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| Another new project... a QCTP (Quick Change Toolpost) |
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| AdeV:
Work had me working late tonight, so shop time was curtailed :( I made a start on the base, however.... Since my vice doesn't seem to be well dialled in, I got rid & worked straight on the table today. First up, line the base up as best as possible (it's already been hacksawed to size): Then trim the two accessible edges; jiggle the clamps about a bit (i.e. add an extra clamp, move the other two around, one at a time): It's now square to within a thousandth. Take that, cheap chinese vice! I then had to disassemble the top of the lathe to get the old toolpost off, to find out what spacing the mounting points are... 3" for the record. So, drilled & tapped two holes in the base to mount it. I also centre-drilled the middle of the base, as it will need a threaded hole cutting in it (size TBA), not to mention relieving (on both sides! - the underside because there's a ring sticking up where the old toolbase sat, and on the topside I need to leave a circular upstanding piece for the new toolpost to ride on... Anyway, just for laughs, I decided to take a "preview" shot, of it sitting on the lathe: Hmm, it looks a bit high.... Ah, that's because it is: Centre height is about 0.450" below the bottom of the piston :( I plan to relieve the base a bit, so that will claw me back about 0.200" of height, and I could (in theory) skim about 0.400" off the bottom of the block; but for now I think I'll just leave it & see how it pans out. If I have to do something about the height, I may also make an entire new cross-slide, as mine is badly worn... |
| AdeV:
A touch more progress today... First - after putting the lathe back together... - mount the base plate in the chuck, centering on the hole I made yesterday, pin the piece onto some parallels for straightness, then drill to 8.5mm, before power-tapping M10 at 60rpm: These HSS spiral point taps really do work very well... Now, cut a relief for the circular thingy that will be left on the cross-slide (the current toolpost uses it as a guide, but the hole in my t/p is too big for it). This was a proper arse-puckering procedure... last time I did this I wrecked a parting off tool, destroyed the piece I was cutting, and quite possibly damaged the chuck too... so, lots of very slow feeding, take it down to 0.100"; then another 1/2 width cut just to make sure. The following photo is posed - no way was I going to take a photo while it was all spinning: Then, turn the piece over & mount on some bigger parallels. I originally took the parallels out after I set it all up, but the first interrupted cuts pushed the piece very slightly off-line, so I had to leave the parallels in & squish it all tight with the live centre - I bet that did its bearings the power of good... not: The idea here is to cut away about 0.100" again, leaving the central section for the toolpost to ride on. It took a while, I had to keep the speed & feed rates right down, it was interrupted cuts almost all of the way. Anyway, after 0.100" was done, I did a touch of filing on the lathe, and some more off the lathe. It's not finished yet, so no more photos. There's another problem too: Look at the last photo in the previous post, and you'll notice a touch of discolouration on the black top. Today, it was worse: Aargh! RUST! Damnit! That block has sat, naked, in the workshop for weeks on end, with nary a smidgeon of rust on it. 2 days after I blacken it, it looks like THAT! Curses! I can only assume I didn't let it sit in the water-displacing oil for long enough, and/or a bit too much water soaked into the steel (yeah, you might think it was waterproof, but it's not: Just play an oxy-acetylene flame over some steel & watch the water dive out of it). So, I baked it at 90 degrees in the toaster oven for a couple of hours, then soaked it in WD40. If it still looks OK in a couple of days I'll call it done; if not, it's out with the sandpaper, and I'll have to re-black it. Grumble. Next task: The central pin which clamps the toolpost down to the base & also acts as a retainer for the offset-cam. So, I cut some stock off my 2" bar of EN1A-Pb (leaded steel), and curse it if it wasn't too short. Grumble grumble mutter grumble. So I cut a longer piece off, I'll make that bit tomorrow now. |
| raynerd:
Looking mighty cool AdeV - nice one! |
| Brass_Machine:
--- Quote from: AdeV on September 12, 2010, 05:35:20 PM --- Eee, just like a bought one :D --- End quote --- Ade, That came out fantastic. Now... could you do a write up on the finishing (blackening) process?? Eric |
| AdeV:
Hi Eric - I did cover the process briefly in the post you quoted that picture from; but sure, I could put together a proper "full explanation" type post together if you like. I may have to re-black the toolpost anyway... after the rust incident, I baked it for a while then slapped lots of WD40 on it; that seems to have done the trick (for now), but some of my other experiments involved fine wet&dry, so I've actually scraped some of the black off one side.... We shall see. Anyway, it's time to hit the workshop for a couple of hours, be nice to get this one finished off... |
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