Jet JJP-12HH Table Flatness and Coplanar Adjustments

[Sanjeev Agarwal]

I just bought a Jet 12" Jointer Planer combo JJP-12HH. I thought I had it ready to go after putting it on casters and connecting it to 230V. But when I checked for table flatness and coplanar using my 2’ steel rule, they were really misaligned. I then bought a Veritas Steel 36” Straight Edge and Feeler Gauges to align but am struggling. Here are my issues.


1. The infeed table has a dip in the middle of the table of .010”. I thought a jointer’s tolerance is close to .003”. Is this an acceptable tolerance for a 12” jointer? If not, what options do I have?

2. I am unable to get the two tables coplanar. I aligned the outfeed table with the cutter head and then raised the infeed table until one end of the infeed table aligned with the outfeed table. This was the back left corner as seen standing in front of the machine. The front left corner was much lower – I could easily pass the 0.025” feeler gauge under the straight edge. When I try and raise the two adjusting bolts under the front of the infeed table, it not only raises the infeed table but the outfeed table also goes up! Has this got something to do with the fact that the two tables are connected as they are lifted together for conversion? If so, how do you move the infeed table without affecting the outfeed table? According to the manual this should just be raising the infeed table.

3. I am a little confused on the 4 adjusting set screws on the rear of the infeed table. The manual says they are for rear adjustment so why four? Do you move then equally in pairs? The back 2 are almost impossible to get into.


Any help from other owners of this machine would be much appreciated. Thanks.

[Russ Kupiec]

I don't know if this will help, let's hope it does, adjusting jointer tables is challenging at best. Marc Spagnuolo has a youtube that addresses tables with cam adjusters below http://www.youtube.com/watch?v=gO746...a9h4f&index=87 which I think still applies to any jointer with four support points for each table.
I've done this adjustment a few times and the bugaboo for me was realizing that the cutter head could also be adjusted with shims(AS A LAST RESORT) if the outfeed table doesn't end up aligning co-planar with the infeed table. On the current 8" jointer I have, I levelled the outfeed with the cutter heads but couldn't get the infeed to adjust coplanar. Two problems became evident. One was that the table will look stabilized with just three support points(like a stool) so I had to to stabilize one end of each table first then figure out which of the other two adjusters was creating the tripod, then creep the fourth adjuster into position without changing the plane set by the stool(3 adjuster support). The second difficulty for me was not testing the adjustment range of both tables. It is easy to get the outfeed to sit inline with the cutter head but.... the outfeed end may be too high or too low compared to the adjustment range of the infeed. It seems like you have another complexity created by the ability to flip up both tables for conversion to planing. I would still assume that one of the two tables still can be adjusted independent of the lift base.
I mentioned adjusting the cutter head support blocks with shims. There were factory shims inplace and they were not equal on both ends. Perhaps I'm dead wrong but the shimming, for me, ended up providing the adjustment to allow the outfeed tables to sit in a plane that was just within the limits of the adjustability of the infeed table.
Hope I didn't add to your problem.

[John Coloccia]

It's a pain in the butt, Sanjeev. The design for the rear supports amateurish. I'm not sure any other manufacturer does it better, but it's awful. What I suggest you do, since you're all out of whack anyhow, is adjust the two rear supports first until that end is co-planar. Then adjust the outfeed front support until the outfeed is parallel to the knife, and the infeed front support until the infeed is parallel with the outfeed.

Remember also that you can raise and lower both the infeed and outfeed sides of the table with the parallelogram mechanism. Don't focus so much on getting them "coplanar". Focus on getting two parallel planes. As long as you're not maxed out on the depth adjustment, you can set that later with the levers.

Since this is a jointer planer, do not change the knives to match the outfeed or you'll be adjusting the planar bed too.

Also remember that you'll have to adjust the lockdown mechanism anytime you adjust the the front support, and that you must take your measurements when you're locked down.

I believe that .010" is Jet's spec. Mine was out and they sent me a new machine....and that was a pain in and of itself. I you think uncrating this thing was a chore, crating it back up is a bigger chore.

