding 3/4" and 1" square stock very nicely. Have a squizz for yourself.

Texian
1st Oct 2009, 11:07 AM
That's a dandy little doodad, and only US$12, plus shipping of course. But what if all your stock is 7/8". I know, rip it down to 3/4". Thanks Artme. A very handy item for those who can't or would just rather not make their own.