Another new project... a QCTP (Quick Change Toolpost)

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AdeV:
After hmming and hahing for a while, I decided what the heck; clean up the bore & consider it done. So, I set to with the wet & dry, but got bored after a while, and my fingers hurt.... so, I had a brainwave. (It'll end in tears -ed)

I figure, a tumble polisher tumbles various steel (or whatever) parts together, ideally with a lightly abrasive medium. Well, I didn't have any abrasive medium handy, but I did have a handful of mixed nuts:

I figured, the nuts being harder than the bore, the bore should be the one to take the wear. With enough knowledge to be dangerous, I tape up the holes:

And sent it for a spin:

After a couple of hours, and with more than a little trepidation, I opened her up for a look:

Not bad! Not perfect, some abrasive stuff would probably help. So, I chucked some extra nuts I'd found in, sealed 'er up & set 'er off again. A couple more hours later:

Not much difference. I think I've reached the limit of what I can do with my nuts. I think I'll move onto the cam next, see how far I get with that...

AdeV:
One last photo for today:

As you can see, the new toolpost will stick forwards of the old one a little way, even before I add any tool holders... therefore, I might push the dove tails back 1/2", to give me a bit more breathing space by either dovetail.

Hopefully, I'll have some time in the shed tomorrow, before I swan off for 2 weeks. Don't think I'm going to get it finished before I go away somehow...

Edit: Does anyone have a large (BXA?) toolpost? If so, can you please measure the dovetails (widest & narrowest parts)? I've googled & googled and I can't find a single reference to the _actual_ dimensions of these toolposts... It occurs to me, if I make my dovetails the same size as a commercial item, at least I could buy toolholders instead of having to make them, should I become lazy and rich in my old age...

Divided he ad:
Can't believe you used your nuts for that!! :jaw: :lol:

I'd have thought that the centrifugal force would have kept them all to one side? How fast was it spinning?

Doesn't a tumble polisher move slowly with as stated "abrasive stuff" doing the work over many hours?

Just wondering.... Never tried it myself.

Looking good though Ade :thumbup:

I'm no help what so ever on the technical dimensions question though sorry ::)

Ralph.

jim:
just a thought on this polishing the bore, why not chuck some bits of grinding wheel in with the nuts??

Bluechip:

--- Quote from: Divided he ad on August 15, 2010, 07:33:49 PM ---Can't believe you used your nuts for that!! :jaw: :lol:

I'd have thought that the centrifugal force would have kept them all to one side? How fast was it spinning?

Doesn't a tumble polisher move slowly with as stated "abrasive stuff" doing the work over many hours?

Just wondering.... Never tried it myself.

Looking good though Ade :thumbup:

I'm no help what so ever on the technical dimensions question though sorry ::)

Ralph.

--- End quote ---

Bit :offtopic: but, as I made a couple of tumblers as a lad ..

They do run quite slowly, about some 60 - 120 RPM is typical for a 4-6" drum.

If you want a cheap abrasive, get some 'Sharp Sand' from the DIY shed/builders merchant. NOT soft yellow/red building sand, that's useless.
Sharp sand is nowhere near as good as Carborundum grit, but it's nowhere near the price either. ::)
Use it wet with a dash of liquid soap.

'Many hours' Ralph ??

Days or weeks for pebble polishing :(

Nice shiny nuts though. Mine are rusty. I'm jealous ... :lol:

Dave BC

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