Feasibility of fabricating part of a universal joint?

[sploo]

I have a partially broken universal joint from a ~40 year old table saw (see below):

The central section had seized solid, and unfortunately adjusting the blade tilt (using the threaded rod + UJ shown above) has caused part of one end to shear off.

It looks to be 3/4" OD, with a 5/8" bore. I'm thinking I could drill and (likely shoddily) mill out enough from a piece of 3/4" steel rod to make a replacement for the damaged end. However, would mild steel (e.g. EN1A or EN3B) be strong enough? I can get some EN8, but would that be feasible to machine with HSS drills and cutters? (yes - I am a noob metalworker)

 

[dzj]

Have you tried file testing the damaged part for hardness?

 

[sploo]

Not yet. I took it to a garage today in the hope it might be possible to weld some metal on for me to re-drill and shape, but as they reckon that won't work I can have a go with a file tonight.

How would EN8 respond to a file? Is it hard enough that it'd just skate over?

 

[dzj]

If it's heat treated, it'll leave less a trace than on mild steel.

I'd try making it from a round tube of similar diameter.
If it's for tilting the blade, it won't be used that much anyway, so you probably could get away
with mild steel.

 

[sploo]

Thanks. OK, well I've ordered some and will give it a go.

 

[novocaine]

jelly bean part, unless you want it to be identical buy a new one.

https://uk.rs-online.com/web/c/pneumati ... al-joints/

doesn't need to be 3/4, just as close as possible so you can use a 20mm metric if you can't get one of them colonial parts.

 

[sploo]

I did spend some time trying to see if I could source a replacement. I can get an "original" spare, but it's quite pricey.

Most ones I could find with the right ballpark of bore have too large an outer diameter to fit into the mechanism.

This https://uk.rs-online.com/web/p/universa ... s/2645368/ would be almost ideal (obviously I'd have to bore my own centres) but the cost isn't that much cheaper than the "proper" spare.

 

[Ttrees]

Would it not be easier to get a wee bit of plate and weld it to the piece?

 

[sploo]

Would it not be easier to get a wee bit of plate and weld it to the piece?

I have a feeling that would prevent it from rotating (the extra thickness would catch on the opposing "fingers"). I also don't have a welder, so somewhat moot

 

[Ttrees]

By chance there's a welder for the same price as that part your looking at on gumtree, where you are
https://www.gumtree.com/p/welding-equip ... 1312723613

 

[sploo]

By chance there's a welder for the same price as that part your looking at on gumtree, where you are
https://www.gumtree.com/p/welding-equip ... 1312723613

"Strike the arc and you're in the dark" :wink:

(I say that - but I've never used one so wouldn't have a clue where to start. Probably not a rabbit hole I want to go down right now; especially given all the other restoration projects that are taking my time)

 

[Ttrees]

The arc welder is very much, a most important tool for machinery restoration IMO
You probably want one anyway for making up mobile bases for the machines.
Steel is a heckuva lot cheaper than timber, like a ten or fifteen quid for a 20 foot length of angle iron.
Not really any learning curve as with timber because if you screw up you can just go back and fix
up anywhere you burned through.
You can see it as a rabbit hole ,or another facet to your craft depending which way you see the glass as.
Good luck
Tom

 

[DTR]

The arc welder is very much, a most important tool for machinery restoration IMO

Really? What for? As most vintage machines are cast iron I'm not sure what exactly you might be welding? I've restored a few machines, but the only thing I could have used a welder for is filling in the "smile of shame" on a pillar drill table. Not that I wouldn't want a welder for other jobs, just not restoration.

 

[sploo]

The arc welder is very much, a most important tool for machinery restoration IMO

Really? What for? As most vintage machines are cast iron I'm not sure what exactly you might be welding? I've restored a few machines, but the only thing I could have used a welder for is filling in the "smile of shame" on a pillar drill table. Not that I wouldn't want a welder for other jobs, just not restoration.

