Jet Jpt310hh - tables not quite flat

[Psych 101]

Finally got my jpt310hh from Gregory's. Spent most of today getting the jointer tables coplanar again (this was nowhere near right after Gregory's changed the standard head over to the hh). I haven't had time to run any timber through yet but I have noticed both tables have a slight bow/sag in the middle.

I have a veritas 38 inch straight edge and when I sit this on the infeed table only there is about a 0.15-0.2mm gap under the middle of the straight edge (measured with a feeler gauge). Is this an acceptable deviation? The outfeed table is similar.

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[Mr Brush]

So was this a used machine before it was converted to the helical head, and if so how old??

I assume it has been correctly transported and not lifted by the ends of the tables?

I considered converting my standard head JPT310 as well, but didn't feel that the quality of the machine overall justified the spend. The ribbed finish on the cast table surfaces may well reduce friction, but it also means the timber is only running on the small amount of material at the tops of the ribs. This will inevitably wear faster than a conventional flat surface on the tables. My machine works fine as is, so I spent the money on a JET 16/32 drum sander instead as a follow-up step to the JPT-310.

I've used enough helical head machines to know that they are truly fantastic, but there are some really cranky grained timbers that still tear out a bit. The drum sander can handle ANY timber, and has the benefit of being able to do veneers down to thicknesses I wouldn't dream of trying to put through a thicknesser.

If I'm in the shed today, I'll check the flatosity of the tables on my 5 year old JPT-310 and let you know what I find. Like you, I also spent a very long time getting the tables coplanar when the machine was delivered !!

[Psych 101]

My machine is brand new. I would be interested to know if this is common to other jpt310s as well or just mine.

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[Mr Brush]

I'll stick the straightedge on my JPT310 and let you know. A 0.2mm gap does sound a bit much to be acceptable I agree.

[Mr Brush]

Psych101 - you have a PM !

[CharlieZ]

I bought the Jet310HH earlier this year and had a similar co-planar problem, but mine was the in-feed table that sagged about 0.3mm to the outside, and it was a bit out front to back at the cutter-head as well. Two things helped, first I watched Marc Sapgnuolo's video at his Wood Whisperer site (video #118 I think) in which he walks though using the long straightedge and feeler-guages to sequentially adjust the in-feed table. I also downloaded the US JET Model JJP-12HH Operating Instructions and Parts Manual (Part No. M-708475) for details on the adjustment points - the Oz manual is hopeless for this. It was a slow process resetting the machine to check levels after each small adjustment, but after a couple of hours I got it pretty much dead on. Trick is to be patient - a small adjustment to the grubscrews makes quite difference, so best to creep up rather than overshoot.

[Mr Brush]

CharlieZ - yup, as I've said elsewhere, the JET USA manuals are essential reading for setting up machines properly. The manuals supplied locally are crap.

Like yours, my standard JPT-310 was delivered with the tables hopelessly out of alignment. It took several hours to get them coplanar to my satisfaction, but I haven't had to touch the adjustment since. I can't decide if stuff changed alignment in shipping, or whether they don't even bother to check this at the factory.....

JET is better than the really cheapo brands in that they have SOME factory QA (as opposed to none), but they can still require a lot of fine tuning to get the best out of them.

[Psych 101]

I dont have a coplanar problem. My problem is the tables aren't flat.

Thanks for the advice. I have contacted Gregory's to make a warranty claim.

[Psych 101]

I have noticed a couple of other issues as well.

There is slop in the table height adjustment. When you move the lever the eccentric rod it is immediately attached to turns immediately but the other rod only starts to turn once the slop is taken up. The effect is that one side of the table moves before the other side (slightly). The tables are only coplanar in relation to the postion of the rods when set up and whether the last table movement was up or down.

Also the fence is ridiculously fiddly to make square to the table and changes every time you move it. Plus if you get one side square it can throw the other side out.

Only having frustrations with this machine so far.

[spartan]

I remember checking this out and going through the calibration from the wood whisperer, the only issues I had was getting the fence square but I solved that without much fuss.

[chocwheaton]

I recently picked up a used (made in 2010) jpt-310hh and have the same issue as you, but my outfeed table has a dish 0.4mm deep, roughly in the middle of the table. Mine is also not a co-planer problem. Its a table flatness problem.

I just started a thread in a slightly different part of the forum: https://www.woodworkforums.com/f155/j...y-need-179955/

What's been the outcome so far with your machine? Do you think the table un-flatness (is that word?) are impacting the straightness of the wood it produces?

Cheers

[Psych 101]

I took mine back and got a refund. It can be painstakingly setup to get reasonable results but the unacceptable aspect for me was repeatability. Any time you moved anything the calibration needed to be redone (which can take hours). The tables were not moving in parallel due to the slop in the height adjustment. The fence was also an absolute pain. This machine would have driven me nuts if I had to use it on a regular basis.

[chocwheaton]

Shame taking it back isn't an option for me. I might have to consider getting the tables ground flat. But doing that to discover other inaccuracies would be hell.

Maybe I should have bought a hammer combo machine?

Did you buy something else to replace the jet?

[Psych 101]

Shame taking it back isn't an option for me. I might have to consider getting the tables ground flat. But doing that to discover other inaccuracies would be hell.

Maybe I should have bought a hammer combo machine?

Did you buy something else to replace the jet?

I am now looking at the hammer.

[elanjacobs]

For what it's worth, I have contacted Jet for comment on the problem since it seems to be a common issue. I'll report back with their reply.