Rotary Table

[Bill Shields]

I disassembled mine because I could not get it into the lathe in one big lump.

[John Hasler]

Why would you put it on the lathe? I'd do it in place on the table with an endmill. Can't get any more concentric than that.

[Bill Shields]

Personal preference

I do not like trying to make round holes with endmills

[whateg0]

Personal preference

I do not like trying to make round holes with endmills

That's what the rotary table does though. I guess to each his own

[Bill Shields]

Considering the depth and diameter involved for my table, I prefer to single point in a lathe.

[Harold_V]

Personal preference

I do not like trying to make round holes with endmills

Chuckle!
Sounds like you're coming down with mental health, Bill!

While one *might* enjoy success in achieving roundness, the chance that the hole will be straight when generated with an end mill is not good. That's particularly true if the length of cut is extreme, and exacerbated if the end mill in question is made of HSS instead of carbide.

H

[Russ Hanscom]

Since the hole is likely to be a bit larger than the end mill, only side cutting will be involved, which should be a common endmill exercise.

I think I would accept the procedure.

[Bill Shields]

I agree if the L/D were conducive to such.

To get through my table is a hole .625 diameter (started out as metric something) by some 2.5" deep.

I just was not comfortable doing it with an end mill esp since it is cast iron and I ended up single point boring with a carbide bar to get it straight top 2 bottom.

In hindsight I could have pushed a drill thru it then clean bored just the top 1/2 inch or so...but at the time sticking it in the lathe seemed the solution.

[Harold_V]

Since the hole is likely to be a bit larger than the end mill, only side cutting will be involved, which should be a common endmill exercise.

I think I would accept the procedure.

Bad choice if size, roundness and straightness is important, and made worse if the cut is long, although for a short bushing you might get lucky. They grind these things for a good reason.

End mills, especially HSS end mills, rarely cut what you'd call straight, and even a tenth of deflection would result in two tenths taper (on the diameter). If the resulting hole wasn't dead straight, it may not serve the intended purpose properly, but then even that is open to debate.

I can't help but think that in this case a great deal depends on the nature of work one might expect, and the results you could achieve. For some folks, "close enough" is good enough. Not a good strategy in the long haul, though, as you never know when you'll be called upon to deliver a level of quality that is beyond the capability of the tool in question.

Note that I did not say an end mill wouldn't work. Sure it will, but then you can also paint your car with a broom. Doesn't mean it's a good idea.

H

[AllenH59]

I have a grizzly 8" rotary, it also has a morse taper, I have a chuck on mine. very occasionally I use it without the chuck..

[liveaboard]

I plan to make a chuck adaptor so I can use the 4 chucks I have for the lathe on my rotary table too.

The Rotary table has a really small center hole, which is a bit unfortunate and will no doubt be the limiting factor for some work; so I was puzzling about how to make the chuck arbor center reliably, without fitting inside the hole and constricting it further.

So after reading this thread, my plan is to use an end mill to cut a small spigot notch around the center hole, just a few mm deep and wide, for a collar to fit into.

Even when reading why something is a bad idea, it can lead to a (hopefully) good idea.

Just as soon as I solve the electrical problems and get the mill to work...

[Harold_V]

A shallow, small depth of cut (they're not the same thing) with an end mill can yield a functioning hole, of that there is no doubt. The shallow depth should limit end mill deflection, as should the small depth of cut. Make your final pass just a thou or two and there should be no deflection---the only error will be that which is ground in to the end mill, if any. Modern carbide end mills should be pretty much dead straight.

Even if there is minor deflection, it is most likely that you will be at the mercy of the degree of precision of the bearings in the rotab-----but that's no different from the results you'd achieve when using it, with or without the new cut.

The center hole of a rotab, when used with the hole vertical, serves no purpose aside from providing centering. The size isn't important so long as it serves your needs, and you can tool up accordingly. It need NOT be large, as you can't really clamp anything through the hole. If you did, the table couldn't rotate unless it was used with the bore horizontal---so if the hole you have is large enough to accommodate the size of clamping devices you have, you should be good to go.

H