Eric the Viking
Nordic Pine
- Joined
- Dec 10, 2020
- Messages
- 668
- Reaction score
- 128
My 439 is old and ought to be worn out. It has some annoyances, such as steamrolling chips into the top surface when thicknessing, and, until recently, really horrid snipe on the thicknesser. But it still keeps going heroically.
The snipe was worse with short stock, which is extra annoying, as shorter pieces are usually cut to size...
... but I had a lightbulb moment recently, and Rafe and I managed to do the necessary, and fix the snipe, apparently completely.
This last week-end I had a session making up crown molding from AWO, and when cleaning the machine afterwards, I thought I should take a look, and yes, it was setting up to start creating snipe all over again -- glad I checked.
So what was the cause? Sawdust!
There are the usual two rollers for the thicknesser, infeed and outfeed, either side of the cutter block. Like a train carriage bogey, they have strong springs above the 'axles' each side, and the bounce up and down in oval slots, so they accommodate a change in height as the wood passes through. Obviously, there's one each end of each roller - four altogether.
It turns out these ovals are the ideal places for wood chips to collect, especially under the infeed roller, as it's right in the line of fire from the planer knives. The stock is grabbed and pulled in by the roller, lifting up and leaving a handy space under the roller's bearing sleeve, which the cutter block then fills with as much rubbish as it can manage, before the roller drops again at the end of the pass, and squishes it all in there tightly. Those 'suspension' springs are really strong!
On the second pass, the process repeats, but each time the rollers don't drop quite as far down as they did before, because of the chip build-up where it shouldn't be. Every pass compacts the chips further, so a pretty solid mass builds up in there.
How does this cause snipe? Near the end of the workpiece, the infeed roller quits first, obviously, but the outfeed roller can't push the stock down quite enough on the platen (bed) of the thicknesser (chips in the way). So the back end of the stock lifts slightly, into the cutter block, giving the snipe I hate.
All I have to do, is keep those oval sleeves clean of chips, so the rollers can drop down enough, and it runs sweetly. No snipe at all.
How do I do this? A small bit of small-gauge fencing wire with a small hook bent on the end. And a narrow wooden block, slightly shorter than the thicknesser's height capacity, to push the roller up out of the way, so I can get in there to scrape out the accumulated muck. It works well.
Having done this very recently (with Rafe's help), I was surprised how much had accumulated in there in just one session thicknessing relatively small bits of AWO.
I was making cornice moulding, and using the moulded face as my reference, so that ran on the thicknesser bed, with a 45 bevel on either edge of the piece (I was thicknessing the back of the moulding and I"d already done the bevels that will be top and back of a 45 degree cornice). I suspect those bevels caused some sideways bounce of chips, more than normal squared stock. Even so, a lot built up in a short time.
Cleaning those oval slots will now be part of the routine, with one alteration: I've just been using offcuts pushing up in the middle of the roller. But that also means pushing down into the bed of the thicknesser. This isn't good, as the Kity models have non-ferrous beds and tables, and a point pressure like that risks distorting the bed. So I'll make up a T-shaped block (probably a wooden plate with a tall thin block in its centre) to spread the load on the thicknesser bed. Otherwise, it's a winner!
I know you lot demand pictures - they'll have to wait until I have time. I thought it might help someone else, so worth the write-up. If you have a similar over-under machine, with fixed planer tables, it might be worth checking to see if you have the same issue building up.
The snipe was worse with short stock, which is extra annoying, as shorter pieces are usually cut to size...
... but I had a lightbulb moment recently, and Rafe and I managed to do the necessary, and fix the snipe, apparently completely.
This last week-end I had a session making up crown molding from AWO, and when cleaning the machine afterwards, I thought I should take a look, and yes, it was setting up to start creating snipe all over again -- glad I checked.
So what was the cause? Sawdust!
There are the usual two rollers for the thicknesser, infeed and outfeed, either side of the cutter block. Like a train carriage bogey, they have strong springs above the 'axles' each side, and the bounce up and down in oval slots, so they accommodate a change in height as the wood passes through. Obviously, there's one each end of each roller - four altogether.
It turns out these ovals are the ideal places for wood chips to collect, especially under the infeed roller, as it's right in the line of fire from the planer knives. The stock is grabbed and pulled in by the roller, lifting up and leaving a handy space under the roller's bearing sleeve, which the cutter block then fills with as much rubbish as it can manage, before the roller drops again at the end of the pass, and squishes it all in there tightly. Those 'suspension' springs are really strong!
On the second pass, the process repeats, but each time the rollers don't drop quite as far down as they did before, because of the chip build-up where it shouldn't be. Every pass compacts the chips further, so a pretty solid mass builds up in there.
How does this cause snipe? Near the end of the workpiece, the infeed roller quits first, obviously, but the outfeed roller can't push the stock down quite enough on the platen (bed) of the thicknesser (chips in the way). So the back end of the stock lifts slightly, into the cutter block, giving the snipe I hate.
All I have to do, is keep those oval sleeves clean of chips, so the rollers can drop down enough, and it runs sweetly. No snipe at all.
How do I do this? A small bit of small-gauge fencing wire with a small hook bent on the end. And a narrow wooden block, slightly shorter than the thicknesser's height capacity, to push the roller up out of the way, so I can get in there to scrape out the accumulated muck. It works well.
Having done this very recently (with Rafe's help), I was surprised how much had accumulated in there in just one session thicknessing relatively small bits of AWO.
I was making cornice moulding, and using the moulded face as my reference, so that ran on the thicknesser bed, with a 45 bevel on either edge of the piece (I was thicknessing the back of the moulding and I"d already done the bevels that will be top and back of a 45 degree cornice). I suspect those bevels caused some sideways bounce of chips, more than normal squared stock. Even so, a lot built up in a short time.
Cleaning those oval slots will now be part of the routine, with one alteration: I've just been using offcuts pushing up in the middle of the roller. But that also means pushing down into the bed of the thicknesser. This isn't good, as the Kity models have non-ferrous beds and tables, and a point pressure like that risks distorting the bed. So I'll make up a T-shaped block (probably a wooden plate with a tall thin block in its centre) to spread the load on the thicknesser bed. Otherwise, it's a winner!
I know you lot demand pictures - they'll have to wait until I have time. I thought it might help someone else, so worth the write-up. If you have a similar over-under machine, with fixed planer tables, it might be worth checking to see if you have the same issue building up.
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