[Fidel Fernandez]

I know this is an old post, but I want to show what I did and maybe this can help others with the Jet jointer/planner 12 inches. JJP-12


I tried to do the coplanar setting, starting from where the infeed table was. I tried for almost 2 hours, opening and closing the table so many times.
I managed to get it out of whack.


I decided to approach this like a normal problem, removing all the variables and starting from scratch.


This is what I did and I will refer to the picture so you can understand which screw I am talking about.
Jointer-Planner screws.jpg


One think to note is the SS screws (2 and 4) are easy to access from the back. You just need to remove the fence and when the table is down they are accessible from the back. Even the SS-1 is accessible from the back this way.


I removed all 4 setscrews (SS-1, SS-2, SS-3,SS-4) and the hex screws as well (HCS-1 and HCS-2).
I tight the 3 hex cap screws holding the table to body.


At this point the infeed table had no setup whatsoever.
I started with the HCS1, I put it back all the way in so the front left was at the lower setting.
I setup the infeed table (Left) to be at the same level as the out feed table, I didn't' care about the front right at this point.


I installed the second HCS (HCS-2) to make the infeed table level with the outfeed. I setup using the lever to move up and down and turning both HCS until after many tries the table was level. My straight ruler had no clearance. int the front from left to right.


I decided to start with the setscrews for the back.
I installed the SS-1 first, I clockwise the SS until bottom up, I didn't loose the 3 hex cap screws. This way the SS was touching the body of the jointer and making no effect (in other words, I zero out the SS).
The next step was to loose the 3 Hex caps and set the SS1 clockwise to raise the table. I tight the 3 Hex caps


The Left back was level, but it affected the Front, so I compensated setting the HCS again.


It was level again minus the back right.
I setup the SS-3 to level the back right. Same thing happen, it affected the rest so I moved tiny increments the SS-1, HCS-1 AND HCS-2 until everything was coplanar.


I was happy how the infeed table was coplanar with the outfeed table so I installed the SS-2 and SS-4 bottom up without loosing up the 3 hex screws so they were zero out in respect with the current setting, they didn't affect anything. I did this to keep it level.


It took me half an hour to do it this way.


I hope this can help some one and if you have another idea please post it.

[Cooper Anderson]

Fidel,

My Jet JPP-12 has never been properly adjusted. For the past week or so, I've been reading one horror story after another about the difficulty in adjusting the tables to be complainer on this jointer planer. Sounds like a complete nightmare.

Your description, however, is the most clearly written explanation I've seen yet. Now I almost have the courage to take this job on.

Thanks for your post. Much appreciated.

[Brian Behrens]

I know this is an old post, but I'm fighting this battle right now trying to get my tables coplanar on my Jet JJP-12. My outfeed table and knives are set perfectly. I have played with the indeed table for about 6 hours now, chasing my tail the whole time. I'm going to try Fidel's method tomorrow unless anyone has a better suggestion? (Besides selling it!!!)

[John Patric]

I have the 10" version, which I had to go through setting it up to be co-planar. I found that making small adjustments and checking (closing the tables and locking them down) regularly eventually got it co-planar. In Fidel's diagram SS-1 to SS-4 change the infeed table geometry as per SS-1 to SS-4's layout i.e. SS-1 raised raises the front left of the table and SS-3 the back left of the table. I used a Oneway gauge and Veritas straight edge to get mine co-planer. It took me about 4 hours on a Saturday afternoon to get it right. Patience, small adjustments and constant measuring of progress is important.

[Brian Behrens]

Ok folks. I went at it fresh today and followed Fidel's method to the letter. Inside of 30 minutes I had the infeed coplanar within .002" . My veritas straight edge has a tolerance of .003 so I think this is as good as it will get for me. His advice of removing the two rear set screws until you're done is the key. It is still a terrible design. I ran some test pieces and they were perfect . Thank you Fidel for writing this up!

[John Rambizzle]

I cannot thank Fidel enough for this write up. Finally got it coplanar.