Remounting between centres

[marcros]

I am not a turner but have a lathe and plan to learn.

I have just about finished making a bench but am toying with the idea of building a thickness sander attachment as part of it. I have the idea in my mind of how to do it but the critical part is repeat ability for the setup. Crucial to this is being able to remount the drum (approx 125mm diameter and 450mm long). I have a live and drive centre and a steb drive centre. I am not against buying some other bits if required.

1. If I turn it between centres, how accurately will I be able to remount it?
2. Is there a better way then mounting between centres for this task?
3. Any suggestions for drum material- it MUST remain true over time. It also must be able to have self adhesive Velcro stuck to it and have a good bond. Cost is a consideration.

I want to use the thickness sander on veneered substrate- the veneer is 0.6mm so the thickness sander needs to be pretty spot on after initial truing.

If necessary I could mount a drum on a metal shaft but holding this at each end is an unknown to me.

Thanks
Mark

 

[RogerP]

When turning metal, and to enable accurate remounting, I the mount the piece between two live centres (or dead centres) and drive with a lathe drive-dog.

I don't know if it could be applied to wood turning but I don't see why not.

 

[SteveF]

450 is quite long....will your lathe take it
i would make it in small sections...maybe even plywood
u could then use a compass to mark it accurate before turning
getting something that long "perfect" would be impossible for me unless done in sections
if done between centres you would then have dimples either side to drill it through

Steve

 

[marcros]

The lathe will take it- I think it will take 36" between centres. As long as it is reasonably even, I could true it up with sandpaper and the table that will become the bed of the sander. The more even it is, the less there is to sand off.

Plywood could be an option, sections not a problem.

 

[Dalboy]

I know this ONE is not on a lathe but it may help with some info

 

[YewTube]

As long as it is reasonably even, I could true it up with sandpaper and the table that will become the bed of the sander.
Plywood could be an option, sections not a problem.

I would use the Morse taper at the headstock as the drive.

Get a 12mm diam bar (or greater) to the length you need.
Centre drill each end.
Get an 8mm Morse taper drill bit and fit in headstock and drill a hole axially in one end of the bar. Make it 25 mm deep or as deep as you can. Use a revolving centre in the tailstock to keep it aligned.
Once you are happy with the depth of the hole then take the drill bit and cut off the pointy end so that you have a stub to fit in the hole you have just drilled. Glue/epoxy/weld it in place.
You should now have a bar that can be repeatably remounted between the headstock Morse taper and tailstock revolving centre.
It is not a problem if it wobbles slightly as once you have clad it with plywood/MDF discs and trued it, which I see you sussed from your comment above.

Bill

 

[flh801978]

Mark
I wouldnt underestimate the accuracy you need to be able to control the drum to 1mm never mind sanding a veneer thats only 0.6mm thick
I would make it out of aluminium thick walled tube say 6-10mm wall thickness
make plugs for the ends and perhaps one or two in the middle
Insert shaft of choice and then true up in a lathe as one

All metalworking lathe work though
I think I may have a suitable motor as well if you still need one

I'm happy to do all that for you if you wish

Ian

 

[marcros]

I know this ONE is not on a lathe but it may help with some info

That is the one that I had in mind before thinking of using the lathe.

 

[flh801978]

Here you go mark
find someone in HW to collect saw up into 24" lengths and post to you?
http://www.ebay.co.uk/itm/Aluminium-Tub ... 2edb1a5e5a

 

[flh801978]

If you do go for that I'll go halves on cost and postage? for half of it

 

[marcros]

i will have a look into it, but might be more hassle than it is worth. It is the "finding somebody" that is always the issue in these cases.

I think that I have the motor sorted although I am still not sure whether to utilize the lathe add-on, or make the one in the plan. The one in the plan has been used by the author, so whilst the tolerances are tight, it is possible. It is also entirely dependent on the flatness of the table, since this trues up the drum.

 

[Dalboy]

To be honest if you build a purpose built one then there is much less chance of errors creeping in than keep taking it off and on the lathe and having the worry of getting it centred every time.
I have a 1450rpm motor from a scrollsaw which I am going to make either the drum sander or a disc sander

 

[geordie]

rather than mounting between centres why not fit a face plate and use laminated mdf

Geordie