Delta DJ20 Fence Flatness?

[Ned Ladner]

Does anyone know what the flatness tolerance is for the Delta DJ20 jointer. How about specifications from other DJ20 parallelogram jointer clones?

[michael case]

The DJ jointer clone is the Grizzly G0490. The G0490 has superb tables and fence. They are within a couple to three thousandths. Grizzly has made a very impressive showing with this jointer. These Grizz jointers are famous for their flatness and I don't doubt are flatter than the Deltas. How much is your DJ 20 out of true and where?

[Ned Ladner]

Just wanted to bump this post to the top one more time to see of anyone can answer. Thanks in advance for your input.

Does anyone know what the flatness tolerance is for the Delta DJ20 jointer. How about specifications from other DJ20 parallelogram jointer clones?

[Dan Friedrichs]

Ned, I had a DJ-20 once, and thought I read in the manual that the tolerance was 0.008". I might be confused and/or making that up, though.

That said, a 0.008" dip on the infeed would be entirely different than, say, a 0.005" dip that was a few inches long after the cutterhead. Are you having some problem that you think is related to table/fence flatness?

[glenn bradley]

What does Delta say? A call might help. An email will be answered in a couple weeks in my experience. My G0490X had a .006" dip IIRC. It was cheerfully replaced with one that I think I found a .003" spot on. Certainly acceptable to me. YMMV.

You will hear people comment that a dip in the fence on a jointer is not a problem. I'm not sure how they use their jointers but I need my tables flat and my fence reliable at 90 as well as other angles. An untrue fence surface while running a 22.5* edge on a 24" long piece is definitely a problem. What are the symptoms of your problem?

[Rick Pettit]

I have a dj20 and I have the manual for it. Do you have the manual? I don't know if the tolerances are listed. I am at work now and can't look for you. I had trouble with the outfeed table on mine. There are no adjustments for this so I had to shim the table.

[Dan Friedrichs]

I had trouble with the outfeed table on mine. There are no adjustments for this so I had to shim the table.

Isn't the outfeed sitting on eccentric bushings?

[Ned Ladner]

Ned, I had a DJ-20 once, and thought I read in the manual that the tolerance was 0.008". I might be confused and/or making that up, though.

That said, a 0.008" dip on the infeed would be entirely different than, say, a 0.005" dip that was a few inches long after the cutterhead. Are you having some problem that you think is related to table/fence flatness?
I've found documentation stating .008" on the tables but nothing for the fence. My fence has a .015" dip. Not sure if that's an issue or not.

[Josiah Bartlett]

Most jointer fences tend to have terrible tolerances. Twist is much worse than bow or simple flatness issues, though. One way to get around it is to face the fence with a stable piece of wood and then joint the fence (the wooden face, of course).

[Pete Bradley]

What problem are you seeing? For edge jointing a few thousandths in the fence will not be measurable at the finished edge.

[David Weaver]

I have a buddy with a DJ-20, a taiwanese one, probably 6 or 8 years old.

Its tables are .002 out of flat (they are VERY flat), but the fence casting has a twist in it, enough so that if it's square at the front, it's not at the back, and if it's square at the back, it isn't at the front. I've heard him lament the cost of a new casting, and he basically gets free machining services, but he hasn't done anything about it yet. twist over its length is probably measured in hudredths and not thousandths.

The tables are parallel to a 48 inch starrett straight edge, so it isn't the tables.

[Barry Richardson]

I have a DJ20 at home and I use one at work as well. They both have a twist in the fence, they must not put as much care into them, I just kinda deal with it...

[Rick Pettit]

You know I see the same thing when I look at the jointer but the manual does not explain how to adjust the bushings and after an hour of trying to figure it out myself I found it easier to just shim the whole outfeed table. Tell me how to adjust the eccentric bushings please.

[Frederick Rowe]

Rick - Try this link.

http://www.happywoodworking.com/DJ20adjustments.html

Here's the original manual - photos are better.

http://www.woodwrecker.com/woodworking/manuals/Delta37-350.pdf

[David Eisan]

Hello there,

Since I manage a tool store, let me pipe up here.

How does the tool work? That is the only metric that matters.

When you edge joint two boards and put them side by each, is there a gap?

