Furrows on a milled edge

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... and when despite this you still get tiny brass splinters stuck in your skin, an illuminated magnifier helps, and your Vernier or digital caliper excellently fulfils a secondary purpose of pulling the bu99ers out...

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Emco dropped the ball when they designed the milling attachment for the Unimat 3. It uses sleeve bearings, which can't be adjusted. The spindle end-float also can't be adjusted properly. The pulley is pressed onto the spindle - its position determines the end-float. It can be 'adjusted' by judicious use of press or more brutal techniques.

I have two milling attachments (don't ask...), both bought barely-used, but both have unacceptable play in the sleeve bearings, making the attachment effectively useless for milling. I would imagine that they have been like that since new and have not worn excessively. The result is as you have shown. I suggest you check your spindle for radial play.

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Barrie, your result looks pretty good, vastly better than what my machines will do. Yes, prev. post was directed to OP, but also as a warning to all owners.

Yes, I did mean radial play - as a result of slack sleeve bearings / bushes. Particularly annoying, because correction requires replacement, possibly custom manufacture, unless modification is considered. One forum member was intending to fit anti-friction bearings, and it's been written up in ME - ages ago. Unfortunately, it seems to require the manufacture of a smaller diameter spindle, so rigidity may be compromised. Perhaps fancy bronze/PTFE, or other 'plastic'-containing bushes are the simpler answer. One day, I'll sort mine out...

Of course, the silly pressed-on pulley design means that elimination of axial play is difficult to eliminate, but at least one can try to adjust it out...

Barrie, just in case you were wondering, the milling spindle is removed by pressing it out, (nose first) through the pulley. Do let us all know how your project goes.

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Depends what you define as useless, I made use of mine to do all the milling on this.

Surprised that nobody has picked up on that yet, or did I miss it? Using a drill chuck is a definite no. They are not designed to take the sideways force. You need to use a collet chuck or, failing that, a three jaw as Jason did.

Russell

Note that you said that you used the Drill Chuck for milling.

DON'T.!

Drill chucks are designed for axial loads, not side loads.

So part of your problem is probably caused by the chuck flexing. You could even have a cutter come out of the chuck.

Use a proper Collet Chuck, or 3 jaw, which will withstand side loads. Also make sure that the arbor is tight in the quill.

For climb milling, nip the table clamps, to withstand the cutting forces which will try to drag the work into the cutter. hence to advice about only taking very light cuts..

Should have typed this earlier!

Howard

The quill is solid so you can't put an arbor up it. Or as I mentioned the shank of a long cutter.

The pulley screws onto mine. If you take it off and slip a suitably sized bit of tube over the end of the shaft and then put the lot in a press or even a vice you can push the metal collar down further to take out any end float.

It would probably be possible to take it all apart and put say a 1mm pitch thread on the spindle and fit a couple of lock rings, this combined with a slightly looser collar would make it more easily adjusted.

I became so disappointed with the poor milling head design of the Uni3 that I decided to use a Uni sl headstock instead. It is mounted on a spare rod of 24mm steel, drilled to fit the Uni3 (to keep the sl bar original) I can now mill steel with relative ease.

Dave.

Nurse should have tucked me safely up in bed, instead of letting me play on the computer after my bed-time. Of course, JasonB is right, the pulley screws on and it's a collar that's pressed onto the spindle shaft. I was working from memory (dangerous these days) - the vertical heads have been stored away and forgotten about, for some time. Sorry for any puzzlement caused.

The anti-friction bearing mod was the subject of this thread. I'm horrified to see that four and a half years have passed since then, and I've achieved nothing useful in that time...

Edited By Kiwi Bloke on 07/08/2019 07:02:54

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