newbee jointer issue

[drchristian]

I have a 6"jointer and I am trying to edge joint a board to glue up a table top. I have outfeed table even with blades. I have infeed set for 1/8. The board is 72" long. If I lay a straight edge on board I can see a slight, maybe 1/16 gap in the middle. Jointing is not taking it out. I feel stupid why is the jointer not taking it out? I get a cut all the way down the board. I am puzzled? Help please!

 

[nn4jw]

If you set the infeed and outfeed even with each other and check with a straight edge are the infeed and outfeed tables level and co-planar? It's possible that they are not and are creating a slight "hump" in the middle.

 

[JohnnyR]

As you push the board through, make sure there's pressure on the outfeed table. Also, 1/8 is a huge amount to take off in one pass. You're also dealing with a very long board for the short bed of a 6" jointer. When you put the boards together, if there is only a very small gap in the middle and you can clamp it tight, just glue it up. Many feel this is the preferred way.

 

[CDPeters]

Also, be sure to feed your board concave down - so that the high spot in the middle of the board is up, not down. Once you have one edge straight, then rip the other edge straight and parallel on the table saw. One light pass of the ripped edge on the jointer if you need to clean up saw marks.

Definitely as Jim suggested, be sure your in and outfeed tables are co-planer.

 

[drchristian]

Reset the planer up with a machinist straight edge. The infeed and outfeed table are witin 3 thousands and all three sets of blades just touching straight edge. It is better but still puts a slight 1/16 arc in center of long board. It is a used Chinese planer so it is probably good as I can expect I guess. I think they will pull together with biscuits and glue and clamps. Thanks to everyone for your help

 

[nn4jw]

Take a look at this link.
http://www.newwoodworker.com/jntrprobfxs.html

There are some tips that might apply to your situation there.

If your long board is already a little concave then I agree with John who in an earlier post said your board just might be too long for that jointer. My 6" jointer would probaby have the same issue. This would probably be one of those cases where I'd break out my jointer hand plane to get a nice straight reference edge, especially if I only had one or a few of these boards to contend with. Then use my table saw to rip the other side parallel.

 

[Berta]

Are you pressing mainly down on the board as you are jointing (incorrect), or towards the back fence (correct)? That is how I fixed my problems with the jointer. It should be set closer to 1/32 of an inch difference.

 

[bluedawg76]

Are you pressing mainly down on the board as you are jointing (incorrect), or towards the back fence (correct)? That is how I fixed my problems with the jointer. It should be set closer to 1/32 of an inch difference.

my thoughts as well. sounds more like technique than machine setup. just to recap:
outfeed should be 0.002-0.005" lower than the blades at top dead center (TDC). All blades (3) should be the same height and parallel (use a dial indicator w/ a magnetic base. Fairly cheap at Harbor Freight). John White has a great book on machine setup called Care and Repair of Shop Machines. Definitely a good resource for setups.

The nonsense about your jointer beds being too short is not true IME. I'm assuming this is a 4 ft jointer (~2 ft outfeed). Theoretically there are some arguments that it won't work well -I've heard them, but in practice, you can joint 8ft boards provided you can support them. Not sure why the 2ft jointer plane would have any less limitation given the reference bed is significantly shorter.

for final passes, take off <1/32" -try to sneak up on flat rather than get it in one giant pass. 1/8" is way too much. Same is true for thickness planers.

Reference the board against the fence and outfeed table meaning that's where pressure is applied. DO NOT press down on the board as it passes over the cutter head. You're not trying to bend the board into flatness, you're removing the excess wood. I'm guessing this is your issue.

A slight gap in the middle is fine, if not preferred -called a spring joint. 1/16" is probably too much though. I'm thinking 1/64" i.e. a slight gap that can easily be closed with minimal clamp force.

For edge jointing, biscuits aren't needed and don't offer any additional strength. Honestly, they're more work and a pain if you get much glue on them. They can swell quite a bit and cause "humps" in the board til they dry out.

don't forget to align the grain in your glue-up going the same direction. Makes the final planing of the panel much easier.