Put away your metal working tools and test the machine as intended. :)

Boy do I wish I could speak that plainly to my own customers.... :)

David - Tool Guy

[Clint Olver]

Put away your metal working tools and test the machine as intended. :)

Boy do I wish I could speak that plainly to my own customers.... :)

David - Tool Guy


Hmmm... I thought you did!:D


For the record, I have a DJ-20 that I bought from Dave. I think the fence is a little warped, but the wood seems unaffected.

C

[Dan Friedrichs]

You know I see the same thing when I look at the jointer but the manual does not explain how to adjust the bushings and after an hour of trying to figure it out myself I found it easier to just shim the whole outfeed table. Tell me how to adjust the eccentric bushings please.

The link Frederick gave you explains it well. But it's really easy - there are TWO set screws holding each bushing tight (one on top of another - so remove one, then remove the second one). Then just twist the bushing with a spanner wrench.

[glenn bradley]

Isn't the outfeed sitting on eccentric bushings?Yes and they make this adjustment fairly straight forward. Don't forget to back off your maximum travel stop (if present on the DJ-20, it is on the Griz 490) before trying to do your alignment.

[david brum]

I have successfully pulled the twist out of a jointer fence by shimming behind the fence bracket. This was done on a Palmgren cast iron bench-top jointer where there were four bolts attaching the fence to the bracket. Not sure how your Delta is set up, but might be worth looking into. Cast iron bends and twists pretty easily in my experience. John White at FWW actually tells how to take the droop out of a jointer bed by carefully jumping on it. I'm not saying to jump on your fence, just that CI is pretty soft stuff.

[Chip Lindley]

My fence has a .015" dip. Not sure if that's an issue or not.




How does the tool work? That is the only metric that matters.
When you edge joint two boards and put them side by each, is there a gap?

David - Tool Guy

David is taking you to task Ned. .015" may seem like a lot, but all depends on how it affects your ability to joint a square edge on a board. Under some circumstances, a jointer fence with a .015" dip, would have little or no effect on the accuracy of a 90 degree edge. A slight bow, either in or out, would not affect edge jointing. As long as the fence is perpendicular to the tables over the cutterhead, accuracy should be perserved.

Twist in the fence would be quite another thing. Winding sticks can be used to detect twist visible to the naked eye. But, if twist amounted to only .015" variance from one end of the fence to the other, it still should be usable for edge jointing. After all, wood flexes a bit also when held against the fence; unless you are jointing very short or very thick boards.

[Alan Schaffter]

Since no one has mentioned it, I'll keep this thread going with another point.

I strongly recommend against measuring, judging, or attempting to correct the flatness of a DJ-20 or any jointer fence using a square on the table. If your tables are not perfectly co-planer, flat, and perpendicular to your fence, the fence may look warped. You may think your tables are ok, but if they are not and you attempt to fix a "warped" fence by bending or grinding it, you now have created a problem that did not exist before!!

Since you could have problems with both fence and tables, the only ways to tell and be certain is to remove the fence and check it with winding sticks or a precision straight edge, or take it to a shop. Depending on direction of twist, a warped fence will show up as a gap or bump between two diagonal corners. If the fence is warped in two directions, there could be a bump or gap between both sets of diagonal corners. You should also test for flatness of the fence by running the straightedge near and parallel to the top and bottom edges.

[Rick Pettit]

Well guys it looks like the adjustment is made to the infeed table. It has been so long since I corrected my parallel problem that I can't remember if I looked at that or not. I would like to think I did. Anyway I shimmed the whole outfeed table with some sheet copper and have not needed to make anymore adjustments for three years. I would like to do it the correct way but I hate undoing something that is working fine. I don't know I'll have to think on it. Thanks for the information though.

[David Weaver]

Since you could have problems with both fence and tables,

Certainly hope that's not the case.

With the machine a buddy of mine has, the tables are in parallel planes, or however you'd put it geometrically. That's pretty easily checked if you have a high quality straight edge, some feelers and the tables themselves are very close to flat. But, as you say, it's very important to make sure that there is only one variable (the fence) by making sure it isn't the tables.

On his, it's clearly the fence, and to the point of the first post in this branch of the tree, I don't find anything wrong with checking a machine to see if it's within the manufacturer's specs. You've paid the price for the machine to get those specs, and figuring out that they affect the function much later just makes for a bad situation. In the case of the buddy's machine, it is bad enough to affect the squareness of pieces that are not tall - which is especially sucky if you're using them to support a mitered skirt on casework or something of that sort.