Planer fence

[dog_party]

Hi - I found this forum very useful when I was buying my planer thicknesser (Metabo hc260), so I've registered here since I have a question about it.

It works great when I'm just planning flat, but I just can't get it to give me a precise 90° angle on the second face if the workpiece. I'd initially assumed that the fence was the problem, and it was indeed a little cupped; so I spent a while working on it and have now ground it flat enough that you can't get a 0.02mm feeler gauge between it and a straight edge. But even with it set up at 90° to the table with a machinist's square (and checked with a second square, as I was getting paranoid at this point), it still gives me a slightly obtuse angle on every piece! Frankly, it's driving me insane- if I compensate by setting up the fence a little out of true, I can run a piece over and get a square edge, but that's just not a way I want to do things. I want to be able to set it up precisely at 90 and have that be the angle it gives me.

I've never used a planer thicknesser before, so I'm not sure whether theres something I'm missing- is there anything else that needs truing up somewhere? Or am I just expecting too high a degree of accuracy- is it the case that this just isn't the tool to give me dead accurate square angles, and I should instead be flattening one face then take the piece over to square the edge on the tablesaw?

Thanks in advance for any advice!

 

[Spectric]

If you run one piece through face up and the other face down then in theory even if it is slightly out of square they will be ok.

 

[dog_party]

Thanks for replying- do you mean as a way of getting multiple pieces to sit flat when butted up against each other? That would work great for panels etc, but there are also lots of joints where I'd like it to be dead square.

 

[recipio]

Assuming the fence is adjustable you should be able to get a square edge. Be careful of sawdust at the base of the fence and keep constant pressure against the fence - two rubber faced push pads help. I set mine with a good torch shining behind the square - It's amazing how hard it can be to get an accurate reading.

 

[Fitzroy]

If your planer knives a not parallel to the bed it will cause issues, although that should also cause surfacing issues, but worth checking.

I find I have to set up the fence square just past the cutter block and ensure that is where I am applying the pressure on the board.

You can easily apply a great deal of pressure on a fence, if it is not sturdy you can push it out of square, you could be doing this and then having to set it less than square to compensate.

 

[Orraloon]

The alloy fences are not as robust as those with cast iron so like Fitzroy says perhaps you are flexing the fence as you push against it. Set it square to the table and practice a bit with some scrap bits of pine.
Regards
John

 

[pgrbff]

I have a 12" SCM. The fence is Aluminium and only supported at one end. My fence is also not flat. As it isn't flat I just set it up so it gives me an edge at 90 degrees. If the fence flexes at its end, nearer the cutter head, don't push too hard against it.
To my mind it isn't that different to using a hand plane, it isn't automatic, it still takes skill and constant checking to get right.

 

[Fergie 307]

I think Fitzroy has a good point. You don't say how far off your angle is. But if you are happy that the fence is at 90° to the table, and isn't moving, then the only real explanation is that the blades aren't parallel with the table. If they are only slightly out you might not notice it when surfacing. I would certainly check that before going any further. Not familiar with the machine but it could either be the mounting of the blades themselves, or that the whole cutter block is a little out. How does it perform in thickness mode, does it cut parallel? If it leaves a board slightly thicker one side than the other that would also suggest the blades aren't aligned correctly.

 

[Jester129]

Run a flat piece of wood (say 150mm wide) over the table several times on the one side, then turn it end over end and do the same on the other side the same amount of passes. Now measure each side with a digital vernier. If they are different thicknesses the issue is with the blades not set correctly or the blade holder is not 90 degrees to the fence.

 

[dog_party]

Run a flat piece of wood (say 150mm wide) over the table several times on the one side, then turn it end over end and do the same on the other side the same amount of passes. Now measure each side with a digital vernier. If they are different thicknesses the issue is with the blades not set correctly or the blade holder is not 90 degrees to the fence.

I just tried this and it went exactly as you described - turned out thinner on one side than the other. I'll see what I can do with the blades and blade holder.

 

[dog_party]

I just tried this and it went exactly as you described - turned out thinner on one side than the other. I'll see what I can do with the blades and blade holder.

Well after a bit of faff I've got it producing the angles I'm after-- needed to adjust the blade angle on one side of the block as it wasn't parallel to the table, and remove the other blade and flip it over over as it had a pronounced bow shape along one edge and so wouldn't go parallel no matter how much I messed about with it. Took a while but I found a New Brit Workshop video on YouTube that went through the steps in a clear way. It's running great now.

Thanks everyone for your advice here- there's no way I'd have worked this out in my own! I'd just assumed it would all come dead square from the manufacturer, but in reflection I've no idea why I thought that- nothing ever does.