thicknesser snipe

[Peter Sefton]

In my experience chain ganging end to end will solve most snipe problems. Even very robust thicknessers can suffer with snipe.

If the table is not rocking then the issue is usually down to pressure on the roller springs. To much pressure will push the timber and bed down (and very hard to stop even following all the useful suggestions above by others), not enough will not pull the timber through the machine.

I think I have an old machine maintenance handout somewhere, if you send me an email I will try and find it.
[email protected]

But my advice is keep your timber longer and cut the snipe off, I think you might go around in circles trying to improve your planer.

Cheers Peter

 

[Fitzroy]

Uneven pressure from the rollers, inadequate on the outfeed, would mean that there is the possibility of the board raising as it comes away from the infeed roller. This would also mean even by ganging the boards through you see snipe on the 'ganged' end. Do you get snipe on both the in end and out end of ganged boards?

I think it's still odd though as the outfeed roller only needs to hold the board on the table. If there was so little pressure I'd expect the board may not even be moved forwards correctly by the roller.

F.

 

[Noel]

Maybe there's a snake in it? : )

The table does not sag, the timber does not flex, the timber does not pivot, centre of gravity has as much to do with it as cheese.

Bob, understand how the thing works, always a good start. Somebody posted Mathias Wendell's video. Everything is in there. The cutter head rocks, swings, moves, twitches, jumps, ticks, moves and squiggles when only one roller is engaged, fact of life. You have no head lock on it, so it is very slightly worse than those with a lock. That level of machinery has limitations, don't expect too much of it.
I don't think you have a problem, as nearly everybody has said, snipe happens. Just get used to it.

Good advice:

In my experience chain ganging end to end will solve most snipe problems. Even very robust thicknessers can suffer with snipe.
But my advice is keep your timber longer and cut the snipe off, I think you might go around in circles trying to improve your planer.

Cheers Peter

 

[twodoctors]

I read a bit on part one, and didn't comment because I'm very new to wood working and planer/thicknesser.

I bought a SIP machine recently and also had snipe but only at the front. Common problem as you have found reading other posts. I found that taking a little bit off at a time helps, as the difference in height of pre- and post roller/bed would also minimise the amount of snipe to minimal. Takes a few more passes but at least no snipe. I do about 1/4 or 1/3 turn per pass. You have a better machine than mine so hopefully it's not a mechanical problem.

Good luck.

 

[Jacob]

....
I don't think you have a problem, as nearly everybody has said, snipe happens. Just get used to it....

And plane it off by hand. It doesn't even look very severe in the photo so couple of minutes should do it.
It's essential to be able to apply a hand plane finish every now and then as snipe and other machine blemishes will happen very often.

If you have snipe already on the underside it is likely to be reflected on the top as the underside is effectively slightly convex and will tilt as it goes under the pressure of one roller rather than two.
If it isn't flat on the table side it probably won't come out flat on the top. This would account for all your problems.

PS in fact these table-top thicknessers are not much use unless you flatten your face and edge first. Happens with bigger machines too - I did some 4 metre 100x100mm newel posts impossible to flatten over the top (too big to manhandle) so had to do face and edge by hand - then a doddle to thickness back face and back edge - even with a little machine like yours if its fastened down well and you have feed rollers etc.

 

[Jacob]

I've been stirring this around in my little brain with little joy. Getting snipe on both ends of chain-fed stock would imply to me that the piece exiting has to be tilting down (to raise the tail end up towards the cutter) after passing the infeed roller. Similarly, the next piece in the chain has to be tilting slightly upwards until it hits the outfeed roller.

My first thought would be the contiboard tray is ever so slightly bowing up towards the block. Not doubting you sunnybob when you say it's flat though. I'd still try chain ganging stock through without the board and see what happens if only to eliminate the tray. Apologies if you've done that already!

Another thought would be to try, instead of putting stock through end on end, to put them through in a staggered pattern:



The idea being both rollers are always in contact with one piece at all times. It won't stop snipe on the first and last piece though.

Everyone loves a good mystery!

Often fails as the pressure on one side may be enough to take the pressure off the other and it will flop about and get a rough cut. Worse if they are a gnats different in thickness to start with.

 

[sunnybob]

I'm taking minimal cuts, less than a quarter turn, still snipe both ends. Planing on one side only, bottom side left as is.

I've just run a piece through with all the covers off and the outfeed roller does push the piece out but there is a noticable slackening of pressure once the wood leaves the cutting head.
But that infeed roller pressure seems very excessive to me. With a board in there and power off, theres no way you can get the board out without using a club hammer and drift.
The extended base I have made is flat and square to the base of the machine, and on the sized pieces I am trialling with there is no relevance to it. I never use boards longer than 2 metres through it, and rarely even at that length.

