Workholding advice.

[marcros]

I am making a skeleton clock and am struggling with thinking out the process.

I will be starting with a 50-55mm thick blank. I need a finished size of 45mm so not much to play with, but it is flat at the moment which helps. I will start with a 200mm blank, true it up and need to create a 150mm hole in it. It will become a thick walled cylinder. I don't have chuck jaws anywhere near that size and it would be useful if I could keep most of the centre.

What I was wondering about was to glue the blank around its edges to either a man-made board or some cheap softwood. I could then attach this to my standard chuck jaws or a faceplate. Am I thinking along the right lines?

It would enable me to remove the centre, and fully finish the item with the exception of the glued joint whilst it is on the lathe and backing piece . The last bit may have to be done off the lathe but it isn't a big job.

I don't have any remounting jaws.

 

[Robbo3]

Yep, it's called a g̶l̶u̶e̶ ̶c̶h̶u̶c̶k̶. Basically you are gluing on a tenon.
Presumably you will have a centre mark on the workpiece. If not, make one. Drill a small centre hole through your tenon. I do this before turning it, then use a nail, or similar, through the hole to align the centre. marks.
Choose a decent glue & allow it to set overnight. If you sandwich a piece of newspaper in between, the joint can be split by tapping a blade down the paper line.
Edit: glue block

 

[Lazurus]

See Lyle JAMIESON on You Tube he uses this method on every bowl with super glue, I was skeptical at first but often use this method, easy and effective.

 

[Robbo3]

Sorry, it's a glue block although I have heard it called a glue chuck.
A Youtube search for 'woodturning glue block' brings up a number of videos including Lyle Jamieson
- https://www.youtube.com/watch?v=y8b35iq4LTA
- https://www.youtube.com/watch?v=Yv26HJQxp3U

 

[Phil Pascoe]

A hot melt glue gun is your friend.

 

[marcros]

:mrgreen: I knew that you were going to say that Phil! :mrgreen:

would you hold the blank to a ply backing, and run the glue around the joint, or try to sandwich glue between the blank and the ply?

 

[Phil Pascoe]

You can put a few blobs around the outside, you'll be surprised what it will hold. It's easier to get off, and often you can turn through most of it. If you use it in between put a few bits of card or some sort of spacer between the blank and the backing first to allow a hot putty knife or something similar access - if there isn't a tiny gap you'll never get it apart again. DAMHIKT.