HV-6 Rotary table fixture plate build

[WobblyHand]

Recently bought a 6" Vertex Rotary Table, the HV-6. Made some tee-nuts to fit the table slots. Also blued the tee-nuts. Yesterday, received an 8" diameter 0.85" thick piece of 6061 for the fixture plate. The day before, I received an MT2 soft arbor, to act as the position locator.

While I was waiting for the HV-6 to arrive, I designed a fixture plate for the table. From the dimensions of the table, it seemed that an 8" fixture plate would fit on it without fouling. So made a design in FreeCAD for the plate. Here's a top view.

Nothing too fancy, but since it is a radial design, I will need to drill the holes while mounted on the table. Anyways, today was the day to start machining the plate. Managed to just barely fit in on my 6" four jaw chuck on my Grizzly G0752Z/G0602. There is maybe 1/8" clearance between the edge of the jaws and the ways. Really made me think if I wanted to try this.

Screwed up my courage, hand rotated the chuck, checked all four jaws for clearance, set the speed for minimum, and turned on the lathe. Faced off both sides so far. Honestly, it was kind of scary since the second face was pretty uneven, and the cut thumped. But, I took it slow, and trued up the faces. Used some TCGT inserts which cut aluminum beautifully, if I do my part. Once the faces were true, I took a finish cut. As I got closer to center, I sped up the lathe some to improve the finish. I was nowhere near the recommended cutting speed since I was a bit concerned about those chuck jaws, but the sharp edged TCGT inserts seem to be tolerant of SFM. I wasn't getting nice chips, but they were manageable if I repetitively paused during the cross feed. Since this is a manual lathe, and my hand gets tired after a while, it worked out fine.

After lunch, have to figure out how to get the tool close enough to chamfer the edge. Once that is done, the next step is to drill out the center, and bore it to 30 mm. Hoping that goes smoothly.

 

[WobblyHand]

Played around with the setup and chamfered off the edge. Was easy. Drilled out using a 1/4" drill, a 1/2" drill in the drill chuck in the tailstock, then went to MT2 drills in an MT3 adapter. Jumped to 7/8", and then to 1". Photo while cutting using 7/8" drill.

At 1" ran out of drill and time for a boring bar. Since this lathe is new to me, I hadn't made a bushing to fit my 1/2" boring bar to the 3/4" AXA-4 holder. So I had to fix that. Actually, I had drilled and reamed the bushing two days ago, but hadn't gotten around to slitting the bushing. Here's the bushing being slitted on the mill.

Yes, that weird stuff on the spindle light is plastic wrap. I was having troubles with chips sticking to the light. Thought I'd try this to see if this would make future cleaning easier. Now back to the lathe and fit up the boring bar. Came out nice. Snug down the screws and it is ready to go, but my lathe isn't quite ready. Don't have a quick change gear box, so I have to change the gears. I want a slow feed for the boring. Wouldn't you know it, I had brought up the manual from the shop. For the life of me, I can't remember the base setting for feeds. Oh, well, time for a break.

 

[mikey]

Just feed by hand. No need for power feed.

 

[WobblyHand]

I get a nicer finish with power 0.0025"/spindle revolution feed. Anyways, I did change over the gears to non-threading mode. Grizzly sure did choose a design that is a pain in the posterior. Idiotic e-clips that either fall off the lathe (three times!) or fling themselves into oblivion when removing them. (Had to get that out of my system! Thanks for humoring me.)

Came out at 29.98 mm on what I thought a finishing pass would be. So squirted in some WD-40 and ran a second pass, (same setting on DRO) and nailed the 30mm bore. Was thinking deflection. Don't have a metric 25-50mm micrometer, only a 1"-2", but I did get the decimal equivalent of 30mm to the tenth.

If I had a 30mm mandrel, I'd do a finish pass on the outer diameter. How do you make one? In particular, how does one make the expander?

 

[jwmelvin]

For an expanding arbor, I’ve done a flathead machine screw in a countersunk hole, then split with a bandsaw. The threads went deeper than the split.

 

[WobblyHand]

For an expanding arbor, I’ve done a flathead machine screw in a countersunk hole, then split with a bandsaw. The threads went deeper than the split.

So something like this? I don't have a bandsaw, only a slitting saw, so I can't go too deep. Each cylinder is 25mm long. Small cylinder is 30mm diameter and has a clearance hole for a 1/4-20. Bottom cylinder is 1-1/2" diameter (38.1mm) and will be tapped for 1/4-20. Material is 1045, since I have some stock. Slits are 3/4" deep. Aluminum disc to be clamped has 30mm hole and is about 0.75" thick. Counterbore isn't drawn correctly, but it is close.

Drawing that was kind of fun.

 

[jwmelvin]

Yes something like that should work if you keep the diameter right on the bore to be held.

For something like this where you just want to do something quick on the OD, I’d provable just make a mandrel with 0.001” slip fit and pressure turn (held on the mandrel with pressure from the tailstock.

 

[WobblyHand]

Well, I got this far on the mandrel... Right at 30 mm in diameter. Which means the plate doesn't quite fit.

Then heard a sound. Didn't sound too good. Stopped the lathe. Found this

Maybe that is why the e-clip kept falling off yesterday. Might of been a victim of over-torquing. Big sound was because I found the two gears had fallen off the bracket. Fortunately they fell in the chip pan. You can tell which one - its the oily one.

Hmm, slightly out of commision now. Got to order some dinky little parts to get back in business. Minor setback.

Guess I can still sand, shave off a tiny bit to get the mandrel to fit. Once that is done, I can drill it and put in a countersink.

 

[jwmelvin]

Guess I can still sand, shave off a tiny bit to get the mandrel to fit. Once that is done, I can drill it and put in a countersink.

That’s too bad about the gear mount.

If you are planning to split the mandrel, then I wouldn’t worry about taking any material off. It will compress to get the disc on. If you were planning to hold the disc on with tailstock pressure, you may need to file the mandrel a little. Or warm up the plate to slide it on and press off once done machining.

 

[WobblyHand]

That’s too bad about the gear mount.

If you are planning to split the mandrel, then I wouldn’t worry about taking any material off. It will compress to get the disc on. If you were planning to hold the disc on with tailstock pressure, you may need to file the mandrel a little. Or warm up the plate to slide it on and press off once done machining.

Not worried about the gear mount. Another two on order, $5 part. If I was desperate, I'd make one. I do have an operational mini-lathe.

Yes, thought I would try slitting the mandrel. The fit is so tight now, that I could sort of bang it on with a dead blow. Not sure I'd be able to get it off though.