The 'modern' Longworth chuck - some comments

[rsser]

Leslie Longworth first developed this form of chuck in the 80s, here in Aus. Since then it's been a DIY project but a couple of years ago a US crowd went into commercial production. They use phenolic plates of 7mm thickness each. Buttons or grippers are slightly tapered silicon rubber, 1" high. 1/2" are now available.

Its purpose is to allow you to finish a foot on an otherwise completed bowl. Light cuts only.

The Longworth's design advantage is quick fitting of the bowl. And it does very well at that. This commercial version has a pickup at the rear to mount in a 2" set of jaws on a scroll chuck and that works well too.

An alternative is Cole jaws and they need the buttons or grippers relocated for almost every new piece and that's a fiddle, as is fitting the quadrants to a scroll chuck.

A vacuum chuck is another way of finishing a foot but that has its own limitations. And costs.

All up, this is a well made and useful bit of gear that comes with good instructions. My only dislike is the standard grippers. I find them too soft and too tall. No drama; your local rubber supplies place (Clark Rubber where I am) will provide cheap alternatives with some hacking perhaps.

I'll now be replacing them with Vicmarc style grippers as fitted to their Cole jaws. Straight swap. They're squarish with opposing faces either convex or concave. Those faces give you half a chance of using the chuck in expansion mode with bowls that have an inward curving top.

The 'modern' Longworth is available from Jim Carroll. Click (http://www.cws.au.com/shop/category/-longworth-chuck)

(I have no financial interest in any of these products, other than as a buyer).

[hughie]

I find my two Longworth chucks to be very handy. Easier to set up and use than my Donut chuck and true light cuts are the requirement with these. With mine the grippers are a mix of DIY,Teknatool and Vicmarc. The variance has occurred with the need of different jobs. My DIY have been made to date from rubber stoppers used on the end of walking sticks.

I note several comments on USA sites about losing the work piece and the results are that they shy away from using the Longworth. So it would seem its not as popular over there as else where.

IMHO the Longworth is a valuable addition to wood turning and advent of commercially made chucks is a welcome advance. I say this because not every one can produce one with accuracy. The commercially available ones would be cut on a cnc or laser set up for cost effectiveness and greater accuracy. As most laser cutters can work to 0.100mm tolerance, something that would be very hard to duplicate with hand held routers etc.

[cookie48]

I do not have one. Are they really worth having. I understand you have to be very light on the touch with them?

[Pat]

I brought one a few weeks ago and have used it once. Tailstock support is necessary until the very last moment. Easy to use with the provided buttons, I might experiment with some teknatool buttons sometime.

[nz_carver]

Hey you been shopping at Jim's pat??
I do rembember you saying at the wood show you wanted one

Hey I'm happy to give it a home

[powderpost]

I built two when they first appeared. Wouldn't be without mine now. It is true they will not stand up to aggressive cuts and can eject a project.
Jim

[TTIT]

Couldn't go without mine either :2tsup: I have lost a couple of pieces but it was my own fault - trying to cut way too heavily - easily avoided!

[rsser]

Yeah, they're just for finishing a foot.

With the same grippers I can't see that it'd be significantly poorer in grip than my VM cole jaws.

[joe greiner]

Even if you're not intending to make a funnel (:D), you can be slightly more aggressive, and insure against orbiting, by placing four strips of tape across the sides near the bottom, with both ends wrapped around to the back of the back disk. Filament tape (aka strapping tape) works best, but masking tape can also be suitable. The entire bottom is thus available for treatment.

Cheers,
Joe

[Old Croc]

Couldn't go without mine either :2tsup: I have lost a couple of pieces but it was my own fault - trying to cut way too heavily - easily avoided!

I had the same problems, :o so to minimise the risk I made an auxilary support arm with a brand new rollerblade wheel that presses against the bowl or platter to keep it hard against the chuck. Mine can be positioned anywhere and the soft wheel does not mark the finish. Since I did this I can finish my work to a very high standard. If I was any good with a camera I would post a photo. If anyone really wants one let me know,
regards,
Crocy

[rsser]

It shouldn't be this way if the grippers are adequate.

Apart from the shape diff. I mentioned above, the VM grippers also have a metal sleeve so the rubber can only compress so far, and release so far.

I've never had a piece go west on cole jaws with these.

Vermec won't say whether their Nova replacement grippers are the same as VM's. Only that they have a 6mm bore.

http://vermec.tripod.com/PDFs/teknatoolchuck.pdf

Betcha they're the same.

[WOODbTURNER]

Ern,

A few years ago I got a set of red VM stoppers from Enzo for my Nova jaws and they fit perfectly. The little Nova black ones used to leave black marks on my bowls etc.

[rsser]

Thanks WbT.

[cookie48]

Old Croc.
Your idea sounds good. Can you post a pic please.

[gidgee 1]

Hi Ern
I find that the stoppers tended to roll as the chuck is adjusted,not a problem with round ones,but I had a set of the square red ones from ?(not sure where I purchased them-it was a while ago) for the old cole jaws.When you adjust the chuck and they roll it became a PITA to adjust them so they were all facing the same way.
cheers
gidgee 1

[chuck1]

im looking into new rubber bits for mine and the local skateboard shop has lots of rubber bushings for the skaters! and different densitiy! will let you know how it works out!

[joe greiner]

Another source for large grippers is beer-making suppliers; usually white (so no staining), hollow rubber "corks."

Cheers,
Joe

[Old Croc]

Cookie48 asked for some photos of the aux wheel.
201987
I have 2 toolposts and have only shown 1 for clarity. This chuck is 22inches/560mm in dia and this platter is already finished, but put in for the photo.
201988
The main photo shows the tapered rubber grips that I got from Clark Rubber and this photo shows Vicmark poly grippers and some extensions I made up to cater for a very flared rim.
Ern said the grips should be enough, but this takes away the worry of letting 2 weeks work fly off the chuck.:doh:
regards,
Crocy

[Pat]

Here a pic of the only mod I made to my modern longsworth. The extremities are very visible even at top speed (600rpm).

It's only a little dinky one 20" or 500mm that fits inboard.

[Paul39]

Even if you're not intending to make a funnel (:D), you can be slightly more aggressive, and insure against orbiting, by placing four strips of tape across the sides near the bottom, with both ends wrapped around to the back of the back disk. Filament tape (aka strapping tape) works best, but masking tape can also be suitable. The entire bottom is thus available for treatment.

Cheers,
Joe

Here is my version on a jam chuck.

Thanks for the idea, Joe.

[wheelinround]

Here a pic of the only mod I made to my modern longsworth. The extremities are very visible even at top speed (600rpm).

It's only a little dinky one 20" or 500mm that fits inboard.

Pink curtains on the windows next Pat:q

Having seen Pats in person its a damn good idea (not the curtains tho)

[Pat]

Pink curtains on the windows next Pat:q

No I have sun reflecting material on both windows, very dusty black colour.

PS, Mal's already been!

[wheelinround]

No I have sun reflecting material on both windows, very dusty black colour.

PS, Mal's already been!

:o Personal delivery damn I won't get to see it so photos lad photos. :doh: No use going to Kiama now Pat got best pickings.:C

[Old Croc]

[QUOTE=]Here a pic of the only mod I made to my modern longsworth. The extremities are very visible even at top speed (600rpm).

Pat, could you describe how you did the colour,
Crocy

[Pat]

Orange Artline No 40 Paint Crayon applied at speed. It's not100 percent when resting but as you can see very visible at operating speed.