Thread: Jointer tables - How flat do they need to be?

Well, I have a reply from Jet. Here it is:

Hi Elan,


Measuring 'flatness' over the large tables on the Jet JPT's becomes quite a difficult process, with many variables and techniques giving inconsistent readings.


Even then, determining what is acceptable flatness becomes difficult, as there is certainly no standard as such.


Generally the industry buzz (pardon the pun) seems to be that anywhere from .003" to .007" (so that would be 0.076mm to 0.177mm) measured with feeler gauges and a straight edge. Coplaner adjustment or table sag are probably more important that 'dead' flatness, and is quite often overlooked or mistaken as a manufacturing fault, when it is usually caused in transit (either from factory to ship, ship to destination, ship to warehouse, warehouse to warehouse, warehouse to customer...you get the picture), and should be checked on every set-up.


Here's where it gets tricky accurately measuring this flatness... even a good quality straight edge (like a Veritas units) have a stated tolerance of .003".


I think that many people get caught up in long and technical debates about flatness, and angular accuracy within 6 decimal places, and forget that the item they are machining has just swollen (or shrunk), and possibly warped, twisted and bowed, in the time it took to do the calculation.


That being said, I have not received any formal 'complaints' or feedback from actual customers regarding these tables. We will always respond to customer service or product quality issues, when they are brought to our attention via the correct channels ie: our customer service centre of showrooms, not via the forums.


Thanks for your enquiry, and I hope this helps you somewhat. Please feel free to contact me if you have any other issues.




Tony








____________________________________
Tony Forbes
National Wholesale & Product Development Manager
Carba-Tec Pty Ltd
128 Ingleston Road
Wakerley Brisbane Qld 4151
AUSTRALIA
p: +61 7 3390 5888
e: [email protected]
w: CARBA-TEC - Woodworking Tools and Woodworking Machines
















On Thu, Feb 6, 2014 at 5:08 PM, Elan Jacobs <[email protected]> wrote:
Submitted on Thu, 06/02/2014 - 5:08pm
Submitted by anonymous user: [220.239.209.141]
Submitted values are:


Name: Elan Jacobs
Company: Dewhurst Furniture P/L
Address:
City:
State:
Phone: 0419 527 227
Email: [email protected]
Enquiry: Table flatness
Comments:
I am a member of an Australian woodworking forum and have read a number of complaints from other members about machine tables not being flat. Specifically, the tables on the JPT-310 have been reported to have dips of 0.1-0.4mm. There are 4 separate mentions of this problem in the past few months and I was wondering if this is considered to be within tolerance?


Any comment you have on the matter would be greatly appreciated, as well as advice on if/how Jet will offer a remedy for owners.


Sincerely,
Elan Jacobs




The results of this submission may be viewed at:
http://www.jetmachinery.com.au/node/26/submission/66

For those of you who have worked through the coplanar alignment on the HH model, would it be possible for you to add additional clarity to what is in the us version of the manual.
Specifically, the process of setting the outfeed table to the reference of the cutter head , and also the grubs screws are you adjusting all four - there are one either side of the 13m bolt and then two that are harder get to on either side of the third bolt.

For what its worth - I've had mine from three years and the table was pretty close to coplanar - I didn't notice a dish in the tables previously - but after reading this thread I noticed it has about .007 inch dish on the in feed table about 75-100mm before the cutter head and then is flat from that point to the cutter head - no discernible dish on the outfeed table - all checked with a veritas aluminium straight edge and feeler gauges.

[QUOTE
Specifically, the process of setting the outfeed table to the reference of the cutter head , .[/QUOTE]

I notice no-one answered this question?? I have the U.S . manual which specifically excludes any reference on how to adjust the out feed table. I can't even budge the lever after loosening the lock wheel. Which bit needs a strong hammer i 'm wondering!

Shouldn't the adjustment be possible without any under table fiddling?

Cheers

Loyd

You can only move the tables up and down without touching the grubs and bolts under the table. This is to adjust sag etc.

Originally Posted by Blazk

You can only move the tables up and down without touching the grubs and bolts under the table. This is to adjust sag etc.

Yup... that is my point really. The table won't move at all. The lever simply doesn't move. I guess there must be a locknut or something. Any ideas ??

Finally moved it......just needed about 300lbs on the lever