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Wadkin 10 AGS "Restoration"

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J-G

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...it says it has a 1” acme. I think however your suggesting of a stub acme sounds spot on.
If that is the case then according to the 1988 Standard the root dia. should be between 0.8600" and 0.8406" and it will be 5 tpi.

Whether or not you are able to measure the root dia. on the spindle in question is debatable but the 5 tpi could be relatively easy.
 
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dephill

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Hi Martin,
Mine is a similar age i think, Machine No. 10"AGS 655783.
It has the old style fence but the new(er) riving knife rise/fall mechanism (I think there might be an even newer riving mech. style involving a linkage but not sure if the pictures i've seen of those are all modded machines)
My saw is all imperial with Whitworth bolts etc.
The arbor is 5/8 with what seems to be a Whitworth LH threadform but i don't have the correct tools to measure it, it looks to be 12tpi (see pic)
40A8AB81-7B7C-4478-BD35-E3E65BF30CF8.jpeg

Your thread looks to have been butchered but i don't see how it could ever have been the same as mine unless it was turned down flat first.

As far as removing the pulley nut, i gave it a good soak in wd 40 and a couple of cycles of heat (not red hot but maybe that's just me) and with the arbor (housing) still bolted into the machine managed to release it with a lot of swinging.
You should avoid gripping it in vices or shoving any bits of bar into the holes on the arbor flange - there is a tool for that.
You need a C spanner:
1618566691636.png

Having said that, I made my own as I'm stingy and i wanted one straight away.
I used the correct size holesaw on a piece of 10mm bar stock i had lying around then drilled and tapped it for an m8 bolt which i screwed in up to its shank and then cut off the head and protruding threads on the other side.
Doesn't look pretty but it works great.
63409ED6-BD06-4078-94E0-40F17CB51610.jpeg

E956604A-C546-4578-8F8B-6ACDA1081230.jpeg
 

J-G

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The arbor is 5/8 with what seems to be a Whitworth LH threadform but i don't have the correct tools to measure it, it looks to be 12tpi
It's certainly 12tpi, 5/8" O/D and Left hand but it is a 'Special' in all respects. The form is 29º (definitely NOT Whitworth) so falling into the 'Acme' oevre but the depth is mid-way between that specified (in the 1988 standard) of full and stub, additionally, being 5/8 O/D - to conform to the standard - it should be 8 tpi.

As I've said before, manufacturers can - and do - please themselves when specifying Stub Acme threads. They are always designed for a specific job and the constraints/requirements seldom align with what some standards committee determined was the 'norm' some years ago.

I pulled the excellent photo you posted into Photoshop and CorelDRAW! to determine the true size (within the constraints applicable) so here's what I found :
Wadkin spindle Dimensioned.png

As you can tell, I enlarged just a small portion from the bottom-centre of your original.
 

dephill

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Hi there,
Duh! I wrote Whitworth when I meant Acme!
You can see how there’s so much misinformation out there when there’s idiots like me writing the wrong words down. I even reread it before I posted to make sure there were no mistakes.
Oops!

Ps. Great work on my photo - makes it very clear.

It's certainly 12tpi, 5/8" O/D and Left hand but it is a 'Special' in all respects. The form is 29º (definitely NOT Whitworth) so falling into the 'Acme' oevre but the depth is mid-way between that specified (in the 1988 standard) of full and stub, additionally, being 5/8 O/D - to conform to the standard - it should be 8 tpi.

As I've said before, manufacturers can - and do - please themselves when specifying Stub Acme threads. They are always designed for a specific job and the constraints/requirements seldom align with what some standards committee determined was the 'norm' some years ago.

I pulled the excellent photo you posted into Photoshop and CorelDRAW! to determine the true size (within the constraints applicable) so here's what I found :
View attachment 108426
As you can tell, I enlarged just a small portion from the bottom-centre of your original.
 

deema

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The older version on the AGS10 all seem to have the same acme 5/8 thread, that’s based on not coming across one so far that doesn’t.

J-G, well done for taking the time and trouble to analyse the thread.
 

Martin_H

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Hi guys, quick response on my phone,

Thanks for Al the efforts in trying to found out the treads on the saw...

