Thread: Settng jointer blades

what a great idea. that will be my way of setting them from now on
thanks
les

Originally Posted by Fencepost2

Something that is working for me very well when I am setting the blades in my jointer is the use of a pair of cheap welding magnets. They are the strong magnets rivetted inbetween two steel corner plates and cost only a couple of dollars each. I smoothed the steel edges with a stone to remove any burrs. Then I raise my infeed table to the same height as my outfeed table, checking with a good straightedge. Then I snap a magnet across the gap on each side of the 10 inch table. The metal side plates on the magnets are then at the same height as the tables. When I rotate the cutter head to top dead centre the magnets pull (helped by the internal springs) and hold the blade up to the right level while I tighten it. Works a treat.

Hi Fencepost2

A some pictures would be nice as I can't quite see it in my head.
Thanks
SB

Will try to arrange a pic, may take a day or two to get the camera organised.

But your blades should be set slightly higher than the outfeed table to work correctly!

The method you have will still work but the cutters must be set slightly before of after top dead centre, so when at tdc they will be higher than the outfeed, this distance varies depending on feed speed and softness/hardness of the particular timber to be jointed.

Just back the out feed off a bit afterwards. That's what I do.

There is a video around here somewhere by a forumite showing this method using large bar magnets. Definitely the easiest way to set blades.

I always set my blades level with the outfeed table and am wondering why people are saying they should be higher, doesn't this cause snipe on the last couple of inches or even worse a board that is not straight when the timber ceases to be supported by the infeed table and it's weight shifts to the outfeed table?

Edit: pretty sure Gumby did the video.

I don't know why but the blades always need to be slightly proud of the out feed. We're talking fractions of a millimetre.

Have a look at the bottom of a hand plane. The blade protrudes from the bottom, yet you end up with a flat board and no snipe at the end. How does it work? Beats me...

Originally Posted by silentC

I don't know why but the blades always need to be slightly proud of the out feed. We're talking fractions of a millimetre.

Have a look at the bottom of a hand plane. The blade protrudes from the bottom, yet you end up with a flat board and no snipe at the end. How does it work? Beats me...

Perplexing isn't it! I can't get my head around it either but think I will stick with level with outfeed for the moment (until someone can explain why and convince me otherwise) as I get good results this way.

Happy jointing,
Burnsy

I get good results this way

I think that's the most important thing.

I set mine flush with the out feed using magnets, then I plane a board and check it and adjust the out feed up or down until I get what I want (a straight edge).

A couple of things I have found when using magnets,

• do not hold four large bar magnets in your fist when walking past the jointer, your knuckles won't enjoy the experience when your hand is sucked into solid steel at mach one.
• if you loosen the blade too quickly it can shoot up into the magnet and may get nicked.
• I found the magnets get in the way when going through the tightening sequence, if you move them they can move the blade. Fiddle, re-fiddle, fiddle etc.

So far the best method I have used is the single stick of wood and a pencil mark. This has been documented before, but essentially you lay the stick on the outfeed table and make a mark on the stick at the end of the table. Rotate the blade cutter and see how far the mark moves from the edge. It should only move 1/8". Use a short block of wood to tap the blade down until it is "just right". It should take no more than fifteen minutes to do all the blades. I tried this method originally, then went to gauges and magnets, and am now back to the stick and pencil (thanks Col).

If you really want to give the magnets a go, sit them on a piece of thin paper to get that extra bit of height.

How do the blades mount in the cutter head on your jointer, Groggy?

Try putting a dial gague on both sides of your blade and see if the protrusion is equal. Using the magnet will not hold the blade in position once you start to tighten the restraining bolts. Any tiny imperfections in the mating surfaces can result in movement of the blade as you tighten.
Check and you will see this to be true.


Ross

Originally Posted by silentC

How do the blades mount in the cutter head on your jointer, Groggy?

Three blade cutter head with each blade set on two spring mounted blocks. Each block is adjusted by hex nut to change the height. There are four lateral tension bolts on each blade that must be tightened by "loosening" them. i.e. they tension the locking bar by pushing from the cutter block onto the blades, I'm sure you know what I mean if you've seen a few jointers. A pretty standard setup.

Yeah, mine is much more basic than that. It has a floating gib with four hex bolts that you loosen to tighten. You have to hold the blade in the correct position and then tighten the bolts because the blade just floats - there's no height adjustment or spring blocks. It's a right pain in the asre. I've tried the tapping thing but you tap one side and the other side moves if you leave the bolts loose enough for the tapping to do anything and if you tighten them a bit, you have to tap the blade so hard it goes too far.

Easiest way I've found to set mine is to use the magnets, one at each end of the blade - do up two gib bolts and then take the magnets away and tighten the other two. I use the ruler trick to check the blades. There has to be a better way but I haven't found it yet.

Ross, you're probably right about the blade deforming when you tighten it. I just hope that at least one of the blades covers each low spot in the other two