Thread: Boring a 55mm hole in 5 cuts

hi nice one what speed are you boring that at?
does your lathe have a dro? how did you tell it was
right size bore?
aaron

Originally Posted by andrew_mx83

Hi guys, been too snowed under with work to post on the forums recently but i thought id contibute a quick video of some holes i am boring tonight

https://www.youtube.com/watch?v=XVgz...e_gdata_player

1) drill to 10mm
2) drill to 32mm
3) bore to 42.5mm
4) bore to 50.5mm
5) finishing cut at 55mm

2.5 minutes, now thats how you bore a hole

that was a big cut you took with that boring bar . what lathe is it ?
Peter

10mm drill and boring cuts @ 1400rpm
32mm drill @ 160rpm

I have poor mans DRO (digital scales) but rarely use it on the cross-slide, i just count handwheel revolutions and cut at the same graduation each time. This gets me repeatability of 0.02mm which is more than accurate enough for these parts.

Peter it's a Hafco AL960B and i am using cermet inserts (as always). 5mm DOC with generous feedrates are not uncommon....

They are a great lathe, i absolutely love it.

Originally Posted by andrew_mx83

2.5 minutes, now thats how you bore a hole

2.5 minutes, now you could have bored a whole forum with that....but i like it!

Bad pun, i know, sorry its late and i need to go to bed......

Why not use the feed till the finishing cut, so the chips would break up?

Cheers,
Ew

I only ever use power feed on finishing cuts, i like the feedback you get from using the handles. its easier to abort that way if things start to go pear shaped on big roughing cuts.
Id love to CNC this thing but then i couldnt get away with 'turning by ear' so much.

Sure is bed time, ive made enough swarf and put enough holes in my hands for today... tomorrow those parts all go on the mill for drilling and slotting, then tapping, then assembly... gonna be another late one )

Dear Santa. A Hafco AL960B this year please, I have been good.

Originally Posted by andrew_mx83

Peter it's a Hafco AL960B and i am using cermet inserts (as always). 5mm DOC with generous feedrates are not uncommon....

They are a great lathe, i absolutely love it.

great.
I have same lathe that I brought not long ago and is in progess of setting it up . danm my floor is about 30mm off in the tail stock side so i need to weld some 16mm plate under the two cabs and jack it up for balancing.
any tips on this ?
cheers
Peter

Good quality video.

What camera did you use ?

Now if that was steel it would be really interesting

Rob

dont you have 55mm drill?

Originally Posted by thorens

great.
I have same lathe that I brought not long ago and is in progess of setting it up . danm my floor is about 30mm off in the tail stock side so i need to weld some 16mm plate under the two cabs and jack it up for balancing.
any tips on this ?
cheers
Peter

Ha, my floor isnt flat, or even concrete! The lathe sits on a sheet of 19mm chipboard which was roughly levelled by hand. Now im only 5'9, but i found the lathe way too low and was killing me to bend over all day so it now sits on 100mm riser blocks which are really just a length of 200x100RHS under each cabinet.
My only tip would be to look at the ergonomics and your posture while turning, i think you will find 16mm is not enough. If you need to level it as well maybe some adjustable feet are in order.

Originally Posted by nearnexus

Good quality video.

What camera did you use ?

Now if that was steel it would be really interesting

Rob

The video was just taken on my Asus tablet. I realised that i have a handy spot where it can sit and record turning work quite easily.
I can cut deep in steel, but not that deep. I was boring steel @ 34mm last week -10mm drill, 11/16 drill, 1" drill, 32mm drill, 1 cut on the boring bar.
I will try and video some cermet cutting of steel one day, it is rather impressive (swarf comes off blue)

Originally Posted by azzrock

dont you have 55mm drill?

Not yet! But maybe i should make one? Indexable of course. I have an insert there to make a 25mm drill but i could use multiple turning inserts to get out to 55mm if necessary.