Mounting drills

[m_c]

I've got a Conect 121 (basically a CNC'd Myford ML10), and I'm struggling to come up with an economical way to mount several drills, so it's just a case of switching the drill/holder, and setting Mach on it's merry way again.

I've got a model 200 (down the page at Tool Posts - Arc Euro Trade) quick change toolpost fitted, and was thinking boring bar holders with ER chucks, but given the initial items I want to make involve 2 drills and a reamer, that would be 3 holders at £30 each, plus making ER collet holders.
Only reason for the ER collet holders is for easy adaptability for future use.

I had thought about gang tooling, but there just isn't enough Z-axis travel.


Are there any other options I could consider, which don't involve a tool changer?

[TXFred]

I had to search for an image of that lathe to understand that you're up against.
That thing is tiny.

http://farm2.static.flickr.com/1418/...ea0fd159f5.jpg

What you need is a way to gang the drills, and have them all be about the same length. That's fairly easy if you use screw machine drills. They're nice and short. Get good quality drill bits that have a modified split point. Then they'll be self centering, and you can eliminate the need for a center drill.

But then you have the problem of the reamer. The solution may be to just cut the reamer down to length.

If you can gang them, I highly recommend it. Changing tool holders every 20 seconds will get really old, really fast.

Frederic

[m_c]

Nice photo you found!
Newer/cleaner version can be found at It lives! | Flickr - Photo Sharing!

You're right that changing tool holder every 20sec isn't good, but it'll still get things done quicker than the current manual lathe.

I'll need to go and measure up again, to see if there is some way to get enough room to gang the drills, while still being able to get a right hand turning tool in.

Just had an idea. If I can move the QCTP furtheraway from the centreline, I could use a left hand facing tool mounted in parellel with the drills, which might give me enough room...

[TXFred]

Nice photo you found!
I'll need to go and measure up again, to see if there is some way to get enough room to gang the drills, while still being able to get a right hand turning tool in.

We're talking about two different things, I see now.

What I meant was that you could create a single toolholder for your existing QCTP, and that toolholder could hold two drills and a reamer in a gang. Then you could remove that and mount your turning toolholders.

This lets you keep the flexibility of the QCTP but still have some of the speed of gang tooling.

Here's an example of one for larger machines.
Dorian Tool Introduces Victory CNC Quick Change Gang Tool

Frederic

[mfgbydesign]

I couldn't look at your photos; blocked by corporate firewall.
Just for brainstorming purposes, I designed a double drill holder using hardinge collets so I could tool a lathe to produce 79 different part numbers without changing tools out. I realize you don't have a turret as I did, but you might get some ideas for gang tooling. I bored the collet holes by mounting a boring bar in the chuck. On the Okuma I had seperate offsets for each tool. T0101 might be one bit and T0121 might be the other bit in the same holder (been awhile).
http://www.mfgbydesign.com/images/lathe_2tool.jpg

[m_c]

frederic, I understand now!

I had seen that set-up somewhere before and had totally forgotten about it, but it looks like it could be a good solution for now. Time to go and do some looking and head scratching, to see what I can come up with.
Thanks for the suggestion, and link!


mfgbydesign, that's some setup!
I'm not planning on anything that needs quite that many tools just yet...

[m_c]

After much sketching, thinking and some more sketching, I came up with a plan.
Then realised said plan wouldn't work, so done a bit thinking, and some more measuring, and a bit more thinking, and am now partway through making a tool holder.

So far I've got the main lump of metal machined to fit in a standard QC tool holder, and have the stabiliser foot machined. I now need to make a couple T-nuts to secure the stabiliser, and then bore some holes to accept some ER20 collet holders.
Here's a couple pics so you get the idea.

Gang tool holder by mc_mtb, on Flickr


Gang tool holder by mc_mtb, on Flickr

[A1CNC]

You might take a look at how Omni turn does it. They have gang tool lathes that are highly regarded.
OmniTurn NSK Live tools Pages

look around their site, you might find some ideas.

[sansbury]

Another idea, to keep things on the cheap, would be to make your own drill holders from .500" drill rod. You take a section about .750" long or so, and drill a half inch into that with the drill you want to hold, and use your choice of a set screw, loctite, or silver solder to hold it all together. Machine a flat on the drill rod and bore some .500" holes in your slide, and you've got a poor man's interchangeable tool system. ER20 is great of course, but a little spendier and harder to DIY.