Interest in making a Longworth aligning chuck?

[reible]

In some recent posts I've been made aware of the use of a longworth like chuck for doing alignment of segmented assemblies. Those chucks have long interested me but I never sat down to study how they are made or the geometries involved. That has changed over the last couple of days.

I have thought about what I would like to do as far as making one and I'm to the point of having to figure out what hardware I need and get it ordered. I'd like the hardware in hand before I finish the design as I've been bitten before going from descriptions.

I'd like to judge the interest here in making one and while mine will be for alignment the basic design would allow for making one that fits your lathe and allows turning....... Keep in mind these are for turning at lower rpm so a stock shopsmith might be too fast.

If you don't know what they are and how to use them do a google search.

This will be a router project and I might well want to use my OPR for it but the use of a router and trammel would also work.

Not sure when I'd get to it but perhaps before the snow flies here in Aurora.

Ed

[BuckeyeDennis]

Sign me up .. sounds like fun!

[ChrisNeilan]

I'll post pics tonight of my setup...

[redleg]

I made one maybe a couple years ago. I was lost and confused doing the first one but finally got it right on the second try.

Front side

IMG_20161003_170625 (768x1024).jpg (497.49 KiB) Viewed 12390 times

Back side

IMG_20161003_170711 (768x1024).jpg (459.11 KiB) Viewed 12390 times

I believe the following link is what I used:

http://woodcentral.com/cgi-bin/readarti ... ir=turning

After Googling it today this may be a better article.

http://ravenview.com/blog/2010/10/17/ho ... rth-chuck/

[ChrisNeilan]

No pics yet, but this gives you the general idea. It's from Capn' Eddies web site.:
http://www.eddiecastelin.com/yahoo_site ... 194426.pdf

[reible]

I stopped at a Rocklers today and got the Ron Brown's Best Gripper Buttons with hardware. That was $24.99 minus a 20% off coupon I had so figure $20. From what it looks like they will work for about 1" material thickness.

I will be basing mine on this hardware but it by no means the only hardware out there and of course there is home made.

Since mine is not going to be spinning anything I also got two cutting boards from the Sams Club. These boards are ruffly 15" x 20" x 1/2" thick. Cost was $8.98 each. The pair will give me the 1" thickness the hardware kit seems to have.

I think I will make the circles 14" in diameter, but I have not decided for sure.....

Ed

[ChrisNeilan]

Here's pictures of my set-up of Lloyd Johnson's Stomper and Longworth Chuck. The chuck simply used four bolts with no nuts, bolts or rubber bumbers, just the bolts. Works great! Remember, this is table mounted, not to be used on the lathe, so no safety issues!

[reible]

I got a good start on the project today. I made a template then cut one of the two disks out and put the slots in. It seems to be working but I will not know for sure until I get the second disk done and put them together.

Here it the first disk:

IMG_2912sc.jpg (73.4 KiB) Viewed 12160 times

If it works I have drawings and pictures that I will add. If not then it is back to the drawing board.......

If all goes well I'll take care of some medical testing stuff in the mid morning and be ready to start cutting again after lunch. Actually I'm up to the point of cutting the slots on the second disk so maybe a hour or so away from testing once I get back on it.

Ed

[reible]

My time estimate was pretty good. Of course a good portion of that was clean up after the plastic chips go everywhere. I'm sure I'll be finding them for a while as I only got the ones that were easy to see.

Well first the good news. Works as slick as slick can be!

I've posted a lot of construction details here:

http://www.shopsmith.com/ss_forum/gener ... 19052.html

I've decide there are plenty of online sites with details as to how to do the layout and I don't need to add those details here. If you look online and can not understand what is going on I will attempt to help you figure it out but with the low number of readers on this thread I think the interest is to low for me to take a lot of time on the subject.

I will give a few details here. The circle sizes I picked were 3", 5-1/2" 8", 14" and an over all diameter of 15".

Now after building this I have a hunch that it might actually work on the lathe. It wasn't what this build was about but now that I have a template I might go with a combo plywood and cutting board design for turning. I think the plywood would be better for attachment to the lathe. The other option would be the addition of a wood block to the plastic for better support.......... any way that is a project for later. It would also be interesting when it becomes dynamic rather then static.

The material was as I mentioned cutting boards from the Sam's Club.

IMG_2896sc.jpg (114.35 KiB) Viewed 12119 times

This is how the parts go together:

IMG_2915sc.jpg (96.71 KiB) Viewed 12119 times

A 12" bowl or the likes would fit and if it were a thin tapper rim perhaps a bit more.

IMG_2914sc.jpg (102.87 KiB) Viewed 12119 times

With all 8 gripper in place the smallest it will go is shown here:

IMG_2916sc.jpg (91.2 KiB) Viewed 12119 times

This is somewhere around 7-1/4".

IMG_2913sc.jpg (107.09 KiB) Viewed 12119 times

Of course the larger objects need more support but a smaller object can get by with only 4 grippers. In that case the smaller object mode looks like this:

IMG_2917sc.jpg (85.93 KiB) Viewed 12119 times

That gets the size down to about 4-3/4". Sorry I have a picture but it is messed up and would confuse more then it would help.

Now for alignment of parts I might make a few adjustments to what I have. The grippers can be replaced with straight parts etc. Not at the point of using it so again I will defer to a later date.

It was a fun adventure making one even if I never use it.

Ed

[BuckeyeDennis]

Very nice, Ed! Is there a segmented bowl forthcoming?