Table saw (Wadkin AGS10) rise and fall problem - jagged

[kirkpoore1]

Peter:

I agree, go with the shim stock first. I wouldn't bother with a new bracket unless everything else fails. Good luck, and I'll be looking for your updates.

Kirk

 

[Peter G Denmark]

Thanks fellows - be sure to let you know.
I look foreward to my eBay delivery, and hopefully getting the saw up and running fairly smoothly. Good table saws are hard to come by for all us non-millionaires .

 

[Guggs]

I love Wadkin machinery ! I've used Wadkin machinery all my working life and all i can say is awesome ! Solid ,simple and heavy ! Once your teething problems are sorted ,you'll have a friend for life !

 

[roadman]

Peter,

I am sorry to arrive so late to your topic.

I have had contact with 3 other Wadkin owners from Denmark, because i was worried about those "broken" pieces, but they had the same plate to hold the glide bracket against the gib way, and their saws worked fine.

I know from the manuals that the older saws had a cast iron L-shaped "motor bracket trapping piece" with 3 set screws that pressed on some kind of pressure plate.

The thing is - the rise and fall action i very smooth (on my saw) from maximum height to about 75% dowm, but the i hangs up - and it's the worm screw that forces the saw down. This is consistent with the problem being play in the pivot pin.

I believe that your saw, and possibly those of your compatriots, use an earlier implementation for capture of the sliding bracket. The newer versions use the combination of the motor bracket trapping piece (should be named sliding bracket trapping piece) and retaining strip (also known as gib). Below is a photo of another 10AGS showing the newer design trapping piece. He acquired the saw without the retaining strip and was not aware when he composed the photo that there was supposed to be a gib-plate/retaining-strip, but depicted clearly is the trapping piece casting matching the diagrams in the PDF manuals.

His saw is from 1962. is yours older?

---
I suspect that the design was changed to the one shown in the several PDF manuals in response to exactly the sort of wear and tear in the field that you have encountered (though decades later): needed was a sounder method of lateral capture of the free rear end of the sliding bracket against the tendency to twist, or hang away from the trunnion when tilted, owing to the weight of the motor and cast components.

It appears from your youtube video that your trapping plate also has at least one locknutted screw to apply pointlike pressure to the bracket. A gib plate is a longer-wearing mechanism than a series of point supports - although, in fairness, my 12AGS also shows some tendency to shudder in the lowest half inch of travel, even though it features the gib-plate design. In my case, I believe the function would be improved by installation of a fourth pressure screw between the middle and lower ones. Even though your trapping piece and machined spacers do not allow addition of a retaining strip, your machine's longevity after repair would benefit from addition of more pressure screws along its length - particularly near the bottom.

The last point concerns the reaming of the new bronze bushing after installation in the sliding bracket, because the bushing as installed will almost certainly be too small in diameter to receive the pivot pin. It is impossible to control precisely the final axial alignment of a bushing when using a hand reamer, yet it is crucial in this application to have the reamed hole's axis be orthogonal to the plane of the casting (and this "shorthand" pre-supposes that the axis of the captive pivot pin remains orthogonal to the machined sliding surface at the rear of the trunnion).

Art

 

[Peter G Denmark]

HeyArt, and thanks for your input.

My saw is a 1976 model, (Nr. 10AGS7615428) and hence on of the younger ags10's out there. Guess the trapping piece is a matter of cutting quality, to gain production value.

I've done a test of this trapping piece idea, by measuring the force it took to pres the slide bracket up against the slide part of the trunion assembly, when it was lowered about 3/4 of the way. I comes out at about 400 kg, so as said before - i might help to make another trapping piece with a gib plate, but it is not a stand alone fix. When snug, i had to use significant force to get i down - which is wrong. The weight of the motor alone should be enough to makes the mechanism fall all the way.

I've called in a favor, so i now have an appointment to give the parts (slide bracket and pivot pin) to a machine shop, that will make the pin fit at the exact 90 degree angle to the bracket. No hand reaming or honing. I'm still worried, but it really can't get worse, since the last 1/4 of the fall mechanism is where 80% of all cuts are made.

 

[roadman]

Peter,

My saw is a 1976 model, (Nr. 10AGS7615428) and hence on of the younger ags10's out there. Guess the trapping piece is a matter of cutting quality, to gain production value.

Wow, I am quite surprised. Thank you for correcting my misunderstanding on the evolution of this mechanism on the AGS10. My saw's machine No. is 12AGS783812 (its cast iron mainframe is in a larger form than your saw, and it uses a one-inch spindle arbor), and it uses the trapping-piece & retaining-strip design, with three large fastening bolts holding the trapping piece to the trunnion rather than the two fasteners used on your AGS10.

It was a clever bit of process economization on your saw to cast the spacers as part of the sliding bracket casting, and then to forcibly separate them after machining for thickness.

