Thread: Edge Jointing Problem

Are you jointing a face first then holding that face against the fence to joint the edge?
Double check your fence is at exactly 90°
Concentrate the downward pressure on the workpiece on the outfeed side of the jointer.

First off, you should use power tools in anger.
I am confused, when you say "slope" do you mean the width is different across the leading face to the trailing face? Or is the edge out of square with respect to the face?

Originally Posted by NCArcher

Are you jointing a face first then holding that face against the fence to joint the edge?
Double check your fence is at exactly 90°
Concentrate the downward pressure on the workpiece on the outfeed side of the jointer.

Hiya,
Thanks for the reply.
No im not putting a face through first. The boards are flat and square to start with.
Fence is set to 90 degrees and confirmed this with my incra sqaure.
I've been concentrating the downward pressure on outside part of the table.

Originally Posted by ClintO

First off, you should use power tools in anger.
I am confused, when you say "slope" do you mean the width is different across the leading face to the trailing face? Or is the edge out of square with respect to the face?

The first I believe, so its starts the same - and ends different, from a measurement perspective its only like about .5mm but you can detect it with the eye, it then get worse with subsequent passes. The edge remains flat - ie, no gaps between it and a flat surface.

Another point of clarity, the machine is in mobile.
I chucked a level on the table surface - a look at the bubble, shows that its level is out by a hair - i.e, ,you have to look for longer than a glance to see the bubble isnt perfectly in the centre. It seems as this is consistent with the floor - I position the machine near the roller door so a lot of the dust can be pushed out the door.

So is it possible that this is root cause - the machine is parallel with the floor which has a slight slope towards the door???

The fence hasn't got a twist in it has it? The fence on my jointer has a slight twist in it, so I make sure the when I set it for square, that I do so just pass the blades on the out feed side and keep the boards press against this part of the fence to keep it the same for the rest of the board.

When you say slope, I assume you mean that the board ends up being narrower at one end ie not parallel , even though it is at 90 degrees to the flat side?

This can happen in a couple of situations. Firstly, If you are pressing down on the front of the board as the edge feeds across the jointer blades, this can cause the "slope" to occur if the leading edge is shallower than the rest of the board. ie you end up taking too much off the front end when in fact none should come off in the first pass. You should put more pressure further down the board to ensure the shallow end does not get planed in the first instance.

Other situations when this can occur is where the board is warped or has a high/low spot in the middle. Your technique will determine whether the jointed edge ends up being parallel to the other side of the board.

You have checked the table for level (unimportant) but have you checked that the infeed and outfeed tables are parallel?
It matters not if the tables are not reading level with a spirit level. What is critical is the tables must be parallel with each other. In other words, when the infeed table is lowered to make the cut, the clearance under a straightedge laid full length along both tables should be equal at both ends of the infeed table. An easy way to check this is to lay a full length straightedge along both tables, Place a small piece of paper under the straight edge at both ends of the outfeed table, lower the infeed table enough so a piece of paper can be slipped under the straight edge at the tail of the infeed and another piece at the head end of the infeed table, raise the infeed table until all four pieces of paper are held tight between the straight edge and the tables. Test both front and back edges of the tables.
Hope this helps.

Hello Spartan.
are the jointer blades parallel to the outfeed surface? To check this unplug the machine, lay a piece of straight hard timber( 500mm or so long) on the outfeed table next to the fence so that it passes over the cutters by 50mm or so. Mark the point where the timber leaves the outfeed table at the cutterblock end. Put slight finger pressure on the timber near the centre of its length and roll the cutterblock toward the infeed table as in cutting. A knife should pick up the timber and move it toward the infeed table. Mark this travel on the timber at the end of the outfeed table. Be careful not to nick the timber when doing this. Roll the cutterblock back and move the timber to the opposite side if the outfeed table from the fence and repeat. If the movement of the timber is the same go to the next knife and repeat. Do this for all your knives. I have an old 10" woodfast jointer and my distance of movement is 4 to 6mm. If you have differences over a couple of mill it may be that the lifting and reseating of your combo is allowing dust to put things out a little.
Cheers, Tony.

Originally Posted by spartan

Hi Guys,

I'd like to tap into the collective brains of people with edge joining/jointing experience.

I'm just starting to use my jet combo planer/thicknesser in anger and have started to attempt to join some boards together. I've started with a couple of DAR board purchased from bunnings. I check them before putting through the jointer and they are pretty much square.

My plan has been to take a couple of 1mm passes and then join the edges together.
What I am finding however, is the my boards are ending up with what I can only describe as a slope on them.

I've checked my technique a couple of times, and whilst im sure its not 100% I dont think it a major contributor - but I could be wrong.

the board edge ends up flat, i.e, there is no gap when put up against another flat surface.

They start square with the short edge but dont end up square....

Not sure where to start looking...any advice appreciated....

where abouts are you in brisbane?..........bob

Originally Posted by noty

Hello Spartan.
are the jointer blades parallel to the outfeed surface? To check this unplug the machine, lay a piece of straight hard timber( 500mm or so long) on the outfeed table next to the fence so that it passes over the cutters by 50mm or so. Mark the point where the timber leaves the outfeed table at the cutterblock end. Put slight finger pressure on the timber near the centre of its length and roll the cutterblock toward the infeed table as in cutting. A knife should pick up the timber and move it toward the infeed table. Mark this travel on the timber at the end of the outfeed table. Be careful not to nick the timber when doing this. Roll the cutterblock back and move the timber to the opposite side if the outfeed table from the fence and repeat. If the movement of the timber is the same go to the next knife and repeat. Do this for all your knives. I have an old 10" woodfast jointer and my distance of movement is 4 to 6mm. If you have differences over a couple of mill it may be that the lifting and reseating of your combo is allowing dust to put things out a little.
Cheers, Tony.

The machine has a helical head. So I'm not sure this applies?

Originally Posted by robyn2839

where abouts are you in brisbane?..........bob

Northside, Cashmere.

Oops

on rethink, it may still do-I have no experience with them- yet. I guess you could still try the closest and most distant cutters from the fence and see. No need to do all of them. A piece of hardwood no wider than the individual cutters might help. I have seen these spiral blocks at Gregory's machinery in Bris - the machining looks pretty out there - very clever.
Tony.

Originally Posted by spartan

The machine has a helical head. So I'm not sure this applies?

Spartan, unless I have misunderstood your original post, the problem lies with your technique. Concentrating pressure on the outward table for the length of the board can cause the problem you describe if there is a convex kink along that edge.