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Mounting collet chuck on new old lathe
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Author:  kkrace [ Mon Mar 30, 2015 12:37 am ]
Post subject:  Mounting collet chuck on new old lathe

I picked up a new old lathe a few years ago and have just had it in mothballs. A buddy asked me if I'd make some suspension links for him so I decided that was a good enough excuse to set this one up. My other lathe has change gears and its a pain in the ass to change feed rates.
He bought hex stock and I'll be turning most of it down round just leaving the hex on the ends so you can hold the links with a wrench.
I suggested buying round stock and just letting me mill a couple flats on them for an open end wrench but he wasn't having any of that. I would have just used my old old lathe to drill and tap the ends to accept the spherical rod end bearings.

I bought a collet chuck for it since it didn't come with the adapter for collets and found someone at Cabin Fever Expo that send me some old used backing plates that would fit the Sheldon spindle. The other reason to use the collet chuck was I could use 5c collets instead of the smaller ones the small diameter spindle on the Sheldon would limit me to.

When I put the backing plate on the lathe and tried to true it up I noticed every time I loosened it up and ran it back on the spindle I did not run true. The part that isn't threaded on the that goes on the spindle was oversized even though the threads were correct. I bored that part of the backing plate out and found a piece of steel pipe I could make a press fit bushing out of.

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Author:  kkrace [ Mon Mar 30, 2015 12:41 am ]
Post subject:  Re: Mounting collet chuck on new old lathe

I screwed the backing plate on the the spindle backwards to bore out the existing hole to fit the steel sleeve. With the new sleeve pressed in the backing plate the plate now indexes really nice and I have a nice tight slip fit over the shoulder on the spindle.

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Author:  kkrace [ Mon Mar 30, 2015 12:45 am ]
Post subject:  Re: Mounting collet chuck on new old lathe

Now I have to machine the backing plate to hold the collet chuck. There is a recess in the center of the chuck that centers it. It's crucial to cut the backing plate so it fits without play into the back of the chuck. If you don't get this right the chuck will never spin true and I'll loose all the advantages over a 3 jaw chuck

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Author:  kkrace [ Mon Mar 30, 2015 12:53 am ]
Post subject:  Re: Mounting collet chuck on new old lathe

Now that that issue is solved time to machine the backing plate to accept the chuck. The backing plate was used and had been machined to hold a larger chuck which is good since its easier to remove material than add it back on...unless your Mark!

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Author:  kkrace [ Mon Mar 30, 2015 1:03 am ]
Post subject:  Re: Mounting collet chuck on new old lathe

Before and after

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Author:  kkrace [ Mon Mar 30, 2015 1:07 am ]
Post subject:  Re: Mounting collet chuck on new old lathe

Collet chuck has a nice tight snug fit onto the backing plate. Now to take the backing plate to the mill to drill and tap the bolt circle that holds the chuck to the backing plate. There are existing holes already drilled for whatever chuck was orginally mounted on it. The extra holes don't help me any since they are the wrong diameter bolt circle to be of any help.

The raised section centers the chuck. The three bolt circle just holds the chuck to the backing plate.

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Author:  kkrace [ Mon Mar 30, 2015 1:12 am ]
Post subject:  Re: Mounting collet chuck on new old lathe

Trying to decide if I should drill and tap the holes or just drill through holes and put nuts on the back?

I have a DRO on the mill so doing the bolt circle is a piece of cake once I figure out the dia of the bolt circle on the holes in the chuck and find the center on the backing plate. The DRO has a function built into it to find centers and calculate bolt patterns. Once you have located the center of your part you put in the bolt pattern dia, the number of holes and how many degrees off of 90 to start the first hole in the pattern.

I probably should have drilled the mounting bolt pattern before turning the backing plate in the lathe. Now I have to be careful not to warp it or ding the surface the chuck mates up with it up when I clamp it in the mill. Doh!

Author:  kkrace [ Wed Apr 08, 2015 10:09 am ]
Post subject:  Re: Mounting collet chuck on new old lathe

Finally got some time to put the backing plate on the mill and drill and tap the bolt pattern. Came out perfect and spins incredibly true. So nice not having to rely on a jaw chuck. I'm going to look for a square collet at the Cabin Fever Expo this weekend. If I can find one with a half inch or bigger square opening its nice to have. If I get one with a half in square I'll pick up some 1/2x1/4 brass bar stock. You put two pieces in the chuck sandwiched together and you can drill the center out to any size you need and have a clamshell for chucking any size I want.

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Author:  kkrace [ Wed Apr 08, 2015 10:12 am ]
Post subject:  Re: Mounting collet chuck on new old lathe

.

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Author:  mk e [ Mon Apr 13, 2015 2:30 pm ]
Post subject:  Re: Mounting collet chuck on new old lathe

Nice job! You're going to LOVE having a collect chuck and wonder how you lived without it :)

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