Planer Technique or Setup?

[wcndave]

I've been planing some fairly cupped 34mm Maple, and was doing ok until one board whilst being edge jointed became tapered without ever removing material from the back end. I was pressing down lightly in the middle of the board. With a straight edge I can see the edge is slightly concave.

I then checked my tables (Scheppach HMS2600ci), and they were not co-planer.

I fettled the table, however 1) it is amazingly hard to level / adjust the tables, as there is no way to hold them whilst adjusting, and 2) I could not get both sides flat at the same time. If the fence side was flat (I tested by trying to get a 0.05 feeler gauge under the infeed and outfeed at both the end and the mouth), then the rear near side infeed was low. If I raised that, then the mouth edge of the fence side was low.

So I got them as close as I could, with 0.15 feeler gauge able to get under one corner of the straight edge of the infeed table.

I then reset the blades, however when the drag test was 4mm on the edges, there was no drag at all once I got only 2cm from the edge...

The blades have been recently sharpened and are straight when placed together on glass with white paper underneath.

I ran a few pieces over, and the leading edge of the board with the pressure gets thinner and thinner whilst the trailing edge doesn't and one trailing corner never gets processed.

I tried cup side down (unhappy smile), with a wobbly board, where with pressure near front the rear corner was 4mm off a level surface, and it still took a decent cut off that "raised" trailing edge...

Is it more likely to be the machine setup, or the technique?

I never seemed to have this problem until I "improved" the setup of the table - however I didn't have so much cupped stock before.

Any thoughts?

 

[RobinBHM]

Fade out on a surface planer is difficult to diagnose and the cause could be set up and/or technique.

I would be tempted to do some test pieces, using flat boards. If you have digital calipers, boards narrower than the max opening can be edged then the width checked at the front and rear of the board. Testing can be done at both sides of the blades, provided your fence slides across full width.

It sounds like your tables are pretty good perhaps very slightly twisted.

Cupped boards can be tricky to plane, as sods law dictates they often seem to be bowed the wrong way!

Best of luck :lol:

 

[deema]

If I recall correctly the order planners suggest that the beds should be within 0.2 overall, so you should be OK. However if you work the math, for the drag test the blades will be circa 0.2 above the table height for about 0.5mm of drag. So, the test you over formed would agree with your flatness estimate. I would raise the blades until you get about 0.3 drag at the lowest point on the blades, hopefully you will see about 0.8 at the heigext point on the blade. Not too much to worry about apart from a little step at the end of the cut.

The usual cause for a tapered board is that the blades are lower than the outfeed table, if you now try with the blades raised with good technique you should be Ok.

Try to get a cut depth slightly more than the amount of cup. Press down on the board only on the outfeed table. If the cup is too much, make sure you press down only on the leading edge when you have passed it over the cutter on the outfeed table. Do not press down on the wood that is not touching the outfeed table - you can tell where this is as the cutter stops cutting. It will start cutting as you continue to feed. Do not put any pressure downwards on the infeed table

 

[wcndave]

Thanks both.glad to know my tolerances are ok. I put the blades higher and if I keep weight at front avoid snipe. Any pressure at back I get quite a bit.

I still have some wobble on a flat surface however it's nothing the joinery won't remove. I have 1mm gap between two corners. The edging is still not really square despite a square fence, but I shall rip to final width on table saw which will square it up.

Feeling much better about it today!

Sent from my GT-I9100 using Tapatalk

 

[deema]

If the edge is not square your setup of the tables is not correct. It's a common problem when resetting the infeed table.

The first step is to get a clock and place it on the infeed table and with a blade in the block, use it as a guide to clock the table to the block. Clock on the block itself and not the blade, you use the blade to ensure your at the same point I. The block as you measure across its length. I'm certain you will find that the infeed table is not parallel to the block. Align the edge of the infeed table to the block. Now clock the front edge of the outfeed table to the edge of the infeed table next to the block, get these aligned. Now with a straight edge align the outer edge of the outfeed table to the outer edge of the infeed table using feeler gauges. You may find you have run out of adjustment so have to start again. Once you have set the tables, just check all positions again, the tweaks will have moved something. It's a little time consuming but with patience you will get it all aligned. Once done, check it every so often. Depening on the machine it will move over time, especially if you are moving the machine regularly.

 

[wcndave]

I am afraid you have completely lost me...

..use it as a guide to clock the table to the block...

Reading on you mention adjusting outfeed, and I think you're talking about the cutter head block not being aligned?

On my table these are fixed as far as I can tell and you can only adjust the infeed. At least that's how it's intended and how Alan (I think) from NMA describes it in his documents.

As I know my blades are up more at edges than centre I can always try with the fence set to the middle of the table, that might work better.

 

[deema]

Sorry if it was a little confusing.

When adjusting the infeed table, it's very easy to adjust it such that the front edge which is next to the cutter block is moved out of parallel with the cutter head. The cutter head will be fixed and secured in bearings and as you state and is not adjustable. Take a clock gauge, or anything that you can accurately measure the height of the infeed table form the cutter block. As the cutter block is circular, it's difficult to have a reference point to make the measurements along as you check the two outside edges and the middle. I use the blade to act as a reference. I.e. Use a thin piece of anything and scribe a line with a pencil along the actual cutter block using the blade as a reference surface. This gives you an accurate point on the cutter block to make the measurement from. You don't need to measure from top dead centre of the block if you use this technique.You need to get the edge of the infeed table at the same height all the way along its edge from the cutter block. This ensures that the infeed table is aligned and parrallel with the cutter block.

I use a OneWay measuring block to set mine when it needs doing. They are fabulous for all sorts of setting up. But they are not cheap and I had to order mine from the USA. The Wood Whisper has a video on uTube on setting up a planer Thicknesser that you might want to look up. He uses a few measurement systems, one of which is the OneWay

If I'm still not very clear I will try to draw it for you and post.

 

[wcndave]

Thanks, clear now! I have been setting to the out feed table which should be parallel to the block. I watched all of marc's videos, however perhaps time to review a few.

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