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

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Divided he ad:
Looking mighty good Ade :thumbup:

Aluminium bronze!!! Tough stuff indeed :jaw: I've got a few lengths of 1'2" hex that Bogs got for me from the scrappy (not as expensive as yours) only made a torch from it so far, looks great when polished up but machining it wasn't fun!

I like your experiments into the blackening. Never had the resources or the room for such.... One day ::) Hope it all works out after handing over the hard earned for it?

One of these days I'll get over there again to visit and see all this stuff first hand eh?

Hope today went well?

Ralph.

DeereGuy:
Nice work!

AdeV:
Thanks Ralph & Bob - much appreciated. Ralph, I could use you popping over, I haven't the patience to polish it properly! :lol:

Anyway, tonight, I did a bit more. I needed to work on the central pin, that locks the tool holder to the base, whilst still allowing the cam portion to rotate. It also acts as a retainer to prevent the cam from being lifted out, should you be perverse enough to try such a thing... Anyway, I chucked up a 6" piece of 2" leaded steel, and got busy with the rough cuts:

The retaining ring diameter was 1.75"; having reached that, I cut the main section (1.5"), then the bottom section (1"):

The retaining ring is, as you can see, cut right up to the chuck. Annoyingly, and stupidly, I hadn't left myself a long enough section on the end to reach all the way through the toolpost & into the base. So a bit of lateral(ish) thinking required... I drilled & tapped the base for some M10 stud:

Then, using two bolts tightened against each other, I wound the stud in as far as it would go. Before I finish this off completely, I'll probably take the stud out again & loctite it back in, just to be sure it stays there forever. But tonight was all about making sure everything would fit together OK.

So - having inserted the stud, I moved the piece away from the chuck by 1/2", and parted it off, finishing off with a hacksaw. And so, finally..... all the major parts are finished, hooray!

And when it's all put together:

:beer:

Obviously, we're not quite there yet - I still have to do something with the top of the post. I had thought, drill & tap it for M10 or M12, and loctite in a cap screw, which could then be used to tighten or loosen it. Or I could make another handle thing, rather like the original plans suggested. I've yet to decide... However, what I will try and do, is finish the top off with some brass, just to give it some contrast with the stainless steel. As to how it performs; well, once I'd done a bit of file work, I can now clamp it right down hard on the base, and still turn the cam lock with only a little binding (I reckon some valve lapping paste & elbow grease will cure that).

Oh go on then, if you insist, one more photo.... An "exploded diagram":

Some final thoughts (for tonight): It would seem that my "rescue" of the rusting situation has worked. Basically, I stuck it in a toaster oven at 90o for a while, then whipped it out & drenched it in WD40. And that's pretty much it; the rust has disappeared, and the black surface remains - except where I'd rubbed it off with sandpaper :doh:

I will probably blacken it again at some point, but I'll see how it holds up in use before I do.

The next job, then, is to make a holder, so I can try it out...

AdeV:
Onwards!

More or less from the moment I parted off the centre pin, I wasn't happy. Feelings of unhappiness persisted through the night & into the morning... e.g. how was I going to tighten it down? Visions of drilling/tapping for a cap bolt swum around. Nah, ugly. Same with welding a bolt to the top, ugly. I can't cut hex holes, haven't got the technology.

Luckily, our next door neighbour here at the shed is a tame racing driver welder (Top Gear fans may make their own Stig jokes up now). So I cleaned the ends of the pin & the stump, and added a "fillet" (the chamfer on both parts):

Then my tame welder simply glued them back together:

Next, some quality time on the lathe, slowly trimming, tapering, parting off the excess, drilling & tapping for M10, and - some time later:

That's better! If you imagine the lathe ways coming towards you, perpendicular to the visible piston, that's where the top handle will be in relation to the tool block. It's a doddle to just back it off 1/2 turn, swivel the toolpost to whatever angle you need it, then scraunch it back down again, job done :thumbup: The only issue is, when it's really ground down hard, the cam binds up. I think it's because of the various centering/wobble issues I've had while turning, mean that the bottom of the central pin is actually a smidge off centre; and when wound down, it's being pushed into the cam spindle, locking it up too. It's not pushing down at the top, of that I am certain. All I need, then, is to find some valve grinding paste (Can I find any? Can I buggery. Halfrauds don't seem to sell it any more either.) & lap the cam in to the pin (or vice versa, it really doesn't matter which one takes the wear) so it turns a bit more freely. I don't mind if it's a bit stiff to turn, that should help prevent any liklihood of the thing undoing itself in the middle of a vital cut...

Bluechip:
Chemico Grinding & Lapping paste ..... got some from here last year .. then found the local car bits shop sold it ... bugger :doh:

http://www.frost.co.uk/chemico-lapping-and-grinding-paste.asp

EDIT It seems yer need to click the pic. Didn't buy 72 tins ... just the one ..

Dave BC

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