Jar fitting jar snug into another jar for woodturning

[Mike N]

I want to carve 2 jars from 2 different color woods. I need one to fit snug into the other so I can glue them and turn it. Has anyone done this or have a simply way of being accurate. I tried but my accuracy is not good.

thanks
Mike N

[cajunpen]

I want to carve 2 jars from 2 different color woods. I need one to fit snug into the other so I can glue them and turn it. Has anyone done this or have a simply way of being accurate. I tried but my accuracy is not good.

thanks
Mike N

Mike, I'm not sure I understand what you are trying to do - but if you are trying to actually carve two jars that can fit one into the other, I don't think that you are going to be able to do it on a CW machine. You are limited to a depth of cut of 1". Hopefully I answered your question.

[Mike N]

Yes I want to fit one jar in the other. And yes 1inch is fine. I am acually trying to make jewerly boxes. If I can this working I will make the base of the jar the make the cover the same way. My problem is to really get a tight fit. I wanted to know if anyone has ever done this before.

[Mike N]

http://www.makerofboxes.com/

Bill, check this web site to see what my final goal is.

Mike N

[Greybeard]

Hi Mike.
First thanks for that link - those boxes are some of the most beautiful pieces I've seen, and strongly recommend anyone reading this thread to follow the link. Just for sheer pleasure.

Back to your problem. His boxes are turned first to fit each other, then after gluing, carved internally with a rose engine.
Are you trying to reverse the process, and use the cw to carve the inside first ?
If you can turn, why not stick to his method ? Or are you trying to produce rectangular versions ?

Could you do a simplified line drawing of what you are aiming for regards the boxes(leave out the carving) in terms of sizes and shapes ?

Regards
John

[Mike N]

John, exactly, I am trying to eliminate the turning part to make the 2 jars fit into each other. Once I use the CW to fit the jars into each other I will then turn them so that some of the colors of the wood on the inside jar get exposed like on that web site. Turning 2 jars to fit exactly is a horror story I thought CW could do it better if I find out how to do it. I tried but keep going back and forth because they don't fit exactly.

Mike N

[Greybeard]

So if I've got the picture right, what you need to do is to cut a circular pocket in one piece of wood the exact size of a disk you've got the cw to cut out of another piece ?
This is the same problem that has been raised with the guitar makers trying to get inlay work cut accurately.
You have a simplification that you are trying to cut a circle(correct?), but the complication of a much deeper cut with the wall profile well controlled.

A lot of threads mention the problem that the carving bit is tapered, and everyone seems stuck on the idea that it's necessary for the wall of an inlay to be vertical.
It isn't. If you can imagine the side of the internal cut is sloping outward, and the external cut is sloping inward, all you need do is turn the internal piece over, and it will drop down and give you a tight fit.
If you've done the sums right the top surfaces will be level. If not, it will be too high, or too low, but it will still be a tight fit.

Is this getting you forward ?

John

[Greybeard]

Mike, I've just had another thought, given the size of what you are trying to do, because I'm in the process of restoring my old modelmaker's lathe, with a 2" swing and a 10" bed.
Could you turn your wood jar "blanks" on a small metal working lathe ?
This would give you the control and accuracy you need to get the two to fit.
You don't need a metal lathe, just lash up a cross feed device to fit your own lathe ;)
John

[Mike N]

John, yes basically what I want to do is fit one circle into another. Or a round block into a cup. I want the CW to carve a cup with straight walls and straight bottom then on another piece of wood I will carve a tube the will fit into the first cup. Yes it is like inlay. BUT I need an exact fit. Once I'm done on the CW I will turn it and use a Rose Engine.(don't have on yet but it is on my list of toys) I just want to see how accurate I can get these things fitting into each other.

Mike

[Mike N]

John, I have never seen or used a metal lathe but that sounds like it would help if you say it will give accuracy. But you also talk of a cross feed on my existing lathe do you have any suggestions who makes them or do I make my own?

[Greybeard]

Mike, if you know what a rose engine is, I'd guess you have it in you to build a cross feed yourself !
I'd suggest a quick look at a catalogue of modelmakers stuff. That will bring you up to speed on what is necessary.
Essentially, a means of holding the tool in a small mount, and having the facility to make this travel along the bed to give you a smooth cylinder.

Still keeping the size in mind, a small cross feed vice (screw feed allows you to move the work piece in two directions, normally used under a drill)clamped onto the lathe bed might be the simplest, quickest and cheapest way to do it.

John

[Mike N]

John, thanks, you were a great help

Mike

[Greybeard]

Glad to help, Mike.
If you want to pursue this further, send me a pm and I'll switch to email, before I lose my job as a moderator for being so off topic :)
John