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Seized pivot pin on wadkin AGS 12

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Max Brosi

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Hi all, I'm new on here so thanks for adding me. I've had a look around the site but couldn't find an answer to my problem. I'm restoring a Wadkin AGS 12 saw and the pivot pin on the rise and fall mechanism is well and truly seized. I've removed the grub screws, sprayed it in wd40, applied heat to the casting, tried hammering a brass drift pin in, tried pushing it out with a bridging block and a g clamp, but absolutely no movement. As a last resort I could drill it out and get a new one made, but I'm hoping someone will have experience with this and have good suggestions. Thanks guys.
 

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deema

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I’m afraid once you have tried the punch, heat and penetrating fluid the last resort is to drill them out. When we do this we rebore the casting to ensure we get everything concentric. You will need to make a new pin, I don’t think they are available as a spare any more.
Check the rise and fall rack, most times when this has happened the rack is missing teeth when someone has tried to move the blade up and down.
 

Max Brosi

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Thanks, the rack is perfect, no damage. I'll try the heat, pressure, tap, penetrative oil a few more times first, drilling is a last resort.
 

Inspector

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Instead of WD40 try a 50/50 mix of Acetone and ATF (automatic transmission fluid). I have read that it is much better than most spray can products.

Pete
 

deema

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Our last restore is to stick it in a bucket of diesel over night.
 

Fergie 307

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Plus gas is much better than WD40. A method I have used before if you can position it suitably is to stick a piece of pipe round the hole then fill it with your chosen fluid and leave it overnight.
 

Henniep

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I would discontinue the heat application, you're just carbonising the gunk thats causing the problem. Try a derusting agent or, don't laugh, use coca cola instead of penetrating oils.
 

Chippymint

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I would take it to my local engineering company and for a small fee ask them to press it out using a power press. Some garages have these to.

It's a simple process and they may use heat as well but as the casting is supported properly there is less risk of damaging the casing - which you will find hard to replace. Also they may be able to make you a new pin and seem out the hole. Proper job.
 

KT_NorCal

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I have a '78 AGS10, but I think the design is pretty much identical.... I literally just took that pin out of the saw tonight (actually took it out the side of the saw... haven't had the chance to get the table off yet!) and I'm not sure how it can be seized so completely tbh.

Mine seems to be bronze and it rides on bronze bushings in the casting so I would have to think the AGS12 is similar. I started by tapping it out with an aluminum drift I have for this sort of thing, but wasn't getting much movement and didn't want to get violent with it right away... I took another look at everything and decided to remove the "value engineering" retention plate that that captures the raise/lower trunnion on the opposite end (I need to redesign that... it's just a sad design) first as it looked like the entire trunnion wanted to come out with the pin. Only thing was that in doing so it added a significant amount of torque to the pin just via the weight of the trunnion hanging down. Once I realized that and supported it with my hands I was actually able to just barely pull the trunnion and pin out once I had tapped it out half way by keeping it parallel to the main trunnion while I was doing it.

Anyway, first thing I would do if it is really giving you fits is to take the entire assembly out and bring it to someone with an arbor press. If you are trying to take it out while in the saw though I would try and make sure you keep the trunnions parallel to one another to make sure it's not adding a bunch of pressure to the pin... esp since it looks like your saw is an earlier one with the cast in arbor housing... that must be a decently heavy casting...

Anyway, not sure that helps, but drilling that out would be a bummer.

Also, randomly, does anyone know if the bronze bushings in the raise/lower casting are supposed to be pressed into the casting? I realized when cleaning the ATF fluid out after I got it off that it actually moves a bit (seems like a tight slip fit almost) which I wouldn't think is right...

KT
 

deema

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All of the AGS12 and AGS10’s I’ve refurbished have had a steel pin riding in the cast iron. This is a good combination as the cast iron is lubricating. I’ve never come across bronze bushes or bronze pins. I’ve checked all the manuals for the AGS10, and 12 and also for the later 250/300 and none suggest that they have bronze bushings. I might be wrong, every day is school day after all, but I suspect your machine has had a seized pin, has been drilled out and lined with bronze bushes. I personally wouldn’t combine bronze on bronze for sliding parts and would instead use steel for the pin.
Finding that the pin is seized is not unusual unfortunately.
 