After planing the piece i turned the power off and pushed it back through and it stopped at the feed roller because the roller is a good 5 mm below the top of the wood.

Each roller has a spring at each end, and according to the parts diagram, there are two different springs used, strangely the 2 types are alternated on the rollers. So the drive of one has a different part number spring to the drive of the other. therefore the free running ends have different springs to each drive end.

Cant find any spec on those springs yet. I just may take it all apart and see about reducing the pressure on that roller as I have nothing to lose.

 

[Jacob]

I'm taking minimal cuts, less than a quarter turn, still snipe both ends. Planing on one side only, bottom side left as is........

See above posts. If the bottom side isn't perfectly flat the top won't be either.

 

[Nelsun]

Another thought would be to try, instead of putting stock through end on end, to put them through in a staggered pattern:



The idea being both rollers are always in contact with one piece at all times. It won't stop snipe on the first and last piece though.

Everyone loves a good mystery!

Often fails as the pressure on one side may be enough to take the pressure off the other and it will flop about and get a rough cut. Worse if they are a gnats different in thickness to start with.

Never tried it myself but that makes sense. Aw well. I'll stick to counting on snipe and assigning it to the burn pile.

 

[Peter Sefton]

The feed rollers being 5mm lower than the cut thickness sounds excessive.

All planers will be different but I have just checked my Hammer and both the infeed and outfeed rollers appear to be around 1.1mm lower than the timbers finished thickness and our snipe is usually around one tenth of a mm.

Cheers Peter

 

[sunnybob]

Peter, please see the other thread thicknesser woes part 2.

 

[sunnybob]

I've just spent a very interesting time with the thicknesser in bits.

Taking the feed roller out I discovered significant burning discolouration one of the bearing blocks. the spacer behind the chain wheel was binding on the block. i eased the spacer, re greased both blocks, and inserted 2 mm shims under both bearing blocks to raise the roller.

Put it all back and the test piece shows snipe significantly reduced. Not gone, but must be only half the depth it was, and the rear snipe even less.

Before, the snipe was so bad that looking at the wood sideways it looked as though the wood had been rebated. Now a sideways view does show snipe at all, its only visible full on.
I can cope with what I have now, its so slight that sanding with a long block will remove it.

I've had enough for one day, but before reassembling I just might put another 1 mm shim in there.

Oh, and the odd springs... Theyre not odd, just a bad parts diagram. I checked length, wire thickness and coil numbers, and they are identical even though the book shows different part numbers.

time for tiffin.

 

[sunnybob]

This is really bizarre, this site wont let me get to my other thread labelled woes part 2.
I just had to post and delete several times but still cant post the above reply from me, into the part 2 thread. Ap[ologies for any confusion caused here, its NOT me!

 

[MikeK]

This is really bizarre, this site wont let me get to my other thread labelled woes part 2.
I just had to post and delete several times but still cant post the above reply from me, into the part 2 thread. Ap[ologies for any confusion caused here, its NOT me!

It appears the Woes Part 2 thread has been combined with this thread. The Woes 2 posts have been inserted chronologically with the posts in this thread. If you look at the subject lines of some posts, you will see "Thicknesser woes part two".

 

[sunnybob]

how odd

 

[Jacob]

how odd

It's a mod edit. If you read back you'll see a note.
If you read back you will also see my suggestion - that your probs might be caused by the workpieces not being flat (already sniped?) on the underside. This is a common problem with thicknessers.

 

[sunnybob]

This why I started the second thread. By the time a thread gets to 3 pages people start losing the will to live and miss whats already been said.

Jacob (jacob?) the wood does NOT have snipe on the underside.

Yes, I WAS getting snipe on all short pieces gang fed.

The snipe is now reduced by at least a half, maybe 2/3rds, and its down to manageable proportions now.

I may compress the infeed roller even further tomorrow, if so I will report back.

 

[Jacob]

...
Jacob (jacob?) the wood does NOT have snipe on the underside.....

But is it perfectly flat? If so how did you get it flat?
If it's the slightest bit convex or twisted - even if you can barely see it, you will have problems.

 

[sunnybob]

Jacob, flat isnt (wasnt) the issue.
Snipe was the be all and end all of my questions and complaints.

 

[Peter Sefton]

Peter, please see the other thread thicknesser woes part 2.

That's five minuets of my life I will never get back :lol: