2" reverse collet?

[Luke Pighetti]

Hey guys,

99% of the wood I turn is a cylinder that already has a 1.850" inner diameter. I have a sacrificial ring that holds the outside tightly so that the wood doesn't split when on the lathe.

I typically use a mandrel that I cut out of scrap wood. It works fairly well, but up until recently the wood I've been turning was pretty easy to turn.

I'm just starting to get into burls and some other less forgiving woods, so I feel as if I need a decent chuck.

Now, I literally only need a tool that will hold a 1.850" ID, but it needs to be able to handle +/- about 0.050", which is why the mandrel doesn't always work.

The depth for grabbing onto the workpiece at this diameter is about 0.300".

Is there some kind of collet I can use? Or perhaps a 3 jaw self centering chuck?

The other thing, is I need it to hold it's size fairly well without anything in it. That way I can easily slip on workpieces for sanding, and slip them off, without having to grab tooling each and every time.

Also, the workpieces are very short, so no tailstock support is used.

[Roger Chandler]

Luke.....pictures would help with diagnosing your issues............I would much prefer a 4 jaw chuck over a 3 jaw any day, and a scroll chuck at that, not one where you have to adjust every jaw individually. I use supernova2 chucks and I have one set of jaws that will go down to the 1.850, actually, 1.5" diameter and will expand outward to 2.75" or so..........they are spigot jaws and have serrated surface on the inside when in contraction mode and dovetail configuration in expansion mode..........

If you can post a few pics of your set up and the cylinders you are trying to turn..........I would think there is a wealth of knowledge on this forum and you will get some very good responses!

[Luke Pighetti]

Roger, they say a photo is worth a thousand words. I'd say in this case maybe ten thousand. Here's a quick picture of what's going on here. The item that is chucked up is actually totally finished. The slot is cut before turning.

239215

[Dennis Ford]

I think your rig is plenty adequate and probably better than a chuck for this specialized turning.

[Marvin Hasenak]

What you basically described in your first post is an expanding arbor. The 1.85 is an odd size so you would have to get one then have it machined to size. McMaster Carr or Enco should have the expanding arbors on 2" sizes. You will probably have to have both ends machined, one to the 1.85 and the other to fit a chuck to fit your lathe.

[Luke Pighetti]

The only reason I'd want a chuck is for the slight bit of adjustability and so I could really crank on it so it wouldn't eject, which is does at times now unless I pack a corner with tape first.. That's really why I was asking for a reverse collet. Reverse collets in small denominations would be perfect.

[Roger Chandler]

Luke......the rig you have in the picture is pretty slick. I think you could make a collet out of wood which would fit into standard jaws on a chuck and have the diameter of the inside of the wood collet to match the size you need [1.850?] That would just take a little turning on your part, but looks to be a feasible and inexpensive solution.

the scroll jaws on the chuck would clamp down on the wooden collet and give a secure hold, and would work better than your faceplate, in my opinion. What is the piece you have turned in the picture above? [what is it used for?]

[Luke Pighetti]

Did you have something in mind for an expanding wooden collet? I've been trying to figure out how I could do that. Use my bandsaw to cut the face into pie sections and then use some kind of tapered screw to expand.

Here's a photo of what they are used for. It's a rewarding item to make.

http://vibrolabs.com/wp-content/uploads/2012/08/blog-1.jpg

[Alan Zenreich]

Looks like a nice project (as I eye my own Grado headphones)
Do you offer these as an aftermarket upgrade to existing headphones, or make components for headphone companies?

[Luke Pighetti]

I make them for audiophiles who want to dig into their own cans for a little upgrade. :) I have a website, but I don't know if it's okay to post them on this forum.

I just finished cutting my first pair of "Limiteds." I have two products, both Honduran Mahogany. This pair is curly maple gifted from a friend and boy is it beautiful. I've never finished maple before so I'm kind of at a loss as to what happens next. :) It has a few small voids that I want to fill and I really want to bring out the curl. Right now it only has a very thin coat of linseed oil on it. Beautiful stuff.

[Alan Zenreich]

Luke, I found your Etsy site... thanks

[Marvin Hasenak]

I would buy one of these, take it to a machine shop and have the end milled down to 1.850. The left end might also need to be milled, that will depend on your lathe and the type of chucks you have. I would use a collet chuck from either Beall or PSI. Then have the shank milled to 3/4", that is if it is 1" that it appears to be. With the arbor and the collet chuck the "ear" piece can be removed and replaced without getting out of round. I would not even attempt to use the arbor on a 4 jaw chuck unless it has jaws like on a metal lathe chuck.

http://www.use-enco.com/ProductImages/0960498-21.jpg

This arbor is Enco part # 319-2820 Price is $58.78

I have used these expanding arbors for the last few years, as long as you don't abuse them, they will last almost forever. Too bad you cannot use a standard size, like the 2" or the 1.75" then you could save a few dollars at the machine shop. You might try looking for a metric size, or look at bigger machine shop supply houses, they might have different sizes, I never needed that so I have never looked.