Marischal Ellis

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As above 'Pluss gas' is back in the market...so much better. I use it successfully.
WD40 is glorified paraffin (aero fuel + stuff) and is intended as Moisture Displacement. Paraffin was the 'go to' for almost everything when I was young! Sea water removal, large clocks, cleaning ,fire wood and so it goes on. Almost everyone had a can. Best wishes.
 

KT_NorCal

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All of the AGS12 and AGS10’s I’ve refurbished have had a steel pin riding in the cast iron. This is a good combination as the cast iron is lubricating. I’ve never come across bronze bushes or bronze pins. I’ve checked all the manuals for the AGS10, and 12 and also for the later 250/300 and none suggest that they have bronze bushings. I might be wrong, every day is school day after all, but I suspect your machine has had a seized pin, has been drilled out and lined with bronze bushes. I personally wouldn’t combine bronze on bronze for sliding parts and would instead use steel for the pin.
Finding that the pin is seized is not unusual unfortunately.
You are right it was steel/alloy of some kind. Looked bronze when I pulled it out, but was covered with synthetic ATF so just tossed it in the bucket of Oil Eater. Pulled it out of the bucket earlier tonight to take a closer look and it looks like it has some cadmium or other plating (and some rust). The bronze bearing is definitely original though (it's in both trunnions). I'm essentially the second owner and the saw had sat in a warehouse unused since about 1984/85. Also given that they clearly sprayed absolutely everything green once it was assembled its clear a lot of the bolts have never been messed with. Their spray painting skills wouldn't have qualified them to work at Bently that is for sure. I'll post more pictures in my thread on the AGS10 once I get a moment.

Luckily this one popped right out and other than dimples on the flats from the grub screws it looks completely unworn, so I'm pretty happy. Just have to sort out the loose bronze bushing.

KT
 

deema

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I’d really like to see a picture of the saw and the bush arrangement. It’s a new one to me. Sorry, don’t want to hijack the thread.
 

Spectric

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If you have one try an impact gun, plenty of plus gas and it should move, otherwise as said it is a drill out job.
 

KT_NorCal

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I’d really like to see a picture of the saw and the bush arrangement. It’s a new one to me. Sorry, don’t want to hijack the thread.
I haven't been as good about taking " before" pictures as I should, but I'll take some more and post them on the restore thread for my saw. I'll have more questions anyway I'm sure...
 

Sandyn

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Looking at the picture, I guess the grub screws came out of the two threaded holes. A sanity check, there aren't any other grub screws in there, or anything else?
Does the rise and fall mechanism still work? Do you really need to get it out? If not, I would just accept this pin is not going to move and work around it.

Penetrating fluid and heat usually work after long enough, The key is to try to get any movement in the seized part. Can you grip the end of the pin and try to get rotational movement. I would get an adapter made to inject penetrating fluid under pressure into the grub screw holes.
If you cut the end off the pin, is there enough room to get the rise and fall mechanism off the end of the pin. Or is that seized as well? It would be easy to get a new pin made
Another possibility is to weld a big long handle on to the end of the pin, but it would have to be welded really slowly allowing the pin to cool after each spot weld to prevent the possibility of cracking the cast iron.
Good luck!!
Patience and perseverance and you'll pee a hole in a stone!!
 

Max Brosi

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Thanks for all the replies guys, I tried a vice grips, stilson wrench, map gas, rust off spray, impact drill, mallet and brass drift, and I went to 8 tons of pressure on vertical press. NOTHING! And yes, the grub screws were out. So now it's with a local engineer who will bore out the pin and machine a new one. I've completely taken the rest of the machine apart and I'm going to clean it and repaint it. Funny observation. Map gas torch had absolutely no effect on the old wadkin paint, serious stuff. Has anyone goy any pointers for polishing up the cast iron? So far I've sanded with 80 grit to remove the surface rust.
 

