RoyG
9th December 2015, 09:35 AM
About a year ago, I sold an old 10 inch Carbatec Table Saw that was surplus to my needs. The saw was in pretty good nick; obviously used, but only hobby use. A young bloke somewhere in Ipswich bought it after I advertised it on Gumtree. I promptly forgot all about that machine.
Until last weekend, when a friend rings up and tells me that he's bought a used Carbatec Table Saw at a bargain price, but he having some problems with it. Seeing I'd owned that same model of saw before, he asked me if I'd have a look at it for him.
As soon as I locked eyes on my friend's new-to-him second hand table saw, I recognised that he'd bought my old faithful Carbatec Table Saw. It was easily recognisable by the Rockler Biesemier Style TableSaw Fence that I'd installed, and by the mods that I'd made to improve dust capture. It still looked to be in reasonable condition, so what was the problem that my friend was having with his new to him table saw ?
My friend demonstrated the problem by doing a rip cut on a 35mm thick piece of Blue Gum. The saw cut sloooowly, and the motor tended to stall if you tried to push the piece of wood even a little bit harder. So, on through some diagnostics to try and work out what was wrong:
Blade - a brand new Freud Combo Blade, which should be OK. So, we tried a CMT Rip blade just in case, and got the same result.
Arbour Bearings maybe - Open the cabinet. Gawd - the cabinet is nearly full of wood chips - the previous owner must have been using it without a dust collector. Clean the cabinet so we can find the motor and belt adjustments. Remove the belt. Spin the blade by hand to test for seized bearings. No problem. Checked the blade for side play. No problem.
At this point, we observed that the belt was very well worn, and needed replacement, but that wasn't the cause of the problem.
Must be the electric motor - crook capacitors, or maybe motor half burnt-out. Wrangled the motor out of the cabinet, and onto the work bench, and gave the motor a good clean. Was just about to start pulling the motor apart, when I had a look at the pulley on the motor shaft.
The motor pulley didn't look right. It was quite a bit bigger than I remembered, and the V-belt was sitting way down in the pulley's v-groove. It looked like the pulley was made for a much bigger belt. A closer look revealed that the pulley (about 6 inches diameter) had an ~1" hole which had been sleeved to make it fit the 5/8" motor shaft. So, the previous owner had changed the motor pulley for a larger one for some reason.
Well, that explained the reason for the saw cutting poorly, and stalling often. With the larger pulley on the motor, the blade would have been running faster under no load (although you couldn't tell by listening to it), but as soon as any cutting load was applied the blade it ran much slower that it should.
At that stage we didn't know for sure what diameter the original pulley had been, so a check with Carbatec in Brisbane revealed that it should have been a 4" pulley - but no sorry, Carbatec no longer stock parts for that old model saw, but you should be able to get a generic pulley to fit. Agreed.
At that point, my mate rang up the bloke that he'd bought the saw from to ask if he still had the original pulley.
And the bloke's response ...... and this is where the "Pretty Dumb" bit comes in...
"Yea, it's around here somewhere. But the pulley's no good. The belt kept slipping so I had to put a bigger pulley on to be able to get the belt tight enough, 'cause there wasn't enough adjustment to tighten the belt on the small pulley."
OK - my mate politely tells the bloke that he'll pop over and pick up the pulley, if that's OK. The bloke thought he was stupid wanting to put the old pulley back on the saw, but he gave my mate the pulley anyway.
We installed the old pulley, along with a new belt, and "bingo" - the saw is back to normal cutting performance,and at a bargain price - $200 for a 10" Table Saw in good condition, plus $7.50 for a new belt.
So, after all that, we still can't understand what possible logic had gone through that bloke's brain in order for him to arrive at the decision to put a larger pulley on the electric motor, because the belt was slipping ..... ???????
So we've decided that ----- Some Folks Can Be Pretty Dumb ....... !
RoyG
Until last weekend, when a friend rings up and tells me that he's bought a used Carbatec Table Saw at a bargain price, but he having some problems with it. Seeing I'd owned that same model of saw before, he asked me if I'd have a look at it for him.
As soon as I locked eyes on my friend's new-to-him second hand table saw, I recognised that he'd bought my old faithful Carbatec Table Saw. It was easily recognisable by the Rockler Biesemier Style TableSaw Fence that I'd installed, and by the mods that I'd made to improve dust capture. It still looked to be in reasonable condition, so what was the problem that my friend was having with his new to him table saw ?
My friend demonstrated the problem by doing a rip cut on a 35mm thick piece of Blue Gum. The saw cut sloooowly, and the motor tended to stall if you tried to push the piece of wood even a little bit harder. So, on through some diagnostics to try and work out what was wrong:
Blade - a brand new Freud Combo Blade, which should be OK. So, we tried a CMT Rip blade just in case, and got the same result.
Arbour Bearings maybe - Open the cabinet. Gawd - the cabinet is nearly full of wood chips - the previous owner must have been using it without a dust collector. Clean the cabinet so we can find the motor and belt adjustments. Remove the belt. Spin the blade by hand to test for seized bearings. No problem. Checked the blade for side play. No problem.
At this point, we observed that the belt was very well worn, and needed replacement, but that wasn't the cause of the problem.
Must be the electric motor - crook capacitors, or maybe motor half burnt-out. Wrangled the motor out of the cabinet, and onto the work bench, and gave the motor a good clean. Was just about to start pulling the motor apart, when I had a look at the pulley on the motor shaft.
The motor pulley didn't look right. It was quite a bit bigger than I remembered, and the V-belt was sitting way down in the pulley's v-groove. It looked like the pulley was made for a much bigger belt. A closer look revealed that the pulley (about 6 inches diameter) had an ~1" hole which had been sleeved to make it fit the 5/8" motor shaft. So, the previous owner had changed the motor pulley for a larger one for some reason.
Well, that explained the reason for the saw cutting poorly, and stalling often. With the larger pulley on the motor, the blade would have been running faster under no load (although you couldn't tell by listening to it), but as soon as any cutting load was applied the blade it ran much slower that it should.
At that stage we didn't know for sure what diameter the original pulley had been, so a check with Carbatec in Brisbane revealed that it should have been a 4" pulley - but no sorry, Carbatec no longer stock parts for that old model saw, but you should be able to get a generic pulley to fit. Agreed.
At that point, my mate rang up the bloke that he'd bought the saw from to ask if he still had the original pulley.
And the bloke's response ...... and this is where the "Pretty Dumb" bit comes in...
"Yea, it's around here somewhere. But the pulley's no good. The belt kept slipping so I had to put a bigger pulley on to be able to get the belt tight enough, 'cause there wasn't enough adjustment to tighten the belt on the small pulley."
OK - my mate politely tells the bloke that he'll pop over and pick up the pulley, if that's OK. The bloke thought he was stupid wanting to put the old pulley back on the saw, but he gave my mate the pulley anyway.
We installed the old pulley, along with a new belt, and "bingo" - the saw is back to normal cutting performance,and at a bargain price - $200 for a 10" Table Saw in good condition, plus $7.50 for a new belt.
So, after all that, we still can't understand what possible logic had gone through that bloke's brain in order for him to arrive at the decision to put a larger pulley on the electric motor, because the belt was slipping ..... ???????
So we've decided that ----- Some Folks Can Be Pretty Dumb ....... !
RoyG