U drills

[fizzy]

Is anyone on here using them?
I missed a great offer from Cutwell sadly.
Found some cheap ones on AliExpress.
What are they like to use? In particular for boring large holes say 40mm on a lathe?
I bet @Kram will find some bargains

SP Series Drill Bites Insert Drill Metal Drill Bits 13mm-50mm Depth 2D 3D 4D 5D Indexable U Drill Machinery Lathes CNC Water - AliExpress 1420

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

 

[Erie Fred]

Is anyone on here using them?
I missed a great offer from Cutwell sadly.
Found some cheap ones on AliExpress.
What are they like to use? In particular for boring large holes say 40mm on a lathe?
I bet @Kram will find some bargains

SP Series Drill Bites Insert Drill Metal Drill Bits 13mm-50mm Depth 2D 3D 4D 5D Indexable U Drill Machinery Lathes CNC Water - AliExpress 1420

Smarter Shopping, Better Living! Aliexpress.com

www.aliexpress.com

What lathe ? HP to the spindle ?

 

[Agroshield]

There are three shapes of insert shown in that listing: square, trigon and diamond.

It would be wise to check what any particular one requires, make sure it is an ISO size and scope out cost of replacements.

AIUI, once the initial hole is drilled, they can also be used as a boring bar to enlarge to an intermediate size.

 

[Johnnybravo]

I use them. Be careful as some of the drills are now obsolete as you can no longer get inserts for them. The square inserts in particular seem to have be superseded with a slightly different shape (with stepped up corners)that does away with a long cutting edge that tended to make a lot of noise and chatter .

The triangular type inserts have been around for years. They are the most power hungry with the slowest feed rates out of them all.

 

[fizzy]

What lathe ? HP to the spindle ?

I have several
Colchester Triumph 7.5hp
2 Holbrook H20s with 10hp - pretty rigid. Only 40" between centres but weigh around 11,000lbs each

 

[Smouser]

I bought a couple of cheap AliExpress ones a while ago and stuck them in a drawer.

I forgot about them, I think tomorrow will be a perfect time to test them out.

*Edit*
On second thought, I think I actually bought indexable end mills and not U drills.

 

[Brad93]

You need power to drive them.

Ran a 40mm Tungaloy through cast iron today. Probably 90 seconds to go 2" deep.

Thats on a lathe with 30 hp spindle

 

[Brad93]

It's one of these.

 

[Brad93]

Or something quite similar at least

 

[fizzy]

You need power to drive them.

Ran a 40mm Tungaloy through cast iron today. Probably 90 seconds to go 2" deep.

Thats on a lathe with 30 hp spindle

I don't need that kind of speed.
Did you drill it from scratch or enlarge an existing hole?

 

[Smouser]

It's one of these.

View attachment 472753

More expensive than my Elliott Omnispeed lathe

 

[Erie Fred]

I don't need that kind of speed.
Did you drill it from scratch or enlarge an existing hole?

Every insert drill I have seen says do not drill pilot hole.
Also, If you don't run it hard and fast, they will rub, with bad outcomes.

Carbide needs to take a chip, and they are not nearly as sharp as your standard HSS twist drill.
so you need a high feed rate to keep them cutting, you need HP to keep it spinning at the recommended
speed.

 

[PhillipM]

I used to max out a 40hp HAAS spindle with a 36mm U-drill - they seriously soak up the ponies!

 

[Brad93]

I don't need that kind of speed.
Did you drill it from scratch or enlarge an existing hole?

You can't tickle things with them.

0.003"/rev is the minimum feed rate.
100-250 rpm in cast iron.

It's carbide, you have to push the insert into the work to make a chip. It's not like a big HSS drill where you can feed slow and take your time.

You'll need a carriage mounted/toolpost mounted holder too, unless you've got a mammoth tailstock it will just chatter and hum because you'll need an morse adapter to take the tool, which increases stickout.

 

[Brad93]

I used to max out a 40hp HAAS spindle with a 36mm U-drill - they seriously soak up the ponies!

In steel i bet it does.
This is soft concast bar used for sleeves.

 

[fizzy]

You can't tickle things with them.

0.003"/rev is the minimum feed rate.
100-250 rpm in cast iron.

It's carbide, you have to push the insert into the work to make a chip. It's not like a big HSS drill where you can feed slow and take your time.

You'll need a carriage mounted/toolpost mounted holder too, unless you've got a mammoth tailstock it will just chatter and hum because you'll need an morse adapter to take the tool, which increases stickout.

The tailstocks on my Holbrooks are insane. They must weigh 300kg each. Have a handle to wind along the bed. Morse taper 4 but the barrel would easily take a 6 or more!

 

[Brad93]

The tailstocks on my Holbrooks are insane. They must weigh 300kg each. Have a handle to wind along the bed. Morse taper 4 but the barrel would easily take a 6 or more!

All i can say is good luck

 

[Erie Fred]

How to clear the chips ?
I understand it's iron, but you might want to rig up at least some compressed aid (regulated down somewhat)
to blow the chips out.

 

[Brad93]

How to clear the chips ?
I understand it's iron, but you might want to rig up at least some compressed aid (regulated down somewhat)
to blow the chips out.

They fly out at 30 mph

 

[Smouser]

The tailstocks on my Holbrooks are insane. They must weigh 300kg each. Have a handle to wind along the bed. Morse taper 4 but the barrel would easily take a 6 or more!

Photos of these beastly tailstocks!!!