planer snipe

[marcros]

I seem to be getting quite bad snipe on my planer since changing blades. It didnt happen before, so it suggests bad setup to me.

I have bought one of the oneway multi gauges, which should arrive tomorrow. That should eliminate having to try and set them using the drag method, and should give consistent results and a known measurement.

Assuming that cutter block is parallel to the outfeed table, what height above the outfeed table should the blades be?

 

[katellwood]

assuming your outfeed table is height adjustable wind down the outfeed table then take a small cut approx. 2" - 3" long from the infeed table, following this adjust the outfeed table up to the cut. with fine adjustments you should be able to eliminate snipe completely

If your outfeed table is fixed (sedgwick et al) then to set the blades level with the outfeed glue a magnet into the end of two straight bits of timber, set the magnets coplanar with the straight sides of timber. Weigh down the timbers onto the outfeed table at each end of the cutter block with the magnets over where the blades should mount in the block. by carefully tightening the clamping nuts of the blades and keeping the cutting edge in contact with the magnets you should get the top of the blade at the top of its arc in line with the outfeed table at each end of the block.

Also bear in mind that if your machine is a planer thicknesser the cutters will need to be parallel to the thicknesser bed and the measure scale may need adjusting for accurate work

Hope this helps

 

[marcros]

It is an axi stand alone planer. I think that the outfeed is adjustable.

I have the gauge on its way, and would be happier with a measurement. From what you are saying though, perfection is absolute zero (= flush with) from the outfeed table, however it is achieved?

 

[Jacob]

It is an axi stand alone planer. I think that the outfeed is adjustable.

I have the gauge on its way, and would be happier with a measurement. From what you are saying though, perfection is absolute zero (= flush with) from the outfeed table, however it is achieved?

Well no. If you had it dead flush the slightest bit of dust, variable pressure or vibration would lift the workpiece (it couldn't lower it) and reduce the cut. This would be progressive. The cutters need to protrude very, very slightly from the plane of the two tables set in line. In other words snipe is almost unavoidable (some of the time) - it's just a question of minimising it.
The trial and error drag a straight edge setting method is as good as any.

 

[marcros]

that is what i was thinking based on previous threads. so how much is very very slightly- a thou? 4 thou? 10 thou?

 

[Chrispy]

that is what i was thinking based on previous threads. so how much is very very slightly- a thou? 4 thou? 10 thou?

Well it's a little bit more than not quite enough and a bit less than just a little to much :lol:

 

[katellwood]

Absolute zero, no, as Jacob says the outfeed table slightly below. the main reasons I can see is that a planer does not cut flat it takes radial cuts relating to the number of blades, the diameter of the block and the feed speed of the timber

like this



therefore for no snipe the outfeed table should be set to this height



however this demonstrates an exact science, I would always set the outfeed slightly lower as if its too high it will slowly lift the material off the infeed table and will not produce a straight/flat planed surface which is what we are trying to produce. In addition snipe is only in the last couple of inches and is usually trimmed away anyway

open to discussion

 

[marcros]

this was an issue because i was very tight on length of wood, although luckily not critical on the width remaining.

 

[custard]

Assuming that cutter block is parallel to the outfeed table, what height above the outfeed table should the blades be?

The manufacturer's recommendation for my planer is that the knives should be 0.001-0.002" above the outfeed table, furthermore there should be no more than 0.002" variation between the knife heights either along the cutter block or from knife to knife.

My machine is within these specifications and I have virtually no snipe, either when planing or when thicknessing. By the way, I also use the Oneway gauge for setting the planer (and much else besides) it's an excellent tool.

 

[longinthetooth]

A gauge is completely unecessary to accurately set planer knives.

 

[RogerP]

I lay a single sheet of ordinary printer paper on the out-feed table then place on it a steel straight-edge on its edge and extending over the cutter-block. Then simply bring up the knives to just kiss the ruler. Do both ends of each knife .

Jig, gauges etc are an unnecessary expense - good for the sellers though

 

[No skills]

I lay a single sheet of ordinary printer paper on the out-feed table then place on it a steel straight-edge on its edge and extending over the cutter-block. Then simply bring up the knives to just kiss the ruler. Do both ends of each knife .

Jig, gauges etc are an unnecessary expense - good for the sellers though

That's a good one, will try to remember that for the future.

 

[custard]

A gauge is completely unecessary to accurately set planer knives.

With thirty years experience I know how to set planer knives using a scrap of wood, I've done it hundreds of times. But I can do the job faster, more consistently, and I believe more accurately with a Oneway Gauge.

 

[marcros]

I can't get the consistency. As a result I dread changing them, put it off for too long and try to do jobs with dull knives. I think that a measuring device will help here. We will see when the one way arrives- I haven't seen a negative review.

 

[custard]

I can't get the consistency. As a result I dread changing them, put it off for too long and try to do jobs with dull knives.

I don't think you're alone Marcros. In most of the workshops that I've seen, the planer knives (and the bandsaw blade) are usually long overdue for a sharpen.

There's one cabinet maker I know who always used to bang on about the right and wrong way to do everything, but he was actually one of the worst offenders when it came to maintaining his own equipment, I'd watch him have to heave like a rugby forward to get a board across his planer because the knives were so dull!

 

[Steve Maskery]

KW - That is one of the best diagrams of how a planer cuts that I have seen.

The things about jigs is that, yes, you can do the same job by hand. But jigs, whether home-made or off the shelf just make the job easier. Maybe faster. Maybe safer. More consistent maybe. But generally better, so it may well be a good investment. And if it is so good that you change your blades when you think they need it, rather than waiting until there is no doubt, then you will get better results generally, and have a more pleasurable time in the workshop than if you are fighting the machine all the time.

For another take on snipe: http://www.youtube.com/watch?v=mHfjSatKITQ

Cheers
Steve

 

[Giff]

I think it has been mentioned before but disposable turn blades only need setting once and then replaced ( or turned over first as they have two sides) when dull. The system uses spacers and holders and I think they are available for quite a few machines. What was a nightmare job is a dodle. Cutting Solutions do them as a kit. http://www.cutting-solutions.co.uk Geoff

 

[katellwood]

KW - That is one of the best diagrams of how a planer cuts that I have seen.

Thanks Steve, as you may see I've got a problem with sketchup. When I try to export as a jpeg it does not show the infills just the lines. they looked better when they were filled. I will repost using the snipping tool which may look better

 

[katellwood]

Here you go

 

[marcros]

Here you go

Does this suggest that no matter how good the setup, you will never get a glue up surfance straight from the planer because on some magnification or other the surface cannot be fully flat?