Indeed. I think this is the first time I could have put a welder to use with restoring old machinery. Not saying it wouldn't be useful for some types of repair; just not the sort of things I've done.

I would like to learn to weld as I think it'd be a useful skill; it's just that it currently ranks below:

• Restoring two table saws
• Restoring a planer thicknesser
• Restoring about 15 old hand planes
• Learning how to use a metalworking lathe
• Starting to do some wood turning again
• Making that box the wife keeps asking me for
• Finishing building the kitchen

I will get round to it. Maybe not in this lifetime though :wink:

 

[Ttrees]

All the machines I've bought used needed some work with the welder.
Lets see, in order of appearance....
Griggio bandsaw needed a bracket made to hold the trunnion down as table was only held on with a g-clamp.
Filled in the enlarged holes on the table for the fence rail and made the whole fence and welded up another wee bracket to the table for switch mounting. mobile base

Startrite saw needed a new slot cut into the motor keyway so filled in the slot at the edges as over 5mm had worn away and filed it again.
mobile base

Magic tablesaw needed some new teeth in the rack and pinion, probably only the tip of the iceberg.
Electra Beckum 315 needed some guides, mobile base

Wood lathe could do with some work, quite a bit, if I want it to be more precise for drilling, or turning metal.
Not to mention stand for the drill and mobile bases to be made yet etc
Probably plenty of stuff I'm forgetting

 

[sploo]

All the machines I've bought used needed some work with the welder.
Lets see, in order of appearance....
Griggio bandsaw needed a bracket made to hold the trunnion down as table was only held on with a g-clamp.
Filled in the enlarged holes on the table for the fence rail and made the whole fence and welded up another wee bracket to the table for switch mounting. mobile base

Startrite saw needed a new slot cut into the motor keyway so filled in the slot at the edges as over 5mm had worn away and filed it again.
mobile base

Magic tablesaw needed some new teeth in the rack and pinion, probably only the tip of the iceberg.
Electra Beckum 315 needed some guides, mobile base

Wood lathe could do with some work, quite a bit, if I want it to be more precise for drilling, or turning metal.
Not to mention stand for the drill and mobile bases to be made yet etc
Probably plenty of stuff I'm forgetting

Buy better machines.

(joking)

 

[Inspector]

If it were me and I couldn't find a similar U-joint even from a socket set, I would take it to a welder that was good with TIG welding. He would be able to either take a small piece of metal and replace the broken ear with it or build up the existing ear with weld. Then you take it home and reshape it with files etc., re-drill and possibly ream the hole to size. The repair will likely outlast you.

Pete

 

[sploo]

If it were me and I couldn't find a similar U-joint even from a socket set, I would take it to a welder that was good with TIG welding. He would be able to either take a small piece of metal and replace the broken ear with it or build up the existing ear with weld. Then you take it home and reshape it with files etc., re-drill and possibly ream the hole to size. The repair will likely outlast you.

Pete

That was my initial thought; but my local garage reckoned if they put some weld on the end it'd just break off. I assume they'd be using a MiG welder though?

 

[Inspector]

You need a welder in a fabrication shop. Something like a shop making restaurant sinks and counters or guys that work on boats or make machines. A garage mechanic unless they do bodywork and custom cars don’t do enough to have the skills. A good welder could even braze a piece on with oxyacetylene that would hold.

 

[AES]

Agreed inspector, but just as you say, the OP needs to find a SKILLED welder who welds day-in/day-out, ideally with TIG, but probably, oxy/acy would do, depends on the material.

Unless the OP finds such a specialist welder, the local garage or blacksmith (if any) is unlikely to have the skills. The side walls of that UJ look pretty thin, and O/A the whole joint doesn't look very big to me.

There's a member on here, unfortunately I've forgotten his name, sorry, who works at a place where they fabricate tanks and vessels in SS for, I think, the food industry. That would be the sort of guy I'd try to find.