What are you machining?

[doubleboost]

@RaceDiagnostics I recommend trying some En19t

There is some chatter - turn sound down a bit One of the stringers tried to shoot up my nose!

They are nearly breaking
Try a higher spindle speed
I just mess about with feeds and speeds
Until i hit the sweet spot

 

[Hopefuldave]

Yep, it's hard to go too fast for carbide! Proper depth of cut as (usually) carbide inserts have a bit of a radius on the cutting edge and won't cut until you pass it - reduce the feed rate so you don't run out of motor power/torque.

If you want to try coolant, it needs to be a constant flood or (if you're working it hard enough) the thermal shock of intermittent coolant can shatter the insert, cutting oil's ok as it doesn't have the same rapid cooling effect.

Unless you have unusually sharp-edged inserts, you can't take fine shaving cuts with carbide (that edge radius again), so *no sneaking up on dimensions*! Doesn't work!
Take the last two cuts (semi- and finishing) about the same depth, example: 20 thou" off final size, semi-finishing take a 10 thou" cut, measure to see what it took - say it's now 11 thou" oversize so it took a thou" less than dialled on - take the finishing cut accordingly, dial on 12 and it'll come to size - the loads on the two last cuts are pretty much identical so the tool will behave the same.
This assumes you've got the gibs adjusted right, toolpost's locked down properly etc. etc...

Dave H. (the other one)

 

[ronan]

Yep, it's hard to go too fast for carbide! Proper depth of cut as (usually) carbide inserts have a bit of a radius on the cutting edge and won't cut until you pass it - reduce the feed rate so you don't run out of motor power/torque.

If you want to try coolant, it needs to be a constant flood or (if you're working it hard enough) the thermal shock of intermittent coolant can shatter the insert, cutting oil's ok as it doesn't have the same rapid cooling effect.

Unless you have unusually sharp-edged inserts, you can't take fine shaving cuts with carbide (that edge radius again), so *no sneaking up on dimensions*! Doesn't work!
Take the last two cuts (semi- and finishing) about the same depth, example: 20 thou" off final size, semi-finishing take a 10 thou" cut, measure to see what it took - say it's now 11 thou" oversize so it took a thou" less than dialled on - take the finishing cut accordingly, dial on 12 and it'll come to size - the loads on the two last cuts are pretty much identical so the tool will behave the same.
This assumes you've got the gibs adjusted right, toolpost's locked down properly etc. etc...

Dave H. (the other one)

Nay, get within 80 thou and spend an hour with 80 grit emery

 

[Hopefuldave]

Nay, get within 80 thou and spend an hour with 80 grit emery

May I offer sir the loan of a nail file?

Dave H. (the other one)

 

[Kram]

Sorta right on sneaking up. Does depend on the insert. I dont trust the calculated deep cut when a manual feeding, there can be a lot of spring that changes start and end of cut. When you need an exact size its worth swapping for the sharp ones.

100 x50mm mild steel. Will bore it out to 62mm 25mm long and shrink fit the en19t in.

I was going to reuse the rest, but the 57mm holesaw is painful to use, might give up and bore it out.

 

[Kram]

Old hard disc magnets are useful. I need a face shield!

 

[Kram]

Shrink fits are satisfying. A good way to burn fingers.

 

[Kram]

Er40 holder, used 40mm holesaw which is perfect. This time I gave plenty of space for the nut to stay on and a size label. Four more collets in the post and I'll chose a few from 3-20 for the other spaces

 

[Brad93]

Er40 holder, used 40mm holesaw which is perfect. This time I gave plenty of space for the nut to stay on and a size label. Four more collets in the post and I'll chose a few from 3-20 for the other spaces

bOTT do some great plastic holder/tray things.

 

[Pete.]

En19 stringer nearly cost me a finger . Two years on still have trouble with it

I neatly sliced off the face of my fingertip a couple of years back, and more recently sliced my nose open when pulling my 'workshop' polo shirt back over my head with a tiny curl of EN19 stuck in the collar.

 

[Kram]

Er40 turned out well so quick and dirty one for Er32.These used to be doors on a very old plywood cuboard.

 

[Kram]

Had to recut the er40 spindle register and took some time to clock in but got near as perfect.

