# Feasibility of fabricating part of a universal joint?



## sploo (24 Sep 2018)

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)


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## dzj (24 Sep 2018)

Have you tried file testing the damaged part for hardness?


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## sploo (24 Sep 2018)

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?


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## dzj (24 Sep 2018)

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.


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## sploo (24 Sep 2018)

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


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## novocaine (24 Sep 2018)

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.


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## sploo (24 Sep 2018)

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.


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## Ttrees (25 Sep 2018)

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


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## sploo (25 Sep 2018)

Ttrees":1dwd2h74 said:


> 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


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## Ttrees (26 Sep 2018)

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


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## sploo (26 Sep 2018)

Ttrees":3qag72i1 said:


> 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)


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## Ttrees (26 Sep 2018)

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


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## DTR (27 Sep 2018)

Ttrees":2pfq3dp0 said:


> 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.


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## sploo (27 Sep 2018)

DTR":bbulbv52 said:


> Ttrees":bbulbv52 said:
> 
> 
> > The arc welder is very much, a most important tool for machinery restoration IMO
> ...


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:


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## Ttrees (27 Sep 2018)

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


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## sploo (27 Sep 2018)

Ttrees":h0vmafn3 said:


> 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
> ...


Buy better machines.

(joking)


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## Inspector (27 Sep 2018)

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


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## sploo (27 Sep 2018)

Inspector":ob01iuyn said:


> 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?


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## Inspector (27 Sep 2018)

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.


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## AES (29 Sep 2018)

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.


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## Ttrees (30 Sep 2018)

I'd just simply use the arc welder for that, presuming it can be disassembled?
Tom


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## sploo (1 Oct 2018)

It's 19mm (3/4") OD, and about 65mm (2.5") long; so pretty small.

I've not been able to coax any of the pins out of the central section on this one, but it can be "coaxed" apart.


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## chaoticbob (2 Oct 2018)

sploo":2lnluojs said:


> 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)



I may be missing something sploo, but if it were me I'd machine a replacement from solid bar - not too difficult as you have a mill? Why do you think your effort would be shoddy? EN1A or EN3B should be fine, EN8 probably overkill for this application as there is no need to harden. I'm willing to bet a small sum that the original has lasted 40 years without being made from fancy steel. All will machine with HSS cutters.
Rob


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## sploo (2 Oct 2018)

I have some solid bar of the right diameter. I don't have a mill (or metalworking skill) 

I've got a couple of ideas of how to make a replacement part (including cheating and doing the milling work - slowly - on my CNC router).

I have found a couple of local fabrication places though, so I do plan to contact them to see if they could weld a bit onto the existing damaged part.


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## novocaine (3 Oct 2018)

You could make that by hand with a pillar drill and a hand saw in an hour or so (ok maybe 3). 2 cross drilled holes one for the joint pin and one to form the bottom of the tangs (3 as you'll want the roll pin too), cut down to form the tangs, maybe file out the bottom, no reason to not just leave it round though, give it a bit of shape on the ends then drill the centre bore. you could drill the centre bore first if you want but I'd do it last.


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## sploo (3 Oct 2018)

It had crossed my mind that a bit of careful drilling (drill press and lathe) and a bit of hacking with a metal saw and files would probably produce something that'd work.

I do now have a small metal lathe, and I have a cheap compound slide that I may be able to mount to the lathe's slide - in order to give me vertical travel, so I'd have a poor man's mill.

Many ways to skin a cat; just need time and talent...


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## heimlaga (4 Oct 2018)

I rekon it would be possible to cut of the old ear below the hole and then weld a new piece of flat bar in place. Then grind and file it to shape. Then heat it to red hot and bend it open just enough to let the central piece slid in. Then heat it again and slid the central piece in place and carefully hammer or press it together.

Another way would be to turn a new fork and then rough out the "milled" slot with angle grinder and file it to size. 

I have repaired worse things than that.

My welder in a 200 ampere three phase rectifyer type DC stick welder. Made by Unitor in Norway in the 1960-ies. 
I rekon the welder itself has to be one of the very few machines I own which have never required any welding on it. I have fabricated some new copper parts for it but that is another story.


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