Thread: CNC torque screwdriver attachment

Hi all,
On our 3 axis mills we currently make a lot of parts out of various sheets of acetal and PVC from 3mm to 6mm thick. All sorts of shapes and most of the time these parts require screwing down to the large fixture using holes in the parts (can range from using M2 to M4 threads).
One sheet can mean 200 screws or so which we currently do by hand using a Dewalt gyroscopic electric screwdriver on the lowest torque setting.

Does anyone know of a screwdriver attachment we can load in the spindle, set a torque, and run a tapping cycle on all the screws (after inserting the screws a couple of turns by hand first)? The attachment should have a built in spring so it cannot keep driving the screw into the part.
Or do I buy a torque screwdriver and make an attachment myself?

Thanks.

Originally Posted by newtoid1986

Hi all,
On our 3 axis mills we currently make a lot of parts out of various sheets of acetal and PVC from 3mm to 6mm thick. All sorts of shapes and most of the time these parts require screwing down to the large fixture using holes in the parts (can range from using M2 to M4 threads).
One sheet can mean 200 screws or so which we currently do by hand using a Dewalt gyroscopic electric screwdriver on the lowest torque setting.

Does anyone know of a screwdriver attachment we can load in the spindle, set a torque, and run a tapping cycle on all the screws (after inserting the screws a couple of turns by hand first)? The attachment should have a built in spring so it cannot keep driving the screw into the part.
Or do I buy a torque screwdriver and make an attachment myself?

Thanks.

As an aside, could you mount a proper controlled torque driver (IIRC the latest are digital) on a "tapping arm" along with
a feeder bowl, and feed tube ?

Should go very fast.

I've deployed a lot of screw driving robots but don't know squat about integrating things into a CNC mill. In fact, I'm designing 4 robotic cells right now that will use Deprag vibratory bowls and blow feed jaws with Atlas Copco drivers. I would either blow feed or pick the screws from a presenter using a magnetic bit. Blow feeding is expensive, but so is your labor right now. Deprag, Weber, Stoeger, and Atlas Copco are suppliers to look at. They all sell torque controlled drivers that can be blow fed. If you go with a screw presenter, Ohtake makes a bunch that are affordable. I like to press fit a ring magnet onto a torx bit and pick from presenters for lower cost applications. There's no need to start the screw by hand. In fact, that would make it more difficult.

I haven't heard of any off the shelf solution, but if you do the DIY route, maybe a yankee screw driver attachment with a torque limiting bit on the end (like the "Fix it Sticks" torque limiters), so you can just wait for the click when adjusting the Gcode plunge z depth.

Youtube - "Using a Haas VM-6 as lathe and screw driver" https://youtu.be/rLcscD2QaWE

"Let's try using macro variable #1098​ (spindle load) on a Haas control to carefully drive in a screw with programmable torque. We use a standard tap tool with relief in +/- Z and a modified bit holder. The whole idea behind this proof of concept is to automatically clamp Miteebite devices in the future, where you simply cannot use an 120 Kg pneumatic vise (e.g. on a 4/5 axis trunnion)."

Originally Posted by smartcolombyan

I haven't heard of any off the shelf solution, but if you do the DIY route, maybe a yankee screw driver attachment with a torque limiting bit on the end (like the "Fix it Sticks" torque limiters), so you can just wait for the click when adjusting the Gcode plunge z depth.

or use a tapmatic it has a adjustable clutch as well as it has wiggle room to locate in the hex as well as a tad bit of up and down movement

I like the Tapmatic idea. The less you have to DIY the better.

If you want to be extra safe, you can also make your own ball-end allen bits on the lathe with a weak point. I'd probably use unhardened carbon steel like 1018 or 12L14 so they have no chance of rounding out the screw heads.

Originally Posted by Orange Vise

I like the Tapmatic idea. The less you have to DIY the better.

If you want to be extra safe, you can also make your own ball-end allen bits on the lathe with a weak point. I'd probably use unhardened carbon steel like 1018 or 12L14 so they have no chance of rounding out the screw heads.

I did too, but the next morning I was trying to figure out how to remove them. The reversing might be an issue whats your thoughts on that? do they make a left handed tapmatic?

Don't make ball end allens, as the ball ends will get stuck. Radius the end for easy insertion, but make the weak point much higher up so you have enough stub to pull on.