Would this work as tail vise scew? (T8, 4 Start acme thread, 3D Printer Screw)

[Jon Crafting]

I'm drawing up plans for a woodworking bench and have been debating different approaches for a tail or wagon vise. I really like the simplicity and smaller form factor of the Veritas Inset Vise, but my budget is limited and I can't justify dropping >$100 on an accessory gadget that could just as easily be replaced by two bench dogs and a pair of sliding wedges.

In my search for different affordable screw options I stumbled on some multi start screws used in 3D printers that might just do the job.

Questions:
1) Is the 8mm screw going to be strong enough?
2) How much weight/pressure can pillow bearings hold?


LINK: T8, 4 Start acme thread, 3D Printer Screw as tail vise

T8 4 start screw and nuts.jpg

If anyone has any experience using these or has an alternative budget option for thicker multi start screws/nuts please share.

-Jon

[Andrew Seemann]

8mm is only 3/8". At that point you could probably just buy some 1/2" thread rod and make a stronger version for less money.

[Peter Christensen]

Only for the very lightest of work. Bench screws are usually in the range if an inch in diameter. Same thing in a metric size is 25mm. 8mm is a little over 3/8".

[Peter Christensen]

You sure it wouldn't be easier to adapt one of the vice screws LV sell? Would the pipe vice work?

http://www.leevalley.com/us/Wood/pag...64&cat=1,41659

http://www.leevalley.com/us/Wood/pag...34&cat=1,41659

http://www.leevalley.com/us/Wood/pag...83&cat=1,41659

[Jon Crafting]

On closer inspection of the Veritas inset vise, the description confirms the threaded rod is 1/2" (12.7mm). Thanks for the quick feedback. I must agree that 8mm is likely too weak.

@Peter Christensen - Thanks for the links to the Lee Valley options, but after shipping and tax those are all out of my budget. I'd really like to keep the hardware acquisition under $20. The smaller form factor of this option, similar to the Veritas one was also a contributing point.

I wish multi start screws were not such a specialty item and priced more reasonably compared to standard threaded rod.

[Peter Christensen]

There is free shipping until the 20th of Feb.

Something to note: A multi-start thread has a steeper lead angle so while faster doesn't apply the same force. It is less.

[Andrew Seemann]

I'd really like to keep the hardware acquisition under $20. The smaller form factor of this option, similar to the Veritas one was also a contributing point.

5/8 thread rod isn't very expensive and would probably work just fine for what you are doing and is likely available the local hardware store. Actually, 1/2 would probably work as well. Acme or square thread are stronger, but something that size doing that sort of thing doesn't need to be super strong. The main thing is that there are more threads per inch in standard thread, so it takes longer to move the jaw than the more coarse thread Acme or square.

[Alan Schwabacher]

Look for a levelling jack, used with scaffolding. For $15 new you can get a 1 3/8" diameter screw 24" long, with nut. This will make a fast acting, strong vise. A leg vise is the easiest to make.

[Jon Crafting]

@Peter - Good point regarding the force of multi start threads. That was actually an additional concern I had about the screw I linked in the OP. While I have seen other woodworkers use 2 start threaded rods for vises, I had not seen 4 start threads used and was unsure at what point the increased action speed would reduce the mechanical leverage to a point the vise was borderline functionless.

@Andrew - Great minds think alike. I've actually been eyeing the threaded rod selections at my local home centers but been holding off in hopes of finding an alternative acme or multi start rod.

While too beefy for what I am looking to do for a tail vise, i have been considering scaffolding/leveling jack screws or barbell rod ends for use in a leg vise.

Thanks for helping me think this through. I will likely update this thread with what I end up going with.

-Jon

[Jon Crafting]

Look for a levelling jack, used with scaffolding. For $15 new you can get a 1 3/8" diameter screw 24" long, with nut. This will make a fast acting, strong vise. A leg vise is the easiest to make.

Hey Alan, looks like I was writing my post where I mentioned these at the same time you were! I will very likely do exactly this for my leg vise, but haven't found a local source for the $15-$20 price range which I know they go for. HD's $35 for 1 seems a bit over priced.

-Jon

[Tom M King]

Also, check ebay for Acme threaded rod. I bought a 4' length of 2" stainless steel with 4 tpi for less than a hundred bucks. I had been watching for a couple of nuts that would work, but a tap came up, the right size, and pitch, and no one else bid on it. I have some blocks of Delrin, and oil filled nylon that I intend to make the nuts out of, but haven't had a chance to work on it yet. I think I paid 30 bucks for the tap. Sometimes it's worth playing the auction game.

Here's a picture of the tap. It's a starter, and finisher on the same tool. It's brand new, still in plastic dip. I'm sure one at retail would be a lot more than 30 bucks.


And here's the Acme stainless rod. Size L glove hand in both pics.

[Derek Cohen]

Jon, if you are truly motivated, and willing to make tools to make tools, then you can make your own thread and vise from wood: http://www.inthewoodshop.com/ShopMad...nAWeekend.html

There are plenty of videos - on Youtube no doubt. I have not looked - that will guide you through making a screw and its mating thread. Here is one I made (I've done several) ...





As the link above show, this was for a mini bench I used at woodshows for demonstrations ...



The easier way would simply be to purchase a few 1/2" or 3/4" bolts and nuts at your local hardware store. But where is the fun in that?

Regards from Perth

Derek

[Andrew More]

These are perfect for vises.

https://www.homedepot.com/p/MetalTec...P24H/203504550

[Alan Schwabacher]

These are perfect for vises.

https://www.homedepot.com/p/MetalTec...P24H/203504550

They are, but as noted above, they are available for less. Scaffoldmart dot com has them for $15, but whether that's a good place to get one may depend on shipping. You could also check out a place that rents scaffolding, since one can imagine damage that would not hurt its use as a vise -- you might get it for free.

Also take a look on youtube for "Pask makes". He uses these screws for leg vises, uses one to make a threadbox to cut large threads in wood, and among other things makes a tail vise from an old scissors jack.

[Richard Coers]

Only for the very lightest of work. Bench screws are usually in the range if an inch in diameter. Same thing in a metric size is 25mm. 8mm is a little over 3/8".

3/8" equals 9.52, so it's less than 3/8"