The Craftmans Shop > New from Old
The Sequel - Oh Blimey I bought a CNC Lathe (Beaver TC 20)
JerryNotts:
Its important to not become too hung-up on what you might see in patents. For many years I worked in a (British) company that patented almost everything that was thought of in its extensive laboratories. Part of the philosophy in that company and other R&D based companies was to issue so many patents for similar things that competitors found it difficult to work out which patents might apply to the item in front of them. Of course every patent could be backed-up by records showing how, if callenged, the patent was arrived at.
Jerry :beer:
awemawson:
I agree Jerry, but in this case nowhere else are there any drawings or descriptions of how the thing worked, and I've talked to three people who worked for Beaver maintaining these turrets. Even then drawings weren't available and they just had to muddle through and do what they could.
I think the patent description and drawings in this case are a fair representation of a slightly earlier, but VERY similar turret to mine, from which mine evolved. They have clarified quite a few details in my mind.
After a very short production run, as I understand it, they decided to buy in Baruffaldi turrets rather than make their own. This ties in with a history of Beaver's demise that I've read, where about this time they started outsourcing parts due to 'bean counter' pressure, as the Banks were calling in the overdraft.
awemawson:
I spent this morning altering a Post Processor for FeatureCAM to generate code suitable for the lathe. Not there yet but distinctly 'on the way'. I also spent some time investigating the commands for the Powered Tooling discovering little quirks like:
M24 S100 <LF> (M24 means start tool spindle, S gives it the speed to run at, <LF> is 'line feed')
Totally fails to spin the tool drive at 1000 rpm, and it creeps round VERY slowly
However:
M24 <LF>
S1000 <LF>
Works a treat :bang: No documentation on this, and these little things take AGES to find !
Now in retrospect the very slow rotation is because it still holds the speed command value from the last tool change, where the servo turns VERY slowly . . . but if you don't know . . . .
Then I went to more physical things for a bit of sanity. The door on the tail stock end that gives access to the tails stock handle has obviously had an 'issue' at some time, in that the tin work around it's opening was a bit bent, and the original door is missing. However someone has started to make a replacement, bent up from galvanised plate, with welded corners.
It's a bit of a rattly fit, the opening for the catch has been cut rather roughly, and it's been left somewhere damp, and not been painted. So the welds were heavily rusted. I attacked it with a rotary wire brush and sanding disk and it's slightly better now. The galvanising had gone all white and furry! I can't paint it until the piano hinge that I've ordered arrives - it'll need packing out side to side involving drilling holes, and that's best done before painting.
The catch - a Push and Turn from 'Southco, Lester, PA' must have suffered in the original accident, as it's body was badly squashed and a bit broken off one corner. They are still available, but it looks like this size (35 mm x 78 mm) has been discontinued. 21 x 45, 40 x 85, and 57 x 141 no problem - but not this one :bang:
A bit of judicious bending got most of the squash out, but this is thin Mazac so is just waiting to break - it'll have to do !
awemawson:
I decided to have another go at the cut out for the catch on the Tail stock Door. Remembering how well lead free solder works with galvanising I soldered up the 'over cuts' where he'd been a bit reckless with his cutting disk, then flatted it down with a sanding disk.
Now at least the remaining blemishes are hidden by the rim of the catch
awemawson:
Well I'm CHUFFED - though I say it myself :clap:
This evening I've managed to draw a simple cone in FeatureCAM, post process it with my tweaked and adjusted post processor, upload it to the Sinumerik 820T controller using DNC4U, AND have the courage to run it full wack no restraints :ddb:
Now to be honest first time I'd nobbled the feed rates and spindle speed to very low values and had my hand on the eStop button (as you do !), but then once proved I let it rip, and both the machine and I survived
Being 'constant surface speed' turning and a steep sided cone the chuck didn't half spin at a rate of knots at the smaller end of the cone.
The post processor code still needs breathing on and tidying up, but it's definitely on course.
I still need to master work offsets and tool offsets before I can actually make chips, but before I do that I need to invest in some 25 mm shank index-able tooling as most of my existing stuff is 20 mm.
Now having a 'rear' tool turret and some VDI40 holders that jack the shank to the top of the slot and others that press it down, I need to standardise and make a few decisions. It affects the handedness of the tools and the direction that you spin the chuck , CW or CCW. I need to find a quiet hour to get my head around the variables without the usual interruptions of life.
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