Extending axles with coupling nuts, rods - thread-locker or weld?

Submitted by hiryuu75 t3_z845ev in DIY

EDIT: This got more attention than I was expecting, and a lot of great comments - I've got some hardware exploring to do, but thank you all! :)

I'm building a larger cabinet for an older table saw, and the control wheels for the blade height and blade tilt need to have their axles extended by inches to reach the new outside walls of the cabinet. At a glance, I thought a threaded rod and coupling nut would be the answer, but I need to make sure the turning action of the wheel doesn't unthread the coupling hardware. My preference would be to have the pieces spot-welded, but I wondered if it would be sufficient to use a (semi) permanent thread-locking compound instead. I don't have any hands-on experience with materials like that, and was unsure if they would hold up to the modest torque that would be involved in spinning the wheels to move the saw.

I'm already going to have to have the new rods cut-to-length, and drilled for the back-pin for the wheels (see pics). Thoughts? If I can avoid the welding job, great, but I think it's likely a must for this.

Axle with the coupling nut and extension rod.

Original axle and wheel mount.

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Comments

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Fine_Field8751 t1_iy9nual wrote

Red Loctite (requires heat to remove) would likely hold it just fine On it’s own. Even blue loctite probably would.

Red loctite and jam nuts together on either side of the coupler would be very unlikely to come loose.

https://en.wikipedia.org/wiki/Jam_nut

46

_vlad76 t1_iyaefob wrote

Does red loctite still come in a blue bottle?

9

elkarion t1_iyanzr5 wrote

no that's the other brand loctit had blue in the red bottle.

9

MyMomSaysIAmCool t1_iyacpka wrote

Another option is superglue. If you ever want to remove it, a little heat from a propane torch is all that's needed to make the superglue release its bond.

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Enchelion t1_iyal75z wrote

Some of the blue loctite versions are cyanoacrylate glues. Superglue (the brand) also makes threadlocker.

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Alt_dimension_visitr t1_iybvf02 wrote

And in a pinch, nail polish. Never would have thought I needed that info, but some day you might. Came in handy for me once

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ItsGermany t1_iyakau0 wrote

Blue locktite with a tightend nut is pretty tough, I think I would hold just fine. Has held on my heavy duty bike for like a year now, with similar twisting a ton from a trailer. It is wheels on a table, I thing you are good with countered nuts to be honest, they get super tight and don't separate.

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thblackdeth t1_iya3c01 wrote

My preference is a jam nut. Just put another nut on and tighten it, ideally one on both sides of the connection. They use it for tie-rods on cars, it should hold the table saw.

Main advantage is it's easy to take apart, And doesn't require drilling or tapping what you have

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Freefall84 t1_iyahke1 wrote

Might not be enough thread for a full sized jam nut a half nut should do it. Stick a bit of loctite on there to be safe and it should be scookum as frig.

17

Westerdutch t1_iycw9nh wrote

I too love me a good jam nut but in an environment with high vibrations and possibly temperature changes there's no beating a jamnut with locktite. Still can be undone without having to permanently change anything on the device, just need one more step (heat) to get it apart when you need to.

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Dosko2 t1_iy9nv5p wrote

Through drill with a cotter pin so you can take it apart if needed.

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hiryuu75 OP t1_iy9oszx wrote

Oh, hadn’t considered that. If I can make it a tight-enough fit for the pin, there wouldn’t even be any play in the rod. Thanks for the idea. :)

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jeffersonairmattress t1_iya3tu8 wrote

That is what roll pins or taper pins are used for. You likely don't have a tiny taper reamer so use a roll pin.

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ThreeBlurryDecades t1_iya8ntr wrote

As the other poster said, use a roll pin. I would use blue loctite anyway, tighten your thread, then drill for a small roll pin. Will last forever, but could be taken apart with a punch and a bit of grunt if you had to.

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txredgeek t1_iy9np8c wrote

Blue Loctite would probably be fine, red Loctite definitely. As long as you don't plan on taking it apart without significant effort.

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hiryuu75 OP t1_iy9ol1g wrote

The control wheels themselves are just held on by hub nuts (backed against the mount pin). So long as the rods joined by the coupling nut won’t unthread, I’ll be happy. Much thanks! :)

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ImtheDoap t1_iya042o wrote

Use orange loctite...strength of red...removal ease of blue

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DamnDirtyApe8472 t1_iyaszmx wrote

Put a couple of roll pins through the coupling to lock it. You can always punch them out if you ever need to take it apart

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fantompwer t1_iy9rcvs wrote

Set screws on the coupling nut.

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DarwinIsMyHomey t1_iyb2o56 wrote

Only if they are nylon tipped set screws. Otherwise the threads on the original shaft and all-thread will get totally jacked up.

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therealdilbert t1_iyc7sw5 wrote

extend with a tube that fits over the shaft, with slots that fit over the pin

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WoodntULike2Know t1_iycu7e3 wrote

Your looking at the solution, do the same as how the handle was fixed to the shaft. Drill a hole in each end of the coupling nut and shaft, while in place on the shaft, and stick a roll pin through it. It's reversible and cheap and easy.

Any of the other suggestions (except for welding) will loosen up at some point.

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TheSasquatch9053 t1_iybpiy4 wrote

If you can find bolts long enough, I would suggest using graded bolts instead of threaded rod... Hardware store threaded rod is really soft material (saves cost in manufacturing) and will be bendable by hand in this application unless you have a bearing near the control wheels to keep the operator from applying any bending forces to the extension. 1/2" grade 8 bolts are pretty easy to find and will be much stronger.

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SnixTruth t1_iyc5lk6 wrote

I got a coupling nuts right here!

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root_over_ssh t1_iydbq0s wrote

I'd just put a hole on each end of the nut and lock it in place with set screws

1

sub-hunter t1_iycioi4 wrote

You could swags the coupler - use a large pair of bolt cutters and crimp the fitting onto the threaded rod

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Raul_McCai t1_iyaspw9 wrote

any epoxy will do. Be sure there is lots of thread engagement. If you have to undo it a torch heating it to 250F or higher will degrade the epoxy.

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jay_mald t1_iya6swq wrote

Lock washers.

−6

ShuRugal t1_iyapitl wrote

don't do shit

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adventure_in_gnarnia t1_iyc4nae wrote

they’re useful as a rough torque indicator. Do jack shit for preventing loosening.

They are mostly useful for assembly. you can put an impact on a bolt and nut in a thru hole and hit it without having to trap the nut with a wrench, because the lock washer will “bite”

2