Planar changes thickness (settling?) during first run

[mark mcfarlane]

I'm trying to get a repeatable thicknessing workflow.

I have a Wixey WR550 digital planer gauge installed on my CU300 combo machine.

If I set the thickness on the Wixey gauge to, for example, 0.75 inches and lock down the planer bed, the Wixey reads 0.725-0.735 after the first board is planed then the gauge seems to fluctuate around 0.735 +/- .015 for subsequent boards.

It seems strange that the planar bed moves upward toward the cutter during the first cut. I suspect the problem is that the mount I created for the digital gauge isn't stiff enough, and is moving a little during the first cut.

Running three short pine boards through the locked thicknesser shows they are the same, +/- .003"

Maybe I am expecting too much precision from this machine and the Wixey.

Anyone have an experience to share?

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[Jamie Buxton]

It seems important to distinguish between the planer bed moving, and the height gauge moving. Measuring the board itself will tell you which it is. My bet is that the Minimax is not moving, and your problem is something to do with the aftermarket gauge.

[Rod Sheridan]

Hi, on a single post planer the infeed and outfeed end of the planer can move during planning.

This doesn't affect the workpiece as the work is directly over the post and under the cutter, however it could affect a gauge mounted on the infeed or outfeed.

My planer has a mechanical gauge in the height wheel, it's always accurate............Rod.

[Bill Dufour]

Agree, measure the thickness of the boards and see how they vary and how that compares with your mounted gauge.
How are you accommodating backlash in the thickness setting. Do you always crank it up for final setting?
That arm with the slot looks way to thin to me. I would replace it with angle iron with just two mount holes and no slot.
Bill D.

[mark mcfarlane]

Agree, measure the thickness of the boards and see how they vary and how that compares with your mounted gauge.
How are you accommodating backlash in the thickness setting. Do you always crank it up for final setting?
That arm with the slot looks way to thin to me. I would replace it with angle iron with just two mount holes and no slot.
Bill D.

Thanks Jamie, Rod, and Bill.

I always set by moving the table up towards the cutter, and back off a 1/4" or so and reset if I go too far.

I'll try to mount something sturdier for the gauge.

Rod's point is interesting, that the table can wiggle in this massive 1 column configuration, but the cutter remains stable,....

[Andrew Hughes]

Could also be sign of dulling knifes. Or if you have the insert head too big of a cut with dulling inserts.
When I see weird things happening on a machine first order of business is the blades.

[Bill Dufour]

Your depth of cut adjustment procedure is wrong. Do it the way you have been doing but then crank it up just enough to remove backlash. Sounds like the table is going down into the backlash of the height adjustment. How far do you have to turn the crank to change direction, that is the backlash . My Parks planer has about 1/4 turn of backlash so i always adjust up into a deeper. I adapted a wheelchair brake to lock the adjustment handwheel.
Bil lD.

[Michelle Rich]

the important thing is : are the boards within specs? And heck leave them sit for a few days and let moisture get in, or out, and shazam they are all different thicknesses. This is woodworking, not precision cnc work.

[mark mcfarlane]

Could also be sign of dulling knifes. Or if you have the insert head too big of a cut with dulling inserts.
When I see weird things happening on a machine first order of business is the blades.

Andrew, the knives are M42 Tersa knives with maybe 200 linear feet run through them. Hopefully they are still sharp.

[mark mcfarlane]

the important thing is : are the boards within specs? And heck leave them sit for a few days and let moisture get in, or out, and shazam they are all different thicknesses. This is woodworking, not precision cnc work.

Hi Michelle. This is a combo machine. I want to be able to go back to a new setup after a few days and get the (closest) same measurements. A few hundredths of an inch difference between hardwood rails and styles turns into a lot of hand sanding.

[mark mcfarlane]

Your depth of cut adjustment procedure is wrong. Do it the way you have been doing but then crank it up just enough to remove backlash. Sounds like the table is going down into the backlash of the height adjustment. How far do you have to turn the crank to change direction, that is the backlash . My Parks planer has about 1/4 turn of backlash so i always adjust up into a deeper. I adapted a wheelchair brake to lock the adjustment handwheel.
Bil lD.

