Hillbilly tapping drive

[BuckeyeDennis]

In case you're wondering about the title of this thread, I was born and raised in rural Tennessee. And given the contraption that I'm about to share, I seem to be getting back to my roots! No actual woodworking was involved, so I figured this thread didn't belong in one of the woodworking subforums. But it is yet another example of the versatility of a Shopsmith.

For the project at hand, I had a number of small 3D-printed plastic cylinders that I needed to tap -- these are for a fixture that I'm working on. I hand-tapped the first few cylinders, but that was a PITA. And worse, I couldn't reliably keep the tap dead-true with the cylinder. If I started it at a slight angle, it would tap right through the plastic at a slight angle, even though there was an accurate bore for it to follow.

Recalling some earlier threads here, and having no desire to spend the better part of a G-note on a proper tapping head and mounting adapter, I decided to try using my Mark V headstock as a big ol' tapping head. So I mounted the tap in a chuck on the tailstock chuck adapter, a 6" faceplate on the auxiliary spindle to use for a hand drive, and my G3 chuck on the main spindle to hold the workpieces. With the headstock unplugged, I "chased" the threads by holding the quill lever in my right hand and cranking the faceplate with my left. And I got nice clean and true threads.

Faceplate drive.JPG (419.6 KiB) Viewed 23635 times

But after tapping a few of the cylinders, I got tired of cranking the faceplate by hand. I was almost tempted to "blip" the headstock on under power, to tap faster. But good sense prevailed, especially when I realized that I'd have to unthread the workpiece by hand anyway.

Then, somewhere deep in the hillbilly part of my brain, it dawned on me that I already owned a perfectly good low-speed reversible drive. All I had to to was couple it up.

Hillbilly drive.JPG (432.49 KiB) Viewed 23635 times

It worked great! I had the headstock set to low speed, to minimize the motor inertia seen by the hand drill. Even so, gentle squeezing of the variable-speed hand-drill trigger worked best. As for the coupler, it's nothing but a long hex screwdriver bit, mounted in another SS chuck.

In drill-press mode, you'd want to put the tap in a chuck on the main spindle, of course. And unless you're a contortionist, a right-angle drive on the hand drill would probably be in order.

[dusty]

I have saved that last photo to be put in my notebook.

[jsburger]

Absolutely ingenious!!!

[reible]

This resembles something I do. But the addition of the drill brings it to another level!

I have a crank that I got somewhere and it just happens to have a 5/8" bore so it fits the shaft and the handle folds in so I can use it with or without the handle. There is a post somewhere where I showed this.

This works even better with the powerpro as there is a lot less drag on the spindle.

Now the only other thing that I have found helpful is to reduce or eliminate the spring tension in the quill. Back it off a couple of turns or all the way and you loose that pull back all together. If I have only one part to do I don't worry about it but if I have a few then it really so simple and effective that it is worth it.

Ed

[reible]

https://www.shopsmith.com/ss_forum/view ... ank#p47565

Some where else I show tapping with it????

Anyway as you see not everyone loved the idea because of the fact it could get left on when the shopsmith gets powered up, it would be much worse with the drill being spun around......

Ed

[jsburger]

https://www.shopsmith.com/ss_forum/view ... ank#p47565

Some where else I show tapping with it????

Anyway as you see not everyone loved the idea because of the fact it could get left on when the shopsmith gets powered up, it would be much worse with the drill being spun around......

Ed

There will always be naysayers. Maybe if you don't notice something that obvious you shouldn't be using power tools.

[BuckeyeDennis]

This resembles something I do. But the addition of the drill brings it to another level!

I have a crank that I got somewhere and it just happens to have a 5/8" bore so it fits the shaft and the handle folds in so I can use it with or without the handle. There is a post somewhere where I showed this.

This works even better with the powerpro as there is a lot less drag on the spindle.

Now the only other thing that I have found helpful is to reduce or eliminate the spring tension in the quill. Back it off a couple of turns or all the way and you loose that pull back all together. If I have only one part to do I don't worry about it but if I have a few then it really so simple and effective that it is worth it.

Ed

I’m pretty sure that I got the basic tapping idea from one of your posts, Ed. And that’s a great idea about backing off the spring tension — it would have saved me even more time. The spring didn’t bother me while tapping in, as I didn’t mind putting a bit of exta pressure against the un-threaded plastic. But tapping out, I was worried about damaging the last few threads when extracting. So I stopped turning with a good number of threads engaged, unclamped the chuck jaws, and finished unscrewing the workpiece by hand.

I have another question that you guys might be able to help me with. Originally, I was going to couple the hand drill to the idler shaft, to get lower tapping speeds with more torque, and to further reduce the reflected inertia from the motor (which changes as the square of the drive ratio). So I took off the drive hub, only to discover that none of my chucks or arbors would slide onto the idler shaft. I measured the regular spindles at about 0.624” with my calipers, but the idler shaft measured 0.627. Is this normal, or is my idler shaft out of tolerance?

[BuckeyeDennis]

BTW, it wasn’t a hex “drill bit” that I used to couple the hand drill, it was a hex screwdriver bit. I edited the original post to correct that.

[jsburger]

This resembles something I do. But the addition of the drill brings it to another level!

I have a crank that I got somewhere and it just happens to have a 5/8" bore so it fits the shaft and the handle folds in so I can use it with or without the handle. There is a post somewhere where I showed this.

This works even better with the powerpro as there is a lot less drag on the spindle.

Now the only other thing that I have found helpful is to reduce or eliminate the spring tension in the quill. Back it off a couple of turns or all the way and you loose that pull back all together. If I have only one part to do I don't worry about it but if I have a few then it really so simple and effective that it is worth it.

Ed

I’m pretty sure that I got the basic tapping idea from one of your posts, Ed. And that’s a great idea about backing off the spring tension — it would have saved me even more time. The spring didn’t bother me while tapping in, as I didn’t mind putting a bit of exta pressure against the un-threaded plastic. But tapping out, I was worried about damaging the last few threads when extracting. So I stopped turning with a good number of threads engaged, unclamped the chuck jaws, and finished unscrewing the workpiece by hand.

I have another question that you guys might be able to help me with. Originally, I was going to couple the hand drill to the idler shaft, to get lower tapping speeds with more torque, and to further reduce the reflected inertia from the motor (which changes as the square of the drive ratio). So I took off the drive hub, only to discover that none of my chucks or arbors would slide onto the idler shaft. I measured the regular spindles at about 0.624” with my calipers, but the idler shaft measured 0.627. Is this normal, or is my idler shaft out of tolerance?

If the drive hub fit I am not sure why none of your SHOPSMITH parts would not fit. 0.003" (actually 0.002" above the nominal diameter) should not be any where near out of tolerance.

[reible]

Tried 2 drill chucks on one of my machines and they both fit on but they want to go on too far and contact the plate. Didn't try to tighten them but perhaps the design was such that they didn't want people to use that shaft for anything but a power take off??

Ed