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KT_NorCal

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Thanks for all the replies guys, I tried a vice grips, stilson wrench, map gas, rust off spray, impact drill, mallet and brass drift, and I went to 8 tons of pressure on vertical press. NOTHING! And yes, the grub screws were out.
You must have done something to seriously offend it if it didn't budge under the vertical press.... Will be interesting to see if that was something hanging it up.


So now it's with a local engineer who will bore out the pin and machine a new one.
Given that your model has the integrated arbor housing this is the right thing to do... no one wants to spend extra cash if they can avoid it, but this way the saw won't be damaged and, in all likelihood, will have a much tighter tolerance pin than the original would have been... Never hurts to start off with everything being as accurate as it can be....

I've completely taken the rest of the machine apart and I'm going to clean it and repaint it. Funny observation. Map gas torch had absolutely no effect on the old wadkin paint, serious stuff. Has anyone goy any pointers for polishing up the cast iron? So far I've sanded with 80 grit to remove the surface rust.
This didn't hold over into the green paint era saws... My paint falls off if you even look at it funny and there is zero primer under anything... If the paint is that solid it is probably worth just sanding/scuffing it and using that paint as a base.

I also like that you saw is grey... I'm changing my saw over to grey when I repaint it. Much better looking IMHO.

As far as cast iron. I wouldn't use sandpaper that aggressive on it. Rust is easy to remove with a razor blade on machined surfaces, so I would start with that.

The process I use is:
1. If the rust is really flaky A soft wire wheel on a hand held drill to get the loose stuff off (not a cup brush on a grinder!).
2. Razor blade using any oil handy as a lubricant.
3. If it is a part I can fully dunk in a bin of some kind it then goes into a solution of Evaporust or a dilute solution of citric acid (depends on type of rust). If using citric acid I keep an eye on it.
4. If its too annoying or cumbersome to dunk it gets a polishing with red (fine) then grey (extra fine) 3M non woven pads under a random orbit sander.
5. to kill any rust left in the grain of the cast and/or to lighten any stains I then use a solution of phosphoric acid on it. Will get out some rust stains in machined cast iron, but not others... no rhyme or reason to why it doesn't work on all of them but still always worth a go.

will be following along.
 
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Max Brosi

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You must have done something to seriously offend it if it didn't budge under the vertical press.... Will be interesting to see if that was something hanging it up.




Given that your model has the integrated arbor housing this is the right thing to do... no one wants to spend extra cash if they can avoid it, but this way the saw won't be damaged and, in all likelihood, will have a much tighter tolerance pin than the original would have been... Never hurts to start off with everything being as accurate as it can be....



This didn't hold over into the green paint era saws... My paint falls off if you even look at it funny and there is zero primer under anything... If the paint is that solid it is probably worth just sanding/scuffing it and using that paint as a base.

I also like that you saw is grey... I'm changing my saw over to grey when I repaint it. Much better looking IMHO.

As far as cast iron. I wouldn't use sandpaper that aggressive on it. Rust is easy to remove with a razor blade on machined surfaces, so I would start with that.

The process I use is:
1. If the rust is really flaky A soft wire wheel on a hand held drill to get the loose stuff off (not a cup brush on a grinder!).
2. Razor blade using any oil handy as a lubricant.
3. If it is a part I can fully dunk in a bin of some kind it then goes into a solution of Evaporust or a dilute solution of citric acid (depends on type of rust). If using citric acid I keep an eye on it.
4. If its too annoying or cumbersome to dunk it gets a polishing with red (fine) then grey (extra fine) 3M non woven pads under a random orbit sander.
5. to kill any rust left in the grain of the cast and/or to lighten any stains I then use a solution of phosphoric acid on it. Will get out some rust stains in machined cast iron, but not others... no rhyme or reason to why it doesn't work on all of them but still always worth a go.

will be following along.
Thanks, I've tried the maroon scotch brite pads and the blade method. Both didn't do much. I've already given the table a once over with 80 grit, didn't leave any deep scratches. I guess I'll continue with finer paper and scotchbrite now so. Like the tip about the acid
 

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