Toolpost Grinder Vs. Spin Fixture

[Andre]

Lately I've been turning a lot of metric diameters and bores on the lathe, for bearing journals. For multiple reasons I'd like to make a small 1 - 10mm pin/plug gauge set in 0.5mm increments. A 20 piece set out of O-1 tool steel.

My question is after hardening should I grind them on the lathe with a toolpost grinder or use a precision fixture on the surface grinder to grind them? I would like to hit .0002" on the diameter and .0001" roundness to hit "ZZ" specification, although overkill for my needs.

 

[rrjohnso2000]

That is a job for the surface grinder.

 

[Tony Wells]

With those as choices, I'd go with the lathe and tpg, as long as the bearings in the headstock were good and tailstock uses a dead center.

 

[JimDawson]

I would try it on both machines and see which works best. That's tight tolerance, so is also going to require a little experimenting to get the technique down.

 

[stupoty]

Are you going to leave a large shaft at one end? I'm imagining trying to locate 1mm part in a 4 jaw

Stuart

 

[Wreck™Wreck]

Good Luck

 

[Holescreek]

I'd just order the pin gauges from Mcmaster carr for <$3 each, maybe less for a set.

 

[ARKnack]

I agree with holescreek, pin Gage's aren't expensive. Here are their class tolerances.

TOLERANCE OF GAGES

The difference between a Class Z gage and Class ZZ gage is the deviation allowed in the manufacturing process for tolerance and geometry and does not define the useful life of the gage. Helpful reference materials are as follows, below is a sample from B89.1.5-1998 ANSI / ASME Standards:

Class ZZ has an allowed deviation of .0002″, geometry of .0001″, finish 10 micro-inch Ra

Class Z has an allowed deviation of .0001″, geometry of .00005″, finish 8 micro-inch Ra

Class X has an allowed deviation of .00004″, geometry of .00002″, finish 4 micro-inch Ra

Class XX has an allowed deviation of .00002″, geometry of .00001″, finish 2 micro-inch Ra

 

[cvairwerks]

A set of pins from .22mm to 12.70mm from Meyer, in Z class, contains 625 pins and runs about 900 bucks. Choose your diameters by .5mm and buy the individual pins and you around 80 bucks or so.

 

[rgray]

I would use the surface grinder and a small between dead centers fixture. Whirly jig / spin fixture is great to but the setup time would be longer.
My between centers fixture has the end piece held on with a socket head cap screw, works great with a cordless drill spinning it so as not to be so tedious.