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

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AdeV:
Well, another couple of steps complete, and it's just that little bit nearer to being done :thumbup:

First job today was to make the second piston. No action photos, I'm afraid, you've seen it all before I'm sure. At least I got all my radii right today :lol:

Now, before I go any further, I owe an apology to a fellow MadModder - I don't know who unfortunately, because I can't find the post in question websterz - because a few posts back, I pooh-poohed the idea of using a retaining pin, drilled up from the base of the QCTP which I saw in his thread. Well, I hereby eat humble pie & apologise - because all my grand ideas of tapers and/or flanges went out of the window, and I've ended up with, yes, a pin going into a slot in the bottom of the piston:

The hole is drilled 3.5mm, and partially tapped M4 for a grub screw. The slot in the bottom of each piston is 3mm (I lunched one of my 3mm cutters too, oops). If you're really sharp-eyed, you might spot the cock-up in this picture... The "grub screw" is just a cheap-ass M4 bolt with the head cut off, and a screwdriver slot cut in with a hacksaw.

I didn't have any 3.Xmm material, the smallest stock dia I've got is about 5/8". Rather than waste 95% of that, I ended up using a section of the handle of a deep fat fryer basket (the basket will appear later). My chuck won't handle anything smaller than about 5/8", so I put the ER32 collet chuck in the 4J & dialled it in to within a thou or two. Popped the stainless (?) bar in, with about an inch & a half stuck out, and proceeded to make some cuts. This is all new to me, I've never lathed anything this small before.... so I bent the first one trying too big a cut (& then trying to rescue it, didn't work); I was more circumspect after that:

And so.... it was time for the moment of truth.... with all machining operations on the main body now complete, it was time to try to black it. Earlier this week, I handed 85 of our queen's heads over to Caswell Europe, who in turn sent me a bunch of chemicals:

They didn't send any coffee though, I had to make that myself. :lol:

And....

...that's it for now! I've run out of time & have to go out.... the rest of this update will be along later this evening. Sorry about that!

raynerd:
Wow - 85 squid is a good bit of brass...look forward to seeing the results. It looks amazing so far!

AdeV:
And back... sorry about leaving y'all in the lurch there, but, duty dinner called ::)

Chris - I thought long & hard about the stuff I bought; price wise, it is the most chemicals I could get for less than £100. It should last me for months, and that's even if I gratuitously blacken stuff I make. The solution is good for 4m2 apparently; I don't know how much I used today, but if it's 0.1m2 I'd be amazed.

So, having poured/diluted the chemicals - as applicable - into the 4 plastic buckets, and having pre-washed the block in fairy liquid as recommended (in the absence of a hot degreasing solution), it was time for the 4-tank-shuffle... First, degreaser:

Then conditioner, then the cold-ox stuff itself:

As you can see, it started to blacken immediately. Telling when it was done proved difficult; in fact, I over did it a bit & it started making "soot"; the trouble was, the soot rubbed off & it looked grey underneath... Visions of failure swam before my eyes.... leaving it in a bit longer just made it worse, so in the end I gave up & followed the rest of the instructions, rinsing the soot off under the tap. Then, into the sealer oil:

Handy thing, that basket... it came from one of the deep fat fryers I bought to make machinable wax (remember that stuff?)... I left it 1 hour that way up, then turned it over & left it another hour and it STILL wasn't dry (the instructions said 45 mins to 1hr - that must be for small stuff), so I cleaned it up with a paper towel...

So, how does it look? Well, I put it all together, and...:

Eee, just like a bought one :D

In normal use, the piston should stick out this far (RH piston):

If I make a shabby tool holder, it will come out this far:

Let's face it, that's just an excuse for more pictures. So..... got the base to make, and the central pin that holds it all down & locks it in position. And then some toolholders, and it'll be ready.... Onto the home stretch now, I feel :)

Powder Keg:
Looks great!!! I've been thinking about their nickle plating setups.

Bernd:
That looks to nice to be covered in swarf or even to put on the lathe and get scratched. :D

Bernd

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