Today was the day!
I'd been holding off a couple of multi-hundred-part runs while I try to catch up on a handful of smaller ones, and finally caught up enough to start.
The trick here was that I needed to swap to a new tool set, since the one I'd been running these past few months didn't have the right ones. So I stripped out the previous set, and spent a solid half hour cleaning out the machine.
I then set up the necessary tools, and, since I'll be using bar stock rather than pre-cut pieces, I pulled the collet stops and looked again at the outboard end of the spindle.
The issue here is that I want extra support for the long bars (cut to 36") at the left end of the spindle, so they don't "whip" and cause vibration. The correct solution for something like this is called a spindle liner- a plastic sleeve that slips into the spindle bore, that more closely fits the OD of the stock.
The problem is, first, the factory-made spindle liners are over $200 each, and second, only go up to 7/8". And I'm using nominally 1" stock.
The last time I ran this part, I made up this little plug...
But it was only retained by that O-ring. The fresh batch of stock is very slightly larger diameter, and that collar no longer fit. And I didn't want to bore it out, since the thickness at the bottom of that O-ring groove was already very thin. What I needed was a way to hold the collar in, without that O-ring.
What I wanted to do was pull the drawtube and drill and tap the end face for a pattern of three holes or so, so a "top hat" shaped collar could be bolted in place, or a small cap/washer sort of thing could retain it.
Unfortunately I don't have snap-ring pliers big enough or powerful enough to remove the retainer. I need to buy a pair, since these pneumatic collet closers need periodic servicing, but for now, I need to get this ball rolling. I should have been running these parts months ago.
The only other option is those radial screw holes, meant to either retain a cap or plug (I use 'em to hold an adjustable collet stop in place) or to retain a long thin rod like a 4-jaw chuck.
Why not just use those to hold the bar stock? The end cap/plug/support also helps control some of the oil that travels down the drawtube.
So, while I will at some point pull that drawtube and drill and tap the end, for the time being I'll just throw a bodge at it.
To that end, after almost three minutes of noodle time, I found a likely looking hunk of 3" aluminum round, and sawed off a hunk about yea long.
That I chucked up in the Monster and hogged out a bunch of the extraneous meat...
And then switched it over to the Sheldon for the fine tuning.
I was playing it by ear, and after a quick test fit, realized something was minorly wrong, and adjusted my dimensions slightly.
That bit will fit over the end of the drawbar like so...
And when we close the access cover, you'll see why we needed that adjustment.
The inner bore of the cap was recessed to take a piece of 1/5" Delrin round...
Which was itself turned on the OD to fit the ID of the drawtube, and then bored out to snugly fit the OD of the bar stock.
That slides into the end of the drawbar, the stock fitted through that...
And the cap slid over the whole works.
Yeah, it's a bodge and convoluted, but it should work to get this job done. I still need to set up the indexing head and drill the bolt pattern, and dig up a set of matching screws that should hold 'er in place- as well as drill a couple of oil-drainage ports.
And somewhere along here I'll pick up a good set of snap-ring pliers, and re-do the whole thing, but right now, I got parts to cut!
Doc.
