Snipe, what am I doing wrong?

[brianc]

Hi all,
I'm getting quite a bit of snipe on both ends of an old oak (?) stair tread despite using a long plank for a base.

It's a Metabo HC 260 and the base plank is approx. 5' long (1500mm). I don't think the plank is moving but it is possible, should this be clamped to the cast iron lifting bed maybe?

The wood I'm trying to clean up is shown in the photos, it started off at 35mm thick but is already down to 28mm due to cupping and my attempts to get rid of the snipe!

Any advice would be great, many thanks...
Brian.

 

[Yojevol]

Have you tried it without the base plank?
Brian

 

[brianc]

Have you tried it without the base plank?
Brian

Yes, I did a bit of work last week and had the same issue without the plank

 

[recipio]

I used to get snipe with my Scheppach if the planer blades were set too high. Set them so they just ' touch ' a batten on the outfeed table.

 

[Jones]

A planer with long tables will help straighten a plank but a thicknesses has much shorter tables and the timber is held down by the rollers. I think using a long plank to extend the thicknesser bed will not bring any benefits and may cause problems . Snipe can be caused if you don't support the plank as it comes out or may be by incorrect feed roller pressure. The rollers are spring loaded and can be adjusted. Waxing the bed so it feeds readily may also help.

 

[sometimewoodworker]

Hi all,
I'm getting quite a bit of snipe on both ends of an old oak (?) stair tread despite using a long plank for a base.

It's a Metabo HC 260 and the base plank is approx. 5' long (1500mm). I don't think the plank is moving but it is possible, should this be clamped to the cast iron lifting bed maybe?

The wood I'm trying to clean up is shown in the photos, it started off at 35mm thick but is already down to 28mm due to cupping and my attempts to get rid of the snipe!

Any advice would be great, many thanks...
Brian.

There are quite a few things you can do but first you need to set both the knives and the platters to the correct hight, there are many videos showing this.

Next you need to understand that snipe is often caused by the pressure rollers, there are a couple of ways to avoid this, one is to always use longer boards so you can cut the snipe off, one of the other ways is to completely avoid the problem of one of the rollers dropping off the board by always having a second board following the project board this stops the pressure rollers dropping off.

A common mistake is to think that you should cut your project to length before thicknessing, you will often need a piece that is the identical thickness to one of your project pieces, so cut to length after thicknessing.

I have virtually eliminated snipe in my projects as it is now only on trailing scrap pieces.

 

[brianc]

Just watched this Peter Parfitt video on how to set the blades. It now looks like I also need to check the beds as well as the rollers, which one do I need to do first or does it not matter?

When feeding the thicknesser, it's a tight fit to get underneath the first roller. However, the cutter barely touches if I lower the bed to make the first roller easier to feed into...

 

[rogxwhit]

When you say cupping I hope you're removing that on the top tables with the cup facing down?

By paying attention to the work (listening, watching and feeling) as it feeds through you should notice when the sniping is happening, which'll help you address it. Noting that the snipe is inset from the end at a certain distance points to it being related to when one or other of the rollers grabs or releases the stock. This suggests to me that the problem is that you're not supporting the work by hand as it feeds in and feeds out. Because the work's cantilevered beyond the table it needs a bit of light assistance to balance it in line. You'll get a lot of information through your fingertips whilst doing that and sense what to do.

For the lengths shown I wouldn't bother with the intermediary false bed - it'll just complicate the issue. Pay more attention to what I just said above.

 

[Fitzroy]

Could be to do with two things, one as the piece come off the feed roller the head is moving due to play, feed a piece after the main workpiece would help this.


With long boards as the piece comes off the feed roller the long end is dropping lift the shortens into the cutter head. Technique I use to avoid this is to really concentrate on holding the long end level as it exits, or even try to lift it fractionallly.

 

[rogxwhit]

When feeding the thicknesser, it's a tight fit to get underneath the first roller. However, the cutter barely touches if I lower the bed to make the first roller easier to feed into...

