Dovetail cutter???

[Olle]

I didn't have any problems with the depth. I just indexed the end mill on top of the sight base, then I indexed the dovetail cutter on the bottom of the first cut. I hit it within 1/1000". Why are you using the spindle as a reference?

[sheepherder]

Originally Posted by Olle

Why are you using the spindle as a reference?

It's the part of the mill that moves up & down.

What do you use???

[Olle]

Originally Posted by sheepherder

It's the part of the mill that moves up & down.

What do you use???

Ah, I usually call that the "head", and the "spindle" is on the lathe. I thouht you were trying to make every cut with the centerline of the barrel as a direct reference. I assume that you have a dial and fine feed on the Z-axis, so why do the cuts end up wrong?

My procedure for this (as well as plunge cuts, grooves etc) is to move down until the end mill touches the work, zero the DRO and then start cutting. The fine feed on mine is like a Glock trigger, very gritty, uneven and can jump too far if you're not careful. The DRO helps a lot, as I can see the actual position without having to rely on the dial.

Working on these mini-machines can sure be aggravating, once you learn their shortcomings you have to come up with a lot of workarounds to get the accuracy you need. It would be nice to have those zero back lash ball screws, that should eliminate quite a bit of error.

[sheepherder]

Originally Posted by Olle

Ah, I usually call that the "head", and the "spindle" is on the lathe.

I should have said "quill".

Everything on this mill/lathe is crudely [Chinese] machined. One graduation of the 'quill' handwheel dial should be .040" according to the chart. But my dial indicator says .037".

But it's not the mill/quill I'm talking about. It's the dial calipers. The digital calipers is consistently .010" off in measurements under .100", compared to the mechanical calipers . Zeroing doesn't help. And I can't get consistent readings with the mechanical dial calipers. Starrett calipers.

Can't pin down the problem. The dial indicator method works pretty well for measuring the depth of cut, but trying to get a consistent measurement of say a front sight base is fairly unlikely.

[Olle]

Have you tried the Starrett with a standard, for example feeler gages? I have a Mitutoyo, and I try it with a known dimension now and then just to make sure that it's not out of whack. If it is, I'm sure that Starrett can recalibrate it for you.

I believe the small discrepancy in the dial setting could be due to the feed screw being metric. Seems like some older machines used metric feed screws, and for the US market they simply changed the dials to read the "closest standard equivalent". These are said to be a bit iffy sometimes, so if that's the case you may want to upgrade to true standard screws and dials.

[sheepherder]

Originally Posted by Olle

I believe the small discrepancy in the dial setting could be due to the feed screw being metric.

Or the threads being tight at one point and loose at another. Just another reason to buy American. Interestingly, the same 3in1 machine is sold by Harbor Freight, Grizzly, and Smithy with different nameplates and colors...

I have a short list of accessories I'd like to get for it from Grizzly; they import more accessories than the others...

Edit: Ha! Sears now sells the Grizzly 3in1 as well as Grizzly!!!

Here's the Harbor Freight [red] and Sears/Grizzly [green] 3in1 machines...