My dad came by and took the whole saw arbor to a friend of his who has a metal lathe to clean up the thread

@dephill, nice work on the spanner, I'll have to buy one because I don't have the tools or metal stock to buy one. Let's not hope my feeble attempts to loosen the pully nut have damaged the casting...

As promised I tried to take some pictures of the nut on the saw side. Mind you on the first picture the nut is in backwards because the first threads of the nut are damaged so for now it only goes on backwards...
20210416_181359.jpg
20210416_181605.jpg
20210416_181449.jpg
 

deema

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That’s not an original nut. My best guess its something home made. I don’t believe it’s an acme thread, it’s probably a 5/8 WW, hence all the damage as they just wound it on!
 

J-G

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...Mind you on the first picture the nut is in backwards because the first threads of the nut are damaged so for now it only goes on backwards...
Are you sure "...it only goes on backwards" ?

Further discussion seems to indicate that it is a LEFT HAND thread - certainly dephill's version is and your first image gives me the impression that yours is too. Hopefully the ' friend of his who has a metal lathe ' is savvy enough to realize that and not try to 'repair' it by cutting a right-hand thread. The reason it is likely to be a left-hand thread - whether is is re-cut as Acme or Whitworth - is that there will be a tendency for it to tighten in use rather than 'un-wind'.
 

Martin_H

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Are you sure "...it only goes on backwards" ?

Further discussion seems to indicate that it is a LEFT HAND thread - certainly dephill's version is and your first image gives me the impression that yours is too. Hopefully the ' friend of his who has a metal lathe ' is savvy enough to realize that and not try to 'repair' it by cutting a right-hand thread. The reason it is likely to be a left-hand thread - whether is is re-cut as Acme or Whitworth - is that there will be a tendency for it to tighten in use rather than 'un-wind'.
Sorry I meant backwards as in the big part of the nut on the left in pic1 should be against the blade, it screws on left handed...
 

Stevekane

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Just on removeing the frozen nut, Ive always used Plus Gas penetrating fluid, or similar, not WD40, and secondly you need to get the nut nice and square on a solid metal surface and give the flats a few good wallops, use a drift if you cannot get a clear hit at it, that and soaking in penetrating fluid helps to break up the crud and allows the fluid to do its job.
 

MusicMan

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My own arbor nut on AGS10 is 5/8" diameter
Wadkin AGS arbor thread - 2.jpg
Wadkin AGS arbor thread - 3.jpg
LEFT hand SQUARE thread 12 tpi. Mine does not have the rise/fall riving knife so may be a bit earlier. This is similar to Deema's pics.

The OP's picture is not quite clear enough for me to decide whether it is square or ACME thread. It is most certainly not Whitworth.

A thread file would not help as those assume a Whitworth or ISO tip thread, ie tapered to nearly the end. To clean it properly would need a metal lathe and someone who knows how to grind a tool for a square thread. But if it is only damaged in parts, I would use a small square file and attempt it by hand, on thread at a time. If the bulk of the perimeter is not damaged, this will hold the alignment.

I agree with J-G that it looks like a square thread that some silly person has tried to clean up with a BSW die. And a 5/8 BSW is 11 tpi not 12, so that would not help! If you look at the left hand end the threads do look square.

I think it would be very hard indeed to find a die or chaser for a 12 tpi 5/8 square thread. But a repair might work, as would using those extra washers/spacers. The Wadkin spindle is designed to take a dado head so no harms in using that end of the thread.
 
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J-G

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@MusicMan
Your photo's don't allow me to evaluate more closely because you have a dark background but I suspect that yours is also a STUB ACME form.

The crest width certainly looks narrower than the root width - there are darker bands either side of the 'crest' - If it were a Square form I would expect to see a dark band on one side only - and if you were to measure the thread thickness (with a vernier not a ruler) I think that you will find a difference of something like 0.019" between crest and root.

It is also possible that Wadkin did in fact use a 'modified' square thread (but I consider it unlikely) which would also show the darker line each side of the crest and then the difference between crest & root would be closer to 0.006". It should be very obvious if it really is a square form since even at (say) 0.038" deep you would be able to see no gap at the top when measuring with a vernier.

A square thread form is very difficult to machine in any 'production' environment, Acme is difficult but much easier and cheaper than square or modified square. Stub Acme could be 'Thread Rolled' or cut with a Coventry Diehead using Holozone Dies but I can't tell which from the photo's provided.
 
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