Twist work stops for CNC router tables

[Analias]

I'm looking for work stops I can install in the surface my CNC router work table that you give a twist and they pop up. Press down and twist and they lock below the surface of the work table. Anyone seen these, either for wood working or machining? I would use them for aligning the work on the CNC table to the axis/origin and if designed right might even be used for work holding by biting into the base of the stock.

-Freeman

 

[francist]

Search “twist bench dogs” and you’ll find some, here’s one supplier...

edit: hmm actually I’m not sure now if these go below the surface or not. Might have jumped the gun on my recommendation.

 

[francist]

Okay, these ones go flush but don’t use a twist motion, just a push motion like a cabinet latch. Need pretty deep holes though.

 

[Analias]

I was just at their web site.

It might be easier to make these on the lathe. Two pieces of round, the outside with a single hole drilled for a set screw. The inside piece is has a shaft with a single grove or "thread" that wraps the the length and circumference of the shaft. A single twist would quickly raise or lower the stop.

Does that make sense?

 

[Analias]

Okay, these ones go flush but don’t use a twist motion, just a push motion like a cabinet latch. Need pretty deep holes though.

View attachment 344850

I think you found a good first candidate. Do you have the URL to the page?

 

[Analias]

Ouch $33/each - pretty snazzy for a bench dog. Insert, give the top a twist and it slightly expands into the dog hole to secure it.

I have plans to make a work bench that is similar to a Festool bench, but could be sought enough to hand plan and carve work on. These would be really nice to use for that. I may have to give in and use the Festools dimensions for the hole pattern and 20mm hole sizes.

 

[Analias]

$2 pop-up bench dogs using door latches. Heh, use a ferrous metal for the dogs and you can use the magnets on the latch to hold them.

$2 Pop Up Woodworking Bench Dogs

$2 Pop Up Woodworking Bench Dogs: Greetings Earthly Dwellers, This project is inspired by Veritas Prairie Dogs, these are pop up brass workbench dogs. They are too expensive for me, so I tried to come up with ways to make my own version. I recalled when I was 14ish there was a door …

www.instructables.com

 

[francist]

The pop-up ones I found are called “Prairie Dogs” and made by Veritas. There are a few places that carry them, Lee Valley being the originator at leevalley.com They are a Canadian company but have a US presence and website so you can get them through there. But like I said, other places carry them too. No, not cheap.

For your lathe-made idea, yes a single thread would work although I think it would also be a great candidate if you wanted to try your hand at making multi-start threads!

I think the trick will be getting a good enough fit on the barrel for the accuracy and rigidity you’re trying to maintain but at the same time still making it easily retractable.

 

[spumco]

Headless shoulder bolts.

If you've got a lathe, turn a piece of steel/brass (or whatever) in to a cup shape with a threaded hole at the bottom of the cup. The bore is a close sliding fit to a mating headless shoulder bolt. The cup is pressed in to the workbench dog hole and the bolt screws down in to it. A drop of vibra-tite on the threads keeps it from vibrating (up or down) loose. The close fit keeps stuff from getting down in the hole, and give a bit of repeatability when used as a work stop.

If you wanted to get clever you could countersink the top of the cup and then use flat head bolts to act as a sharp edge to dig in to the stock. Replace with headless bolts if you don't want the bite. Or headed ones with a washer to use as hold-downs.

And... if you make a steep angle thick washer with a taller bolt you now have a wedge-action clamp.

If you're making your own, choose a coarse thread to speed up raising and lowering - but a cordless screwdriver would be really quick to pop a few up/down for each job, espeicially if you threw an o-ring in the bottom of the hole to keep the screw from locking up when you retract it.

If I were making a few of these I'd buy a box of shoulder bolts and turn the heads off... or maybe invest in a rotary broach. Last thing I'd want is some silly blade slots to get chewed up. Hex or Torx drive for sure.

Makes me wish I had a CNC lathe. Oh, wait.... there it is...