[thorengebretsen]

Hello!

I need help in making a few decisions about what parts to use for our lathe conversion to gun-drilling..

We are planning on 1000mm+ of travel, 1 axis, a lot of supports for the "gun drill".

i had in mind two linear guides (axles) and a ball screw in the center for controlling the sled for the gun drill.

I have never made anything like this in my life.. nor have i worked with any custom cnc programming, so all help will be deeply appreciated..

EDIT:
We are only using a 6.5mm gun drill in this machine, so there isn't a lot of stress on the system

[DALEK]

Many years ago, I converted a manual Harrison lathe to gun drilling. Worked quite well. 1000mm deep holes in inconel 600. What lathe are you starting with? I did not use slides, I mounted a motor with the gun drill chuck to the carriage of the lathe and used the lathe leadscrew to feed. The drill and the workpiece were contra-rotating so the hole was always true. What coolant pump are you thinking of using, the pressure needs to be extreme. And be carefull, the chips shoot out of the hole fast enough to go through your skin. You will need to cover the machine.

[thorengebretsen]

we're using an old Mondiale gallic lathe. the reason for using a stepper motor to control feed is because of the feed rate is to high on our lathe..
For coolant we are using a 80bar industrial pressure washer pump!

[DALEK]

My lathe would not feed slow enough. That's why I put a motor on the carriage. I could use a slow rotational speed on the lathe, hence very low feed, and high speed on the drill in the opposite direction. Worked well. Used a Sterling Gun Drills spray mist system.
If you really want to use a stepper, why not connect it to the feed screw you already have. Any linear guides you use won't be as solid as the lathe bed. Don't underestimate the stresses involved, and don't underestimate the mess it will make. I put the gun drill through a few paper coffee cups as I was drilling to try to catch swarf. Some swarf would shoot right through. I was drilling 6.5mm holes also.

[AfricanSwallow]

I'm thinking aloud here, wouldn't it be easier and cheaper in the long run to use EDM instead?
Can EDM drill a small hole, then run the wire through to cut a hole without any cutting forces.

[joeavaerage]

Hi,
those round linear rails are about as stiff as cooked spagetti.

If you want any sort of accuracy you want heavy duty preload bearing cars or square rails. This sort of thing:

https://www.ebay.com/itm/CNC-Router-...c5898194284bbf

Craig

[HoleSpecialists123]

Hello, I am running a Gundrilling shop here in the states and am looking into building my own machine. Could you give me some insight on how your lathe conversion went?