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threading end grain

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Forum topic by Karda posted 04-13-2020 06:00 AM 636 views 0 times favorited 25 replies Add to Favorites Watch
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Karda

2368 posts in 1362 days


04-13-2020 06:00 AM

I want to make a double screw vice for the end of my work bench. My bench top is laminated 2×4s. Can I tap the end of the 2×4s for 3/4 or 1” threaded rod. Being end grain I am not sure


25 replies so far

View Sylvain's profile

Sylvain

1053 posts in 3308 days


#1 posted 04-13-2020 01:19 PM

IMO no

Bore one horizontal hole for each threaded rod 5” deep.
Make two vertical holes (from above or from below) 4.5” away from the edge meeting with the holes and slide a metal bed nut in each one;
Screw the rods into the nuts. You might have to put a nut (in a counterbore) to lock the rods.

The 4.5” away from the edge is to resist shearing along the long grain.

example of bed bolt nut:
https://www.amazon.co.uk/Barrel-Cross-Slotted-Centre-Furniture/dp/B071Y3VR77

If you can not find those round bed bolt nuts for your rods, try to find square nuts; then you make mortises instead of round hole to slide the nuts in. The square nut must not be able to turn in the mortise.

-- Sylvain, Brussels, Belgium, Europe - The more I learn, the more there is to learn

View Robert's profile

Robert

3800 posts in 2289 days


#2 posted 04-13-2020 01:56 PM

Yes it should work ok. The biggest issue is going to be getting both rods perfectly parallel.

IMO you will be better off purchasing a vise.

-- Everything is a prototype thats why its one of a kind!!

View tvrgeek's profile

tvrgeek

1008 posts in 2458 days


#3 posted 04-13-2020 02:03 PM

Being softwood is as much a hindrance as anything. Are you planning on having the rods move in and out of the bench, or are they fixed. If fixed, then a lot of reinforcements work from inserts to running a dowel in cross-grain. But if yo are going to tap the endgrain and have the threads move in the bench, then threaded rod does not have near deep enough threads to use in softwood. I would consider another design. Leg vise, buy a good end-vise kit, but an Iron vise etc.

View Lazyman's profile

Lazyman

5677 posts in 2196 days


#4 posted 04-13-2020 04:00 PM

I think that the biggest problem is that standard threaded rod has too fine of a thread for a durable thread in wood, especially in softwood. Not saying it won’t work but it may not work as well as a tap and thread box with a pitch and TPI designed for wood. A better option for the threaded rod might be to cut a mortise a few inches back from the edge into which you can insert and epoxy a nut and washer in place or at least make it so it cannot fall out if you remove the screw.

You might also look at some of the DIY vises that use bar clamps. There are probably several posted on Lumberjocks. Another option is to make a Moxon vice you can clamp to the top of your bench. Several ways to skin a cat (with apologies to cat lovers).

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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Karda

2368 posts in 1362 days


#5 posted 04-13-2020 05:52 PM

the threaded rod once screwed into the bench will not come out, they will be epoxied in. i will put a good layer of epoxy on the threads screw it in as tight as I can and let it dry. The other plan is it put one on the side. How can I make a vise with a bar clamp, the clamp will be well below the center of the jaw. The major clamp action will be on the bottom of the jaw where it will not do much good. All of the videos I have seen of this type of vise are on thin top tables. Remember my 3” table top rests on the edge of a 2×4

View johnstoneb's profile

johnstoneb

3147 posts in 2981 days


#6 posted 04-13-2020 05:56 PM

If you are going to glue them in you might get away with it. Another idea would be to drill a smooth hole epoxy the rod in then pin it from the side in a couple of places.

-- Bruce, Boise, ID

View Lazyman's profile

Lazyman

5677 posts in 2196 days


#7 posted 04-13-2020 07:01 PM

If you are going to permanently epoxy it in, it will work fine. No need to pre-tap it really. Just drill a pilot hole and drive it in part of the way, just to make sure it will cut its way in, and back it out. put some epoxy in the hole and a little on the rod and drive it in until it bottoms out. If you want a little extra holding power so the vise doesn’t pull it out, you can drill a hole through it from the bottom and drive and epoxy a pin into it. I would drill that hole before you drive the rod in and once the rod is in, drill through the rod.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View JohnDon's profile

JohnDon

125 posts in 1978 days


#8 posted 04-13-2020 07:58 PM

I read someplace that using CA to coat threads tapped in weak wood will strengthen them. It works great for for me with small taps (leveling set screws in MDF table saw throat plates). Not sure how well it would work with big threads, but might be worth a try.

View Karda's profile

Karda

2368 posts in 1362 days


#9 posted 04-13-2020 10:38 PM

ok thanks

View Sylvain's profile

Sylvain

1053 posts in 3308 days


#10 posted 04-14-2020 05:50 PM

Lee Valley sells a pipe vise

with a pipe vise, the travel is only limited by the available length of the pipe .

So you can make the movable jaw as thick as you want without loosing clamping capacity.
This means the thick jaw will not flex even with a thick bench-top.

As other have said, standard threaded rods have a much too fine pitch. It would be frustrating.
You will notice, the pipe vise is semi quick release/setting as you can unlock the pipe.

-- Sylvain, Brussels, Belgium, Europe - The more I learn, the more there is to learn

View Karda's profile

Karda

2368 posts in 1362 days


#11 posted 04-14-2020 09:00 PM

ok I’ll keep that in mind

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Karda

2368 posts in 1362 days


#12 posted 07-04-2020 06:25 AM

what size drill should I use to tap for a 3/4’’ threaded rod into end grain thanks Mike

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GrantA

2687 posts in 2216 days


#13 posted 07-04-2020 11:46 AM

Mike you should really rethink your threaded rod choice. Acme rod (and corresponding nuts etc for the other end) are easily available, just not at the local box store. You get a nice big coarse thread for better purchase in the wood AND a nice big coarse thread so you’re not turning a handle 100 times to move it 3 inches

View Lazyman's profile

Lazyman

5677 posts in 2196 days


#14 posted 07-04-2020 12:12 PM

Look at a dumbbell for a cheap source of acme type threads and can cut it to get 2 for the price of one. It will even come with a nut. I’ve seen several DIY vises done with these.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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MPython

280 posts in 621 days


#15 posted 07-04-2020 01:14 PM

This might give you some ideas:

https://ibuildit.ca/projects/wooden-vise/

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