Thread: Drilling and Milling on the Lathe

Nice work as usual

I always look with envy at the accuracy and finish you get on your work. Makes my stuff look really clunky. Keep posting though - I'm on a big metal work learning curve at the moment and seeing your stuff makes me want to keep at it.

Andre, Bob. It's all trick photography. I don't show you the #### ups! Yesterday I was turning the boss down from 50 to 12.7mm. Being lazy, I came unstuck when I tried to peel 10mm off the diameter in one pass with powerfeed. It would have worked if I had engaged the live centre. With no support the cutter jammed and twisted the boss in the chuck, stalled the 1 horse motor but because I was lucky I didn't destroy my carbide insert. Lucky because 1214 is as tough as chewing gum.

I also had a hell of a time trying to set up the inch bar in the 4 jaw chuck and adjust it so that the bar was running true at the outboard end 300 mm away. I had to reduce the ends to 16mm. If I wasn't lazy the lathe would be level and wouldn't turn a taper. The bar I used was 1 inch 1214. I reckon it was oval not round. I tried my hand at turning between centres yesterday for the first time. I need more dogs. I also need to know how you are meant to centre drill the ends of a long bar larger than the lathe spindle bore.

I've got a long way to go.

BT

Originally Posted by Anorak Bob

I tried my hand at turning between centres yesterday for the first time. I need more dogs. I also need to know how you are meant to centre drill the ends of a long bar larger than the lathe spindle bore.

I've got a long way to go.

BT

Easy done Bob. Use your fixed steady for support.

Phil

Hi Bob,
I don't care what you say, that looks pretty good.

One thing that is mentioned in Harold Halls book is working on the end of a bar too big for the lathes bore. He suggests zeroing the piece in the chuck, setting the fixed steady at the chuck and then moving the steady to the end of the job. I can't try this as my steady won't get close enough to the chuck, due to the gap bed in my lathe, and of course the job would have to be parallel already. You can also set the bar in a cup center to set the steady.

Ewan

Edit: i see Phil beat me to it, i'm a bit slow tonight after a big few days.....bed time i think

Not slow Ewan just very thorough.

Phil

I hate centering long stuff in the 4 jaw I had to center a piece of 120 mm bar 500 mm long at work the other day pain in the backside

looks great bob. is that a hercus 9" your using? i haven't tried a 5mm doc on my 9" maybe on aluminum Ive done it but not steel.
as for a center drilling long bar if i had to do it id mark out the bar. ie find center of the bar. center pop it and use a fixed steady on the lathe to support the shaft while center drilling or a drill press .
how come u couldn't just set you work up in a four jaw to bore the hole.
makes me feel like some shed work.
aaron

Originally Posted by Anorak Bob

I also need to know how you are meant to centre drill the ends of a long bar larger than the lathe spindle bore.

Bob, in principle you use a fixed steady to hold the far end still and concentric - then centre drill.

If the part is too long, you may be able to mark the centre with a centre finder and then centre drill it off the lathe - e.g. on a pedestal drill, then mount it on the lathe for turning operations.

Joe

Hey Boys,

I might take risks but I ain't completely crazy! I was using my fixed steady.

Originally Posted by jhovel

Bob, in principle you use a fixed steady to hold the far end still and concentric - then centre drill.


Joe

Exactly what I did yesterday Joe. Because the bar was out of whack, the chuck end was wobbling about while the outboard end ran true.

Bob.

Apologies Bob. I thought you were asking about centre drilling. I'll crawl back into my hole now.

Phil

Originally Posted by azzrock

looks great bob. is that a hercus 9" your using? i haven't tried a 5mm doc on my 9" maybe on aluminum Ive done it but not steel.
as for a center drilling long bar if i had to do it id mark out the bar. ie find center of the bar. center pop it and use a fixed steady on the lathe to support the shaft while center drilling or a drill press .
how come u couldn't just set you work up in a four jaw to bore the hole.
makes me feel like some shed work.
aaron

Yes Aaron, my '69 ARL. I like it.

Originally Posted by Steamwhisperer

Apologies Bob. I thought you were asking about centre drilling. I'll crawl back into my hole now.

Phil

Come back out Phil. Please. I was asking that question. Lets say you've got a length of unpeeled black scaly nasty 4140. I guess that's where the centre finder comes into play along with the centre punch. You couldn't use a steady because of the ragged nature of the bar. Between centres would be the way to go. Having a level machine is a prerequisite.

BT