 

[Kram]

Dont have a drill press, this will do. Milling setup needs a bit more work as the new screw is not well aligned.

Bolted up, almost ready to cut taper and thread, but since Ive got the milling setup Im going to try the new 50mm facemill...

Im happy with that finish. Excuse the fingerprint.. H01 insert. The general purpose inserts not good on aluminium.

 

[Kram]

50mm facemill with mild steel on a lathe? Not very good. It is still in the hard skin but half hour for 0.5mm...
It'll improve when I add support on the vertical.

These 18mm Hydra cutters no problem. 0.5mm cut and Im sure can do more.

 

[Hopefuldave]

50mm facemill with mild steel on a lathe? Not very good. It is still in the hard skin but half hour for 0.5mm...
It'll improve when I add support on the vertical.

These 18mm Hydra cutters no problem. 0.5mm cut and Im sure can do more.

Until you add support on the vertical... Bring the tailstock up and lock it against the back of the milling slide for the cut, helps add a bit of rigidity and you'll get a more consistent milling cut with a better finish - I used to do that (had topslide on a big angle plate bolted to the cross-slide tee slots) before I got my milling machine, it made milling on the lathe a bit less unpleasant!

Dave H. (the other one)

 

[Kram]

Wanted to try making an axa holder. Milling a slot would be painfully slow, but I had an idea of drilling out most of the material. It still took bloody ages milling might have been quicker.

 

[Kram]

Ive changed to a new 12mm chinese endmill, as I have no spare travel to drop work down. I am very suprised - its an open slot but it was quite happy 2mm deep cut, full width and moving fast, even happy 1mm deep climb milling. Im sure it will be worse with vertical raised higher.

I need a vice with a smaller bottom jaw, 30mm seems OTT, im sure 15mm would be adequate!? Ill get some csk bolts then I can drop another 10mm.

 

[Dcal]

Today I machined another tipping wheel for the bead roller.

I have an earlier version that I welded and then machined (because I didn't have a big enough lump of bar) and that works fine.
This is for a mate but I might make one for myself as well.

It's made from a bit of tie-bar that came out of a harbour wall we were demolishing, I'm sure 20 years ago.



It was too big to fit in my 3 jaw and I should have put it in the little 4 jaw but instead I tack welded a bit of bar to it and mounted it in the chuck that way.



When I machined the first side down I was able to turn it and mount it in the chuck then use a parting tool to cut the bar off.



It didn't like it and broke the parting tool tip.
The heat affected zone was a hard as the hobs so there must be a bit of carbon in the bar.
This is good (I think) as I might have a go at hardening the whole thing.
The bar had hardened to a fair depth and was still hard 3mm in.

The rest went fine and I did clock it in the 4 jaw to finish off the other side.



Very simple thing but I'm quite pleased with it as it's about the level my machining skills have reached.






Has anyone any idea what grade steel a 70 year old 3 inch tie-bar would be made from?

 

[fizzy]

Today I machined another tipping wheel for the bead roller.

I have an earlier version that I welded and then machined (because I didn't have a big enough lump of bar) and that works fine.
This is for a mate but I might make one for myself as well.

It's made from a bit of tie-bar that came out of a harbour wall we were demolishing, I'm sure 20 years ago.

View attachment 216597

It was too big to fit in my 3 jaw and I should have put it in the little 4 jaw but instead I tack welded a bit of bar to it and mounted it in the chuck that way.

View attachment 216592

When I machined the first side down I was able to turn it and mount it in the chuck then use a parting tool to cut the bar off.

View attachment 216593

It didn't like it and broke the parting tool tip.
The heat affected zone was a hard as the hobs so there must be a bit of carbon in the bar.
This is good (I think) as I might have a go at hardening the whole thing.
The bar had hardened to a fair depth and was still hard 3mm in.

The rest went fine and I did clock it in the 4 jaw to finish off the other side.

View attachment 216594

Very simple thing but I'm quite pleased with it as it's about the level my machining skills have reached.

View attachment 216595

View attachment 216596


Has anyone any idea what grade steel a 70 year old 3 inch tie-bar would be made from?

Wrought iron!

 

[Kram]

Taper almost done

Will it do any harm to bore out to 32mm? As Ive got a 32mm collet, the taper small dia. is normally 31mm.