Milling a slot, with light equipment

Simple query, but interested to hear opinions. I only have a modest sized bench lathe with vertical table available for light milling. It works fine within its capabilities.

I'm just nearing the end of building Harold Halls' basic tool grinding table (as described in his book), and have a couple of 6mm dia slots to do in 5mm thick steel.

Just wondered if it was a) worthwhile b) quicker c) less wearing on cutters to: Chain drill and saw out the bulk first (eg to around 5mm) then mill with me 6mm cutter, or just to go straight to milling starting with a

5.5 and finishing with a 6 (which is the way I did it for a similar slot in the main table)

These 2 slots are in fact only for sliding adjustment of the mounts so are not critical - accuracy wise.

Any useful thoughts greatly appreciated regards Mike

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I'd do it exactly as you describe doing it last time. Tool wear mainly occurs when you push the tool hard so you aren't going to hurt your milling cutters if you take it steady. Drilling and sawing and then still having to mill anyway strikes me as having a dog and still barking yourself.

Reply to
Dave Baker

Thanks Dave I think I have a bit of a mean streak (& not a lot of money) so I tend to err on the side of - milling cutters are (relatively) expensive, whereas drills, sawblades & my muscles come cheap(ish). But you are right, I think I'll just mill it many thanks Mike

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In article , MikeH_QB writes

I agree with Dave, sod the chain drilling. I suspect you are more likely to damage your cutter by trying to plough through a series of drilled holes, as it may (depending on how much you can saw out) be experiencing "breakthrough" conditions at each hole.

BTW, if you wish to cut a slot in one go, do be sure to use a slot drill rather than an end mill; they are designed for this. An end mill (unless very much bigger than 6mm) will almost always give a wobble at the end of the slot, as the forward tooth leaves the work. Your way (5.5mm then

6.0mm) should be fine with an end mill, just twice the work.


Reply to
David Littlewood

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