Thanks Bill.

Edited:

This machine has ~ 1/64 turn of backlash, but shows much more backlash on the Wixey metering system, again, pointing to a 'too flimsy' mount. The mount bracket I used was just some scrap I had lying around, the one supplied by Wixey wasn't long enough.

I'll get some stiffer steel for the mount.

[Michelle Rich]

I see..I doubt I have ever worked to those tolerances..interesting. Enjoy your woodworking

[Dan Friedrichs]

Mark,

Rod has it right. The center post design allows infeed and outfeed to flex, but the center stays fixed. I've seen the same thing on my C3-31. So your gauge will change measurements as the board passes through. You just need to get it calibrated such that it agrees with the thickness of the board upon exit. Obviously, the Wixey calibration procedure (for this DRO) is designed to do just that. Then you can set it to the desired thickness, and ignore however it changes as the board passes through.

I don't think it says this in the Wixey manual, but I think there are "+" and "-" markings on two of the buttons, such that when you put it into calibration mode, you can press those to bump the calibration up/down by 0.005". I find that more convenient than trying to wedge a board into the calibration slot and holding it perfectly flat.

I agree that your mount looks a little too flexible.

[Warren Lake]

center post can have movement from front to back and its also side to side. I run most in the center then jointing try to work more to outsides to even out the wear

[mark mcfarlane]

Mark,

Rod has it right. The center post design allows infeed and outfeed to flex, but the center stays fixed. I've seen the same thing on my C3-31. So your gauge will change measurements as the board passes through. You just need to get it calibrated such that it agrees with the thickness of the board upon exit. Obviously, the Wixey calibration procedure (for this DRO) is designed to do just that. Then you can set it to the desired thickness, and ignore however it changes as the board passes through.

I don't think it says this in the Wixey manual, but I think there are "+" and "-" markings on two of the buttons, such that when you put it into calibration mode, you can press those to bump the calibration up/down by 0.005". I find that more convenient than trying to wedge a board into the calibration slot and holding it perfectly flat.

I agree that your mount looks a little too flexible.

Thanks Dan, the combination of the center post / table wobble and the flimsy gauge holder appear to be my problem.

My only concern was that the meter reading changed after passing the first board, then it stays stable enough. The board thickness are matching the meter reading (after it settles after the first board is run through) to within a couple thousandths of an inch, which is probably beyond the resolution of my iGaging caliper.

I'll update the gauge holder and hopefully the gauge reading will stay consistent before and after passing the first board.

[mark mcfarlane]

center post can have movement from front to back and its also side to side. I run most in the center then jointing try to work more to outsides to even out the wear

Great point Warren, thanks for pointing this out. Thats a good workflow, particularly for doing the width thicknessing of rails and styles. I'll make sure to run them through the center of the thicknesser, over the post.

[Warren Lake]

Mark I dont know your machine, you put some photos up but I didnt see the center post sort of surprised they still make them that way as mine are likely 50 years old or more but maybe they need to in the multifunction machines

[mark mcfarlane]

Mark I dont know your machine, you put some photos up but I didnt see the center post sort of surprised they still make them that way as mine are likely 50 years old or more but maybe they need to in the multifunction machines

Here's the center post for the thicknesser.

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Warren, I'll respond to your PM later I need to eat.

[Warren Lake]

thanks Mark

clear they made the base stronger with the added plate there and its for side to side, but then being a newer machine possible the casting is not as thick as well. What about the underside where it attaches to the table is yours the same or is there a larger plate there as well?

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[mark mcfarlane]

thanks Mark

clear they made the base stronger with the added plate there and its for side to side, but then being a newer machine possible the casting is not as thick as well. What about the underside where it attaches to the table is yours the same or is there a larger plate there as well?



The top of the column attaches directly to the cast plate with no collar.