[keen]

Drilling long holes through tough steel has always been a pain - But my Tormach make it so much easier. For this work G83 is a Godsend.

I use a simple split bush to hold a 8.0mm long series drill direct in the R8 to gain max room.

Feel free to post any info you have on deep hole drilling - cheers.

[zephyr9900]

Very nice, Keen. Are there guidelines for when to use G83 vs. G81? I always use G83 (full retract) whenever a hole is more than about 2 diameters deep in all metals but don't know if that is really necessary.

Randy

[300sniper]

i get some great ideas every time i click on this forum. i wish i saw that a few weeks ago. i was trying to drill a large diameter part on the 4th axis and didn't have a stub length drill in the size i needed. i could have saved a bunch of length by ditching the chuck and using your bushing idea.

thanks for posting.

[philbur]

Am I missing something here. Why not just use an 8mm R8 collet. Assuming you have one, which if you don't then shame on you.

Phil

PS: It's a bit dodgy gripping a drill bit on anything othet than the plain shank.

i get some great ideas every time i click on this forum. i wish i saw that a few weeks ago. i was trying to drill a large diameter part on the 4th axis and didn't have a stub length drill in the size i needed. i could have saved a bunch of length by ditching the chuck and using your bushing idea.

thanks for posting.

[zephyr9900]

It's a bit dodgy gripping a drill bit on anything othet than the plain shank.

Phil, keen is gripping the drill bit on the plain shank. You can see that the flutes stop well below the split bushing. But also a split bushing withstands the torque of the axis stepper motors, so keen's application seems safe to me.

And I'm not keen (much to his relief, I'm sure!) but I own two R8 collets. I grumbled about buying the 5/8", but needed it to hold a dovetail cutter that I couldn't find in a 3/4" shank to hold in the Tormach's standard collet.

Randy

[philbur]

I wasn't referring to Keen. I guess I missunderstood you intention regarding the need for a stub drill.

Phil

Phil, keen is gripping the drill bit on the plain shank. You can see that the flutes stop well below the split bushing. But also a split bushing withstands the torque of the axis stepper motors, so keen's application seems safe to me.

And I'm not keen (much to his relief, I'm sure!) but I own two R8 collets. I grumbled about buying the 5/8", but needed it to hold a dovetail cutter that I couldn't find in a 3/4" shank to hold in the Tormach's standard collet.

Randy

[zephyr9900]

I understand, Phil. But my point was that with a Tormach, there is hardly ever a need for anything but the single R8 collet that comes with the machine. Mark me down on the list of people who thinks keen's split bushing for a one-time use was very clever.

Randy

[300sniper]

I understand, Phil. But my point was that with a Tormach, there is hardly ever a need for anything but the single R8 collet that comes with the machine. Mark me down on the list of people who thinks keen's split bushing for a one-time use was very clever.

Randy

i am like you randy. i only have my 3/4" r8 collet. i keep saying i will buy a set but haven't gotten around to it.

i like keen's idea because when in a situation like when i needed to drill something NOW and i didn't have enough room in the z, i could run over to the lathe and make a split bushing in just a few minutes. that is much faster than running home, getting online and ordering either the correct collet or stub drill and then waiting for it to arrive.

i am also thinking even if i ordered a set of r8 collets, i'm not going to have one for every drill size, letter, number and fraction.

[keen]

hi Phil - The split bush is 3/4" and works as as a TTS quick change (height set offline and set for level flush with the bottom of bush for measurement and installation - good enough for drilling depth) - also I only have a couple of R8 collets - not that size.

Hi Randy - yes I use G83 from about 2 diameters down also. Best to be conservative so the machine can run unattended. I use a short peck also - 2mm keeps the swarf short and avoids untangling attention.

Cheers.

[philbur]

Can't believe you guys have got a $7,500 + machine and don't have a set of either R8 collets or an ER collet chuck (TTS even) and a full collet set, or both.(chair)

Phil

[justgary]

Phil -

I don't remember them saying they didn't have ER collet holders. The TTS ER holder is pretty long, so it wouldn't work for holding an extended drill anyway.

I'm with them; I own exactly one R8 collet. I never got around to buying a set, and so far I haven't missed it either. On the other hand, I don't have enough ER holders, and would like to get more.

Keen -

Thanks for posting the idea. I'll keep it in my back pocket.

Regards,

- Just Gary

[keen]

Cheers - Ive got 3 TTS ER holders - and a bundle of collets. Enough for most jobs - usually only 2 or 3 tool changes per set up.

Yes the ER TTS was too long to hold the drill - I had the spindle almost touching the top of the job.