[Nelson_2008]

I just measured the bore of this Vertex 6" table for runout, and I'm getting about 0.0015" (peak to peak reading on a dial test indicator which is against the wall, about 1/8" below the table top).

I'm not sure if my measurement method is correct or not.

Anyway, according to the spec. on the table, the max runout is supposed to be 0.02 mm (0.00079"), and the test sheet that came with it claims it is 0.01 mm, which is kind of hard for me to believe.

[SCzEngrgGroup]

I just measured the bore of this Vertex 6" table for runout, and I'm getting about 0.0015" (peak to peak reading on a dial test indicator which is against the wall, about 1/8" below the table top).

I'm not sure if my measurement method is correct or not.

Anyway, according to the spec. on the table, the max runout is supposed to be 0.02 mm (0.00079"), and the test sheet that came with it claims it is 0.01 mm, which is kind of hard for me to believe.

0.0015" peak-to-peak is less than +/-0.00079", which is 0.00158" peak-to-peak, so where's the problem?

Regards,
Ray L.

[Nelson_2008]

Well maybe it's not a problem, but they claim this particular table tested at 0.01 mm which is almost half of what I'm measuring, right?

(Also I just checked the data sheet for the other table, and it says the same thing, i.e., tested at 0.01 mm. Based on what I've seen already with these tables, I wouldn't be surprised if they're just pumping out data sheets using the same numbers).

Mainly I'm wondering how my measurement of 0.0015 peak to peak (and it might actually be a little worse, say 0.00175 or so) compares to a 6" Grizzly or Phase II or any other brand for that matter.

[SCzEngrgGroup]

I would not put a lot of stock in the test data....

For a rotary table, I would think that would be pretty good. Spec on the PhaseII is max 0.0008", and you are under that.

Regards,
Ray L.

[bogiestl]

Table by itself, or what you've bolted to the table?

Have learned a lot about chucks recently... Getting ready to order a set-tru clone, should give me about 0.0005ish with a little effort.

[Nelson_2008]

I was interested in seeing actual measurements from other 6" rotary tables - by themselves - just so I could see how this Vertex table compares.

I do have a 5" 3 jaw, front-mounting Vertex chuck for it, but I didn't try bolting it to the table yet. When I do, the first thing I'm going to do is check the runout.

BTW, what size set-tru chuck are you getting and how much does something like that cost, if you don't mind?

[wizard]

At least for spindles it is. This being a rotary table I would think the same logic would apply.

Assuming a morse taper I'd shove a decent drill bit into the taper and see what you get on a clear portion of shank. I'd also think real hard about your test setup. Ideally the indicator and stand should be fastened to a common mounting surface with the device under test.

From personal experience I've learn not to jump to conclusions about "bad" indicator readings. You need to develop confidence in your setup and the actual devices being used to take the readings. Especially when measuring in a bore and stylus tip orientation isn't optimal.

[Nelson_2008]

I had the rotary table bolted to the milling machine table, and I had the dial test indicator held in the milling machine chuck.

Anyway, I found something I did wrong. I looked in the bore and it looked clean, but I decided to clean it with some WD40 and a toothbrush, then I wiped it out with a rag, and measured it again. And after doing that I'm getting better numbers. Now I'm getting, at worst, maybe 0.0012" peak to peak, or something like that.

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Edit:

For a few weeks now I've been trying to find a blank MT2 arbor, not only for testing purposes for this rotary table, but to help center the chuck on the table. For some reason the only ones I can find are on Ebay, but they're in the UK. Does anyone know where to get one in the U.S.?

[Geof]

....I looked in the bore and it looked clean, but I decided to clean it....... I'm getting better numbers.......

Now you have discovered how thick a film of oil can be.

When you are measuring in inches to four decimal paces you have to be picky about everything.

[bogiestl]

Getting a Fuerda ES series from Tools 4 Cheap... The guy who's running the outfit seems pretty cool, and answers stupid questions.

Tools4cheap LLC Online Machine Shop Tooling Store Fuerda Lathe Chucks

Either $312 for three jaw or $442 for six jaw, plus about $150 for the back plate. Not a "high dollar" but should be workable for my garage shop, and if I am lucky enough to wear it out, then I'll buy a Buck...

All the measurements are cumulative, and it seems like most normal three jaw chucks get about 0.003" ish... This should get me down under a thou. May end up getting one of the smaller ones for a fourth axis setup, but that's next year.

[neilw20]

Getting the chuck centered on the table can take quite a bit of time.
Any runout, as long as radial can be setup up really well.
Vertical wobble? You have a problem.
Once the chuck is true (on the OD) then true up and lap the jaws. New learning curve there. OD is important so the scroll is centered.
Grind the jaws true in place with (jig rings to preload), then lap with a soft steel bar and grinding paste.
I can put something in my 3 jaw chuck, and it clocks below 0.001" once the scroll is centered by lightly tightening at each chuck hole.

I am getting on in years and have picked up a few shortcuts along the way.

[Nelson_2008]

By "vertical wobble" do you mean, for example, a high or low spot when measuring the height of the table's surface with a dial indicator, as the table is rotated?

[neilw20]

By "vertical wobble" do you mean, for example, a high or low spot when measuring the height of the table's surface with a dial indicator, as the table is rotated?

YES

[wizard]

By "vertical wobble" do you mean, for example, a high or low spot when measuring the height of the table's surface with a dial indicator, as the table is rotated?

I suspect that is what he meant. In any event if you put a stylus on a taper, that rotates, you have to realize that you may pick up both axial and radial runout. This can impact your readings thus testing is often done with test arbors to isolate one component from another.

Morse tapers are relatively shallow so axial run out might not be a huge component in your measurements. However with a bit of time in front of a calculator you should be able to figure out how much each thou of axial runout impacts your readings.

I think it was you that asked in another post where to get morse taper arbors. One quick and dirty approach is to buy a Morse to jacobs taper arbor and turn the Jacobs to a cylinder. Or put a sleeve over the jacobs taper. Another approach is to use Morse taper arbors used to mount tooling. I often find these at auctions or Cabin Fever. There are a lot of oddly shaped arbors out there, some you can use as is others need a bit of machining. Another thing that pops up at Cabin Fever are odd sized or special purpose drill bits, these can often be cut in such a way as to expose useful shafting. Search a bit and you can find shops that make Morse test arbors and other goodies.

[Nelson_2008]

What about an MT2 collet, with something (e.g. a 0.5" reamer blank), chucked into it?