I've done a test of this trapping piece idea, by measuring the force it took to pres the slide bracket up against the slide part of the trunion assembly, when it was lowered about 3/4 of the way. I comes out at about 400 kg, so as said before - i might help to make another trapping piece with a gib plate, but it is not a stand alone fix. When snug, i had to use significant force to get i down - which is wrong. The weight of the motor alone should be enough to makes the mechanism fall all the way.

800 lbs (shifting dimensionality as well as units for my comfort)? It's hard to understand how the geometry actually makes the required support greater than rather than less than the weight of the motor, mount bracket, sliding bracket and spindle subassembly.
I suppose that the axis of inadvertant rotation must run approximately between the pivot pin and the bottom edge of the machined contact surface on the rear of the right face of the trunnion casting. On my saw I believe this edge is lower, and even with spindle fully lowered the lever arm is longer between such rotation axis and the top edge of the sliding bracket in contact with the retaining plate...but this aspect of the rise-fall design does seem to be a weakness of some degree across the AGS product line.

the last 1/4 of the fall mechanism is where 80% of all cuts are made.

Do you use a 250mm blade? Does your saw permit more than 75mm of rise/fall?
It appears in your video that the rise and fall limiting screws are both set high on your saw.

If the new bushing and careful shimming and adjustment of the spacing of the trapping piece do not eliminate the problem in the lowest part of the fall mechanism, you may consider restricting the fall with a longer limit screw and using a smaller blade for most work. When you need the greatest depth of cut, then you don't need the last half inch of fall anyway. Hardly a solution, but a workaround.

Thanks again for posting the video. By reviewing it carefully, watching specifically for the man in a gorilla suit, I almost missed the glimpses of the large-plate-form of the riving-knife bracket, which I'd only seen previously in PDF diagrams (generally, AGS saws imported to north america featured only a fixed height splitter).

Art

 

[Peter G Denmark]

Update.

Finally some progress.

I left my bracket piece at a machine shop, to have a new bushing fitted. 4 month later, after serveral calls from me, they told me, that they didn't have a 3/4 inch reamer, and that they only had brass bushings - GREAT (don't want brass bushing, since it's softer, and the existing bronze bushing was worn out).

Anyway - figured out the exact measurement of the bushing to be: Inside dia 3/4, outside dia 7/8, and the length a little under 1 inch, so ordered 2 Oilite Plain Bush 3/4x7/8x1 inch from www.simplybearings.co.uk (great shop).
When i got it, i pressed the old bushing out, and the new bushing in with my homemade ciderpress.

I searched high and low in all local machine shops, mechanics etc. to find a 3/4 inch reamer, with no luck.
Since i had a bushing to spare, i decided to try my luck with a small honing tool, with fine gritt stones, just mounted in my cordless drill. After 45 minutes of honing, and some persuation with a mallet, i got the pivot pin in REALLY snug, and within 1/100 mm square.
Reason i wanted such a snug fit was, that the years of rise and fall action had actually made the diameter of the pivot pin smaller where the bushing rides by about 3/100 mm.

Now - i couldn't spin the pin by hand, but with an ajustable spanner i could orient it the right way, so the notches in the pivot pin lined up with the set skrews that should hold it.

After cranking the rise and fall 10 times, it's really smooth, and NO play. Only thing is, that the bracket plate is gaping about 5/100 mm where it meets the trunion (without the gib). That isn*t because of the bushing, but simply wear and a bit of warp, after years of being mouted with a heavy motor and a sub par gib. I'm not that worried about the 5/100, since it was more like 1 full mm before, and a lot of play.

Now i'm waiting for the 6x20x170mm bronze plate i ordered, so i can make a proper gib plate and gib holder.

That's as far as i got, but will update, and post a video link when i get the rest done.

 

[kirkpoore1]

Good work, Peter. I'm glad to hear you're moving ahead.

Kirk

 

[Peter G Denmark]

UPDATE.

So - the restauration is "done". The saw is not pretty, becuase i didn't paint it. It was the plan, but with all the problems it has had, i need to do some sawing on it, before i do that. I got most of the rust of though .

The rise and fall, and tilt mechanism is ok, but not perfect, but i guess it's just my pride that's hurt by that, since don't thing it will cause a probelm. It's 10 times better than before.

Since the saw is only 86 cm high, i made a mobile base that brought it up to 100 cm, since i'm 200 cm tall. That puts my gentlemans area beneath the table, which is always good.
Put wheels on my jointer at the same time, and brought that up to 100 cm as well, so it can serve as an infeed.

Anyway - here's a video shot a couple of hours ago, if you are interested: http://www.youtube.com/watch?v=fXh_MA5L9Is

(Damn . it's hard to hear your own voice, and thick accent)

Any questions about the saw, the mobile base, the jointer base,etc. please ask - i'd be more than happy to help you out (Milling the groove in the 20mm threaded rod took some jigging up for instance).