Im also assuming I should be able to lift the blade mechanism by hand, but it seems incredibly stiff ... Are there pivot points I should grease or put wd40 in?
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Im also assuming I should be able to lift the blade mechanism by hand, but it seems incredibly stiff ... Are there pivot points I should grease or put wd40 in?
Looks like either the shaft or the pinion gear has slipped, look at the shaft between the gear and bush where it comes out, it’s shiny which means something has moved
I wonder if the rising mechanism has seized (as I can't lift it manually) - and this has forced the worm gear along the shaft. I'll have another look in the morning.
My next steps are
1. to clear as much saw dust out as possible
2. then try to lift the blade adjuster manually.
3. if I can I will see if I can slide the worm gear back along
4. if I can't raise it I will try and free it up with some WD40
You probably can't move it because the worm gear is hitting against the teeth. The worm gear has come loose and has moved to the end of the shaft. You need to turn the worm gear backwards until it engages with the teeth then, I think, tighten the grub screw that locks the worm onto the shaft. If it is held on with a grub screw that is. No.43 in the exploded diagram is either a grub screw or a roll pin. Looking more closely at the drawing, I'm pretty sure its a roll pin. Which is not good for you. It means the roll pin that secures the worm gear in place has broken. You may have to disassemble the mechanism to replace it.
ok so as I said, I can't comment directly based on that saw but my ST-12, which I expect is similar but different...
As Acco said, your worm drive being off the end of the arbor is because the shaft has slipped through the bushings. One of the locking collets has come loose, and the shaft has then moved through rather than turn and make the mechanism rise. To get that working again, you will need to raise the blade. But the shaft may in fact be working against you, so I'd be trying to push it (gently) up while you look from behind to see what is going on. It unfortunately may need you to remove the rolled pin from the worm drive end to get it back on the teeth. I suspect this because on my saw it's not easy to get the teeth to re-engage and the shaft to return to it's normal place without something moving. Either way your approach seems ok, work slow and don't bend the shaft and you should be good. Keep us updated !
Edit: since I started replying, NCArcher replied. I am pretty sure that the roll pin is still intact and it's the grub screw on the collet of the other side of the housing, near the front of the saw, that has released and allowed the shaft and worm drive to move. Exactly the same thing happened on my saw although it was mainly the tilt mechanism that it was pronounced on. The grub screw in question is usually on the shaft that holds the angle indicator.
Just out in the workshop poking around some more and I get back and there is even more help!
That makes sense about not being to lift it due to the mechanism hitting the worm screw.
I think it may be the collet causing the issue, as just behind the worm screw on the shaft (what I believe to be) the collet is loose.
Just checking my understanding, does mean the turning handle itself will have been pulled into the mechanism?
Here is a wider view of the mechanism I just took. You can see I slid the "collet" down.
Attachment 468569
Attachment 468568
It looks like has gone past the last teeth on the rise. You have manually pull or push the blade so that the gear is engaged. There is not a lot of dust, but it would be a good practice to clean off the dust with the tooth brush or small wire brush. I also recommend a dry lubricant like teflon or graphite over wd40
OK, good news.
Following the advice here I was able to manually lift the blade whilst turning the handle. The gear has now engaged and is turning quite well.
Next step is to identify why the gear ran over to start with. Guessing it is related to the loose collet. I assume if I try to lower the blade again it sill simply roll off again.
Still, nothing better than progress!
There should be a stop, usually in terms of a screw. It might be missing or need adjustment.
great news !
So the collet on the worm gear side will not stop the shaft from pulling out the direction you saw it. The collet on the front side of the saw, holding the pointer, is what will stop it from sliding back into the saw like it did.
On my saw the collet is a large barrel, probably 50mm-ish long, and there's a grub screw holds it to the saw body. Look for something like that !
oh and the collet on the rear is to adjust the worm drive position to be in the best possible pozzie rather than just hard up against the body. That would be a second adjustment if the rise-fall adjustment binds because of the angle; you would release the front side collet a bit so the shaft could move back, and then lock the worm drive side collet hard up against the body. But the angles involved and the fact that the teeth aren't precision items, just cast iron, means you probably won't need to worry about that.
Poundy's on the money. He should be, he's already pulled his apart! Me too! You haven't undone the nut on the handle side of the saw, doing so will allow you to retract the worm gear and shaft back in to the saw. You need to undo the nut and remove the outer eccentric shaft to give you the necessary wiggle room to get the worm gear and central shaft out. As poundy has said if you haven't removed the angle pointer shaft or loosened the grub screw that holds it to the eccentric shaft then the grub screw coming loose is what went wrong to cause the problem in the first place.
When you get it apart take some time to understand how it all works, it's a real the knee bone's connected to the leg bone affair. Put some grease on the worm gear shaft and slide the eccentric shaft on to it, get rid of any squeeze out. As justonething has said use a dry lubricant on the worm gear, WD40 is not suitable for any of the lubrication points on these saws.
OK, that is making sense.
I had removed the turning handle - however the pointer had been removed long before. Below is a photograph of the bits I believe need to remove to pull the shaft back through.
Looking at it I think you can see that the rolled pin is actually sitting inside the base of the saw, not on the outside. Is this further in than others can see on their own saw?
Attachment 468570
that shaft should be out further, yes :) The roll pin is typically outside the line of the face because the wheel has locating slots, and the intent is that this is proud of the front so you can lock it in place.
I'd ease the shaft back while manually lifting the mechanism again, so you get the shaft back as far as possible... then, once you've done that, crank down the grub screw on that long collet you have the picture of just above. Then, have a happy dance