Sorting out accuracy on my Mill/Lathe

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djh82uk:
Well Ive been working on both machines today, I did not have the confidence to start adjusting the taig, I have 3 thou backlash on the Y, 2 thou on the X and 1/2 a thou on the Z, I did clean everyything completley stripping down the X & Y and relubed, adjusted gibs etc. Still need to clean & lube the Z.

As for the lathe, I was looking on mini-lathe.org.uk and read about how his chuck was out by 15 thou, and when he got it to 2 thou he was very happy, so I guess i should be reasonably ok with 1 thou runout for now.

As for the saddle, I took the splashback off and got to work, there does not seem to be any brass gibs, just 2 cap screws, 2 lock screws (grub screws & nuts) and a brittle piece of steel.

Sooo, one of the cap screws was so loose it could be turned by hand, so I set about getting them to the same tightness, and then started tightening the locking screws, the saddle now is a bit tighter to turn, and probably would tire my arm out if I had to move it three lengths one after another, but....

After puting the dti on the bed and the arm on the carriage, I can try and lift the saddle and the dti deflects by about 1/4 of an increment which is roughy 0.0025mm, which I expect is ok for now, also adjusted the backlash screws for the cross-slide and and got that nice and smooth with minimal backlash, the compound was ok from last time I adjusted.

I also took the time to completley clean and lube everything.

I tried a test cut, pic below, not perfect but better, the dis-coloration is my oily fingerprint btw

DJH

djh82uk:
Still not 100% happy with the finish, or is this about what I can expect? I can just about see lines in the workpiece, but can just about feel them if I run my nail along it, Should the workpiece always need finishing afterwards? Im not sure if it is the lathe or the tooling, I have carbide with (changeable tips) & TCT brazed, both give a similar finish, or should I be using HSS? (I have never properly tried grinding my own tools but need to learn, should I be using a slightly rounding tip for finishing?

My next few tasks are to tram my Mill (desperatley needs doing, but never done it before), not sure how to be able to check how far out it is.

Center my tailstock & to check runout on my mill spindle

NickG:
DJH,

that looks a really good finish on the pic to me. it doesn't really matter about run out on the chuck body it's on piece of metal gripped in the jaws that counts. 0.001" is good for a s/c chuck I would say.

nick

djh82uk:
Hiya

I don't use a S/C chuck as the only 4" chuck I have is independant, it's ok tho.

I think i need to look into tooling, could someome post up a pic of the tool they use for a nice finish on aluminium?

Im not sure a carbide tip is the way to go?

Should I have a slightly rounded tip?

I also tried cutting mild steel but got a bad finish with carbide, I need to figure out tooling next i think, I just use whatever i have at the time which is obviously not the way to go.

I guess I also need to learn to grind my own

DJH

Darren:
I've never had any trouble using carbide on aluminium, brazed, tips coated or otherwise.

But I know people swear by HSS.

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