Everything on an over-under is interdependent, so to set it up a bit of logic and trial and error is wanted. The above suggests to me that the knives aren't projecting enough. So set them a bit further out. It shouldn't take much - half a mm to start? A mm if that proves not enough. Make the projection even across the cutterblock, but check that it's also parallel to the thickness table otherwise you'll have another problem. That should fix the apparent disparity you've got between the cutting circle height & the feed roller height.

Another variable is the feed roller pressure, which can be adjusted.

After getting all that working nicely, you'll have to reset the outfeed table to the new knife projection. The last op is to align the infeed table to the outfeed, crossways and along. A metre straightedge is a handy thing to have.

The whole thing could take some time & drive you nuts, but be patient & determined.

 

[brianc]

Thanks for the advice so far, very helpful!

Both blades looked fine when using the little height gauge but there was at least 10mm movement when 'rolling' a batten along the infeed table. I set the first blade to about 7mm across the cutter width then found the second blade was also 7mm so I left that one alone.

Yes I removed the cup using the planer before placing the planed face on the thicknesser bed. Once the other face was done, I flipped the piece over to thickness the pre-planed surface although I'm not convinced that was necessary.

The next step I'll try will be to release the pressure on the infeed roller, as it feels even tighter now that I have adjusted one of the blades. I'm off to YouTube for some more visual instruction now...

 

[MARK.B.]

When you make any adjustments and until you get things just right,make a note of what you do adjust and by how much,then if one setting does not work you can put things back as they were before having another try.The problem with adjusting this and that willy nilly is that it can sometimes make things a whole lot worse than when you first started,don't rely on memory alone as often what we remember may differ from what it actually was.

 

[MikeJhn]

Set the blades at the height of the outfeed table, not higher as most do, never had snipe of any kind using a piece of plate glass to set the blades.

 

[MorrisWoodman12]

With my HC260 I particularly get snipe if I don't keep the board level as it enters and exits the thicknesser. I would have hoped your long support board would have cured the problem but it would also need to be supported as well so it doesn't rock as the other enters/exits the thicknesser.
I can't add any advice other than that unfortunately but would ask you to post what solution you arrive at for the rest of us to learn.
Thanks
Martin

 

[rogxwhit]

With my HC260 I particularly get snipe if I don't keep the board level as it enters and exits the thicknesser.

This applies to any thicknesser regardless of make or model. Though the lighter the machine and the shorter its thicknessing bed the more crucial it becomes.

 

[charles79130]

I’ve tried pretty much everything on my SIP even purchased blade setting jigs but still I get snipe
good luck

 

[rogxwhit]

You have to distinguish between snipe when surfacing and snipe when thicknessing. The first is attendant on top table & knife adjustments, the second is all to do with workpiece control.

 

[deema]

Snipe is to be expected on all PT’s, it’s the nature of the beast. As the board passes through the thicknesser, you can end up with snipe at the start and end of the board. Initially the board is only pinned down to the bed by the first feed roller roller, it its a long board or the operator a bit careless the board can tilt up into the cutter before it passes by the cutter and is caught and held down by the second outfeed roller. At the end of the board, the board passes by the infeed roller and is no longer held down, and again can tip up into the cutter.

The way to minimise it is to have as long a bed as possible, careful feeding and supporting the board on its exit. Most usually account for it and allow say 4” 100mm of extra stuff in case of snipe. Often snipe can be lost in tenons.

 

[Stuart Moffat]

I also have the hc260.
I agree with rogexwhit also. Once the machine is set up right, control of the workpiece in and out is crucial. Practice and you will get better. It’s rare I suffer nowadays. I do use a pair of rollers for very long stuff, say over 2M, but it still needs controlling at the appropriate moment.

 

[rogxwhit]

I do use a pair of rollers for very long stuff, say over 2M

Trouble with outboard rollers (for thicknessing) is providing the right alignment, both longitudinal and lateral (not every floor is flat!). Hand support is more flexible and sensitive. Yes, even on long heavy pieces. You may be near the extremity of the workpiece but you are feeling via that workpiece for the contact with the bed of the machine and making live adjustment to your support. You are conspiring with the bed and the rollers, with your attention channelled through your fingertips along the work. Whilst the work passing through is around the mid point it's fairly balanced and that's when you walk round to take up a similar duty at the outfeed end.