garden tractor wheel lug nuts and studs

I wonder if anyone here can advise regarding wheel studs for a walk behind garden tractor / powered wheelbarrow.

*** I have uploaded many photos into a new album but the album is not currently showing up so I can't link photos to this thread. ***

The machine is somewhat vintage but not antique and is substantial in construction. Each wheel is fitted with four lug nuts and double-ended studs. The studs appear to be 1/2" UNC (13 TPI). Each stud has a long and short threaded section. The long threads are parallel. The short threads look parallel, but possibly tapered. I do not have a threading die or UNC nut to check any of these threads.

Behind the hub, most of the studs are locked with a nut. I have not measured this but it is not 7/8" AF. The lug nuts are 7/8". Some of the studs are too short (or threaded too far through the hub?) leaving too little thread for the lug wheel nuts.
Some of the studs are in poor condition or too short and so I would like to replace them. What should I be looking for? Perhaps I have made an incorrect measurement somewhere, as 1/2" UNC lug nuts do not appear to be available. 1/2" UNF on the other hand appear to be a common standard. The lug nuts do appear to have a tapered thread but I have yet to find any like this online. I'd be happy to replace the lot if needed.

Many thanks for taking the time to read this post.

Brian

Last photo looks wrong to me and combined with the lack of engagement from the wheel nuts I would say the short end of the stud should go into the threaded hub with no lock nut at the back and the wheel nuts will then have a decent length of thread to screw onto.

.

Agreed

The short thread should be tightly screwed into the casting, to be semi-permanent.

... nuts are for retaining/releasing the wheel.

MichaelG.

Edited By Michael Gilligan on 02/06/2020 08:12:19

Agreed - it does look wrong. However, I wonder why they did it like this. As mentioned in my original post, some of the studs are in poor condition and the lug nuts appear to have a tapered thread. Maybe a previous owner found it too difficult to thread the nuts onto a decent length of stud so they reversed them and exposed an absolute minimum amount of thread?

Thanks. The lug nuts appear to be a UNC tapered thread (not UNF) but I can't find anything like this online. Am I just mistaken in the measurement?

Thanks. The lug nuts appear to be a UNC tapered thread (not UNF) but I can't find anything like this online. Am I just mistaken in the measurement?

The assembly should, presumably, look something like this: **LINK**

https://www.gardentractorspares.co.uk/westwood-countax-tractor-rear-wheel-hub-198002000

MichaelG.

UNC taper thread? No such beast exists that I have ever seen. Sure it is not just a worn stud?

Can you clean up the existing studs and Loctite the short ends into the hub and screw the lugnuts on to the longer ends, with wheel etc?

Or use 1/2" UNC high tensile machine set screws screwed through from behind and Loctited in position? Or cut the heads off them and make your own studs?

Seen lots of instances like that where the stud winds out of the hub over the years and eventually becomes very "slack" in the hub.

Normal repair I've seen is a tack of weld on the stud to hub where the stud protrudes through the back of the hub or its peened over.

Often found that the fit of the stud in hub is too loose to be effective for loctite.

Peter

Edited By Peter Bell on 02/06/2020 09:10:32

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ajax you are grossly overthinking this job. This is a utility machine, not a space vehicle. Get yourself a length of 1/2"-13 UNC threaded rod / studding, cut some studs off it leaving 1/4" extra length each side from the total bolted thickness including nuts and lock washers. Put it together with ordinary 1/2"-13 nuts and split lock washers both sides. Do not use flat washers, only lock washers. Job done. Dirt cheap.

If you can get medium strength threaded rod rather than the more usual low strength kind, so much the better. However, even 4 low strength 1/2"-13 studs will withstand tens of thousands of pounds load in shear and tension so no strength worries for your little motor barrow.

There is no tapered 1/2"-13 thread in the UN thread system, and if this thing was made in USA I'd bet money the studs and nuts will be ordinary 1/2"-13. US manufacturers do not faffle about with oddball / exotic threads as a general rule especially on outdoor / agricultural / construction equipment.

Remove all old studs and nuts behind hub.

Throw in skip.

Drill out all threads in hub with 1/2" drill.

Buy 1/2" UNF bolts and proper chamfered wheelnuts.

Install.

Use.

Optional: tack weld bolt heads so only one spanner needed.

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I have seen similar hub problems on 1950s steel "British Hubs" fitted to the back wheels of Dot and Greeves competition machines,where the sprocket bolts were forever coming loose.The previous owner no doubt had found that instead of the wheel nuts coming loose ,the action of the wheels over rough ground rattled the short end of the studs out of the hubs,the wheel nuts did not come loose .to cure the problem he reversed the studs and put a lock nut on the back of the hub, My solution would be to remove the hubs and drill and tap 3 new holes eqispaced between the old ones,as the back of the hub is possibly as cast ,a spotface should also machined around the hole, find some longer studs so that they can be screwed into the new holes and a nut to lock the stud fitted at the back of the hub,the spot face is essential to give a flat seating for the nut,its preferable that the nut is a Nyloc type nut, By drilling new holes you get a good thread,and you have a wider choice when looking for studs as they can be any thread and the holes tapped to suit, it does not matter if the thread is finer than unc, metric or BSF would be ok. Its just that the stud must remain really secure in the hub. I cured my Greeves hub by machining some 5/8 dia steel 1/2 inch long,brazing them in line with the worn threaded bolt holes in the flange then brazed them onto the inside of the spoke flange, It was quite difficult keeping the oxy torch away from the spokes i then used the sprocket as jig to drill through the brazed on bushes,then tapped the bushes and then had a long thread to secure the sprocket bolts, In more recent times I restored both a DOT and a Greeves trials bike though this time it was easier as I did it with bare hubs before I respoked the wheels. Happy days.

What condition are the threads in the hub? could be that they stripped and a previous owner swapped the studs round so he could put a nut each side, that is the only reason I can think of for having the long part in the hub.

There is a photo with the thread gauge positioned right into the thread and pitch looks Ok.

If the female threads are worn or damaged beyond use, then I think this commonly available style of stud would be the obvious replacement: **LINK**

https://www.buycarparts.co.uk/febi-bilstein/7009358

MichaelG.

Thanks for that link. Yes, I agree that it should look something like that.

After a lot of persuasion (heat, hammers, pipe wrench, and welding nuts to the studs to get more grip) I finally removed all 8 studs this afternoon. Your idea is certainly an option, and UNF wheelnuts are so easy to get, but if I choose to drill out the threads I'd rather use the tapered wheel bolts that have been suggested elsewhere.

After removing the "lock nuts" from behind the studs, all but one of the threaded studs took a *lot* of persuasion before they could be removed. However, the good news is the female threads appear to be in good condition. This still leaves the question of why the studs were installed like this but oh well.

The female threads are in good condition. For now I think I will just use 1/2 UNC screws with the original lug nuts, but I might consider this "upgrade" later.

That link you posted doesn't have a datasheet for the part. I wonder what the recommended size and tolerance is for the receiving hole.