[philbur]

Nobody has mentioned tolerences on the hex yet. I think a snug fit in the socket is going to require tight tolerances and repeatability. I think horizontal with a 4th axis would be better in this repsect. Rotating should give you +/- 0.01mm and there is no other dimension critical movements to make when machining each flat.

Phil

[philbur]

Also horizontally you don't have any centering issues. Once you get the Z-axis height correct (with a couple of test runs) you are in business.

Phil

[justgary]

Philbur speaks sooth. I think that I would still consider grinding, but supporting a horizontal milling operation with a grooved block in your vise would make it easier to control.

You'd have to diddle around with the block to get it set up correctly, but I think that the whole point of either method is that once you get something set up (horizontal or vertical), you could make a decent run of parts pretty quickly. It's the one-off stuff that will kill your time like nothing else can.

Regards,

- Just Gary

[Magnum164]

Yea getting an idea of the time involved as well. I am looking to get an order up on the tools I need so will look into the grinder. I did buy the HSS, not sure if that would work for grinding.


And Phil, no haven't considered the tol that will be needed yet but I do know I hate getting hexes that are not a snug fit.

[philbur]

With 10,000 rpm available on the main spindle I would try a small cup wheel with no tailstock support of the workpiece with the tip already heat treated. If you have only 4 or 5mm overhang from a collet in the 4th axis I don't think part deflection will be a problem. Do a roughing cut to take all the material in a single pass then a back pass to take any spring in the workpiece. Assuming the process works then the first one would take you 30 minutes or so and then additionals (at the same size) will take only a few minutes a piece. With grinding you may need coolant to avoid losing the heat treatment of the tip.

If the deflection is to great, or you lose the heat reatment, then you could make the cut in multiple passes with repeatable z-axis positioning to a few tenths using a DTI from the head to the table.

In the end it's going to take you much more time to work out how to do it and set it up than it will actually take to do it once you have the correct process.

Phil

Yea getting an idea of the time involved as well. I am looking to get an order up on the tools I need so will look into the grinder. I did buy the HSS, not sure if that would work for grinding.


And Phil, no haven't considered the tol that will be needed yet but I do know I hate getting hexes that are not a snug fit.

[justgary]

Magnum164 -

With a grinder, you can also just touch off the stone on your part, especially if you intend to grind the tip profile as a last step.

Just move the wheel just over the tip of the work, start the spindle, and bring it down one step at a time. You have found the radius of the part when you hear the grind wheel contact the part. The radius is actually somewhere between the step that didn't touch and the one that did, but using the one that touches will help you get a slightly negative tolerance. Whatever method you use, you'll want to play around a little to make sure it is repeatable.

If you use a large enough wheel you can reach right up to the collet in your 4th axis. If you use a smaller one you'll have to support the end of the work since the spindle won't get close enough to the 4th axis. By far it is better to get a slightly larger wheel and work next to the collet. Just make sure to not exceed the maximum RPM of your wheel.

Regards,

- Just Gary

[Scott_M]

Not sure which 4th axis you got 6" or 8". There is no collet setup for the 6" and the 3-jaw for the 6" will not close down to 2mm. I have the 6" and just checked my 3 jaw the smallest pin I could get it to hold was .092".
So there may be some fixturing involved to use the 4th axis.

Scott

[Don Clement]

"Not sure which 4th axis you got 6" or 8". There is no collet setup for the 6" and the 3-jaw for the 6" will not close down to 2mm. "

It is possible to use a 5C hex collet holder in a vise and index by hand. see: http://www.fastenal.com/web/products...ex?sku=0344213

I have used the hex and square collet holders in a vise for quick indexing when I don't want to get the 8" RT with 5C chuck out.

Don

[Magnum164]

"Not sure which 4th axis you got 6" or 8". There is no collet setup for the 6" and the 3-jaw for the 6" will not close down to 2mm. "

It is possible to use a 5C hex collet holder in a vise and index by hand. see: http://www.fastenal.com/web/products...ex?sku=0344213

I have used the hex and square collet holders in a vise for quick indexing when I don't want to get the 8" RT with 5C chuck out.

Don

Hey Don, yea I was going to say I have the 770 so the 8" will not work (or not recommended) but I do have the 5C adapter coming in for the 6" table which I thought I could get some collets for. Will check out fastenal as I need to order a good set of end mills and other tools.

[philbur]

What's wrong with using a 2MT collet in the 6" rotary table.

Phil

[Don Clement]

BTW I also have a manual 6" RT. Before getting the Tormach 8" RT I had the Bison 5C collet chuck mounted on the manual 6" RT with a homemade adjust- a-chuck mounting to eliminate most collet chuck runnout. My 6" manual RT looks very similar to Tormach's so I believe the same Bison 5C collet chuck could be mounted on the Tormach 6" RT. Also in addition to the 6” & 8” RTs I have a phaseII 5C indexer See: http://www.phase2plus.com/details.as...ET_INDEX&id=15
Note that Haas started by motorizing an indexer similar to the PhaseII. See: http://www.haascnc.com/about_history.asp#about

Don