 

[Touchwood]

A lot of excellent suggestions already. Once you're sure the tables are co-planar, setting the knives correctly is the other challenge. I've seen many different ways of accomplishing that, but this article works well...doesn't require any magnetic jigs or dial indicators. I've been using this method for years. It's simple and it works.
www.woodcentral.com/bparticles/knife_adjustment.shtm

 

[ehpoole]

In our Articles area you can also find an article I wrote many years ago covering the complete setup of a jointer. Nit us rather long as it covers a lot of ground, but you may find some useful hints to help you out.

http://www.ncwoodworker.net/forums/...er-Setup-and-Knife-Installation-and-Alignment

If you have verified that your jointer's tables are absolutely coplanar with one another over their length then your next step is aligning the knives properly. It can help to characterize you jointer table with a dial caliber or straightedge and feeler gauges as the table itself is often not perfectly flat (and the cheaper the jointer the less likely it is to be perfectly flat) which can lead to some knife alignment errors if you are not aware of possible dips or hills in the table in the immediate vicinity of the cutterhead.

If if you really have 1/16" of cupping in your freshly jointed board then that means: 1) if over the length of the board then either the tables are not coplanar or the original board had a tremendous bow over its length to start with, or 2) if over the width of the board then the knives are not properly aligned relative to either the cutterhead or table (which you align to is partly decided by choice and/or the type of cutterhead your jointer has). If that 1/16" of cupping is over the width of your board then that is so extreme an alignment issue you should be able to easily see the problem if you sight the knives down the length of the table while slowly turning the cutterhead.

My general rule regarding the maximum length board that can be trivially jointed on a jointer with minimum skill is a length equal to twice the length of your jointer's shortest table. As you get longer than that it requires increasing skill and attention to details to properly joint. It is not a major limitation, usually, if the board started out close to perfect, but the more extreme the defects in the original board, and the greater the length of that board, the more skill and attention to detail it requires to properly joint the board so that it comes out flat (sometimes strategy is required for such boards).

Since you are presumably new to Jointers, do not forget to use push pads where appropriate to guide the board through to protect your hands in the event of a kickback event. Kickback is rare on the jointer, but it can happen and when it does it can leave your fingers and hands very exposed when the board suddenly disappears from beneath your hands...it is better to sacrifice some plastic or wooden push pads then flesh. Kickback risk is elevated the more you try to remove in a single pass with a jointer and also varies by the properties of the wood itself and the sharpness of your knives. A 1/8" pass is about the most one should ever seek to remove in one pass with 1/16" per pass a more reasonable maximum per pass when dealing with hardwoods. Remember that jointers are only intended to flatten two perpendicular sides at right angles to one another, not to actually dimension lumber as dimensioning lumber is what the thickness planer and tablesaw are intended to do -- the jointer just prepares the first reference sides by flattening them, so that your planer and tablesaw can do their jobs accurately. I seldom have my jointer set any deeper than 1/32".

Good luck and I hope you resolve your issue soon. Initial problems can be challenging but they also teach you quite a lot about your new tool, making you better equipped the next time there is an issue to sort out.

 

[drchristian]

Thank everyone, I thinking it is my technique. It is a 4/4 board and there was not a noticable bow in the board to start with. The Planer is a Northstate 6" with total 42" bed. I set it up with a 36" machinist straight edge and it seem to be co planer. I could only get a 3 thousand feeler guage under it at a couple spots. I can plane a 4' board on it and it is perfect. Yes I was pushing down on the board to keep it flat (2x6) on edge. Maybe I was pressing to hard. I need to get some cheap scraps to practice with. I was kicking myself trying to decide if it was technique or planer issues. I personally know Tom from the new woodworkers article. I may have to run him down to talk to him. Inread the article. I been looking at the jet 8" longbed jointer it is about vall I could swing finiancialy but if it is me causing the issue I doubt it would help. I guess I just need to practice.