Planer Knife settings, tolerances

[jeth chiapas]

Hello all, just in the process of getting a new 15" import planer set up, been the best part of the morning fiddling with the knives.

The problem I am having is that the knife always seems to end up a little high after tightening the gib nuts. I tried various ideas including clamping a piece of wood across the top of the planer with a tee nut and bolt protruding to lock down on the top of the setting guage whilst tightening the bolts, this improved things but I still find that once the firmly locked down gauge is removed and I recheck the blades the guages feet no longer seat on the head.

In the end I decided I was tired of loosening, clamping tightening and unclamping so I figured I'd let them all sit where they want to. Pushing one of the gauges feet down and using a feeler guage under the other I am getting between 2 and 4 thou, this is actually double the discrepancy as far as I can tell as the gap each side will add if measured one side. so in theory they are within a thou or so.
Does this sound OK? The manual says to keep tolerances within 2 or 3 thou so I think I'm cool, just wanting to check this by folks here as this is first time set up... you know

[John TenEyck]

As long as you have the minimum required knife depth in the head I don't think it matters much on a planer how far out the knives protrude, assuming of course there's clearance for the rotating knives. On a jointer the knives have to be even with the outfeed table; but on a planer I see no reason it really matters. Your difference of 0.001" side to side over 15" is very good, probably as good as they would come from the factory. BTW, why did you have to adjust the knives? Weren't they already installed and set when you got the machine?

[Bill White]

I have a DeWalt 733 planer that has magnetic setting guides. I've never had an adjustment problem.
Are you setting a planer or a jointer? On my jointer I use a piece of glass set on the outfeed table.
Bill

[jeth chiapas]

Thanks for your reply John.

This is first set up, I am going through all adjustments to make sure all is ok, 3 of the knives were not far off, one was a fair bit out one side,so good job I checked.

Going through the manual I have now encountered another problem, or possibly two.
Firstly the chipbreaker is higher than the stated spec when at it's lowest position. The manual says the chipbreaker should be set with the shop made gauge block to .004" below the blade height.
The lowest I can set it is a little above blade height at one side and about level in the middle moving to correct height the other side. I have removed the set screws which are of no use once the plate is bottomed out and could become loose inside the machine as only held in by the width of the tapped metal bracket they fix into. I have also wedged the plate under the sprung brackets with some wooden blocks to push it as far down as possible and stop it riding up.
It seems the problem is that the c shaped chip breaker piece is welded our of parallel on its mounting plate, so one side doesn't extend down as far as it should.
Is the set up I have going to be OK or do I need to wait to be told the part has to come from China and would I please wait 6 months?

Lastly, the manual includes set up details for the "pressure bar", on the diagram it is a flat metal strip which sits behind the head. My machine doesn't have this part... The manual is as expected from an import, a generic photocopy, seems to be from a steel city model. Is my machine a slightly different model which doesn't use the pressure bar or am I missing bits?

[John Aperahama]

Jeff
These things are all the same no matter whose sticker that is stuck on them. The only real difference is motor over or under. So unless it is a real oddball I would not sweat it. By all means check the knives they they spin at some un-godly speed. I am guessing that it may not be a grizzly machine their manuals are usually very good. Toss the manual you have and download the generic model manual from grizzly see if that helps. Just had a look at the manual GO453 which does not have the pressure bar as compared to the GO454 which does have the pressure bar specifically part no 75 note that the parts breakdown is in the same manual. Confused now?

[Rod Sheridan]

Hi, the knife projection on a planer is critical because as you've discovered the chip breaker and pressure bar have to be adjusted relative to the knife cutting circle.
I
f your cutting circle is too far out of whack, the adjustments for the chip breaker and pressure bar won't have enough adjustment range.

The knives also shouldn't project more than the design value to avoid bending, chipping or having excess vibration from knife deflection.

As it's a new planer, get it replaced, or replace the defective parts now before it's out of warranty. You don't want to spend the next 10 years cursing the planer every time you change the knives.

Regards, Rod.

[jeth chiapas]

Thanks for your thoughts, exactly what I was just doing, I pulled up a jet manual which is a near identical machine and doesn't have the pressure bar so i think I will stand well back, push the on button with a stick and see how she goes.

I am a little concerned about the chipbreaker as I believe that to be fairly crucial to safe operation though I'm thinking that with anything but the finest of cuts it will still be contacting the material before it hits the knives, which I guess is the point.

[jeth chiapas]

Just reporting back, the final adjustment to the outfeed roller was also troublesome, not within spec at lowest point of adjustment but I just levelled it up both sides.
Seems to be producing too parallel sides, and the finish isn't bad at all, smooth with the faintest lines, not glassy but this was a fairly soft fibrous wood so will have to see how she performs on other materials.

Thanks for all your comments. Ordeal over

[Steve Baumgartner]

First of all, set within a thou or two is quite acceptable, so if you are getting there, don't lose sleep!

It is normal for many types of jointer and planer knives to rise a bit as you do the final tightening of the bolts. The movement makes accurate setting a fiddly business. Here are some ideas that may help. For one thing, make sure you are not cranking them too tight. From fear of blades sailing out of the head, many of us gorillas overtorque them to the point that the head actually deforms. Don't tighten any nut all the way in one go; creep up evenly across all the nuts. Try to be careful to get all of them, both across each blade and from blade to blade to the same torque. When the height needs to match something else (such as chip breaker or non-adjustable outfeed table), set them initially a tad low so that they rise to the needed final height. This takes some practice to learn just how far your knives tend to rise. A dial indicator is extremely helpful for this process.