The Craftmans Shop > New from Old
The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
awemawson:
Yes I gave that approach serious consideration before I started trying to flatten the damaged bit, but frankly the whole thing is distorted. I assume that it came into contact with the tail stock sometime in its history.
I'm going to try and make a drawing of it and see if I can work out a bending plan. I suspect it'll be easier to make several sub assemblies and braze / spot weld them together. Looking at it, the original is made from two bits fixed together but increasing to four or five will help.
awemawson:
The plan today was to measure and draw up a model of the cover, print it on paper, glue it on card, and try it. That plan fell by the wayside as I tried juggling multiple A4 print outs.
Hang it I thought, plot it on the CNC Plasma Table tying a pen on it - then, no hang it just cut it :lol:
So I measured up the first part of the cover - the rectangular part that actually covers the belt - zapped it into Sheetcam and cut some steel, bent it up, then realised I'd marked and bent on the wrong side - it's inside out :bang:
Never mind, it'll be a practice piece for when I MIG weld it up .
Second cut on the CNC plasma table, then bent it the right way this time :thumbup: I see I've got the angle of one lug slightly wrong, so I've corrected the drawing but I don't actually think it matters much - anyway I could patch a bit in when welding up if it proves fatal.
Trying it out on the machine it fits at least as well as the original - no fixing holes yet so just wedged in with a screwdriver ! NB This one is 10 mm longer than the original to give extra clearance for the pulley hub.
So I think it probably is feasible for me to make another cover, it just might take a few iterations :lol:
awemawson:
I did actually make a third one incorporating the missing bit and then started on the second section. Just a strip folded with some interestingly close together folds that involved modifications to the folder.
Fit up is not fantastic, but it should be OK for MIG welding if I can remember how :scratch:
Just the last little triangular bit to do now which probably is best done when the rest has at least been tack welded.
awemawson:
Time to glue it all together. I dug out my Migtronic KDX 250 MIG welder that is loaded with 0.6 wire but try as I might I could not get it set up. The 'burn back' circuitry and control don't seem to be working - something to fix when a RoundTuit comes along ! So I had to resort to the Butters AMT 3205 which is loaded with 1 mm wire and better suited to welding 6 mm plate.
So a few practices on offcuts and also the prototype cover that I bent up inside out, showed that with care it was possible, but mighty easy to blow a hole - this welder cheerfully blows hole in 6 mm plate !
Quite a bit of tacking a bit, bending to shape, tacking a bit more until there was enough done to try a test fit. Not too bad at all, just a trim off one edge. Then I had to create the triangular feature. The original cover was rather distorted, and a packing piece had been fitted to jump a gap, so by a little bit of re-design I was able to get a reasonable fit without the packer.
Then it was a case of grinding back the welds - not all the internal bits are accessible to the grinding disk but I don't suppose it matters much.
Then numerous fitting and removing and marking and drilling and fitting and marking . . .well you get my drift . . it was great fun transferring the holes from the turret onto the cover. I couldn't just copy the original as not only was it distorted, but the new cover leave 10 mm more clearance for the powered tooling pulley (which was where all this began !)
Eventually all screws were able to be fitted, and now it needs a good final clean up and a few coats of paint.
tom osselton:
Nice job!
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