Router table flatness problem...

I built a router table (Router Magic version) two years ago. The table was of laminated plywood with the high centers turned in then edged with oak, then plastic laminate covered. It was not perfectly flat at the time of building but it has gotten worse. The middle area where the router hangs that is unsupported is about 16" square give or take a couple of inches. There is no router plate as the router is permanently mounted (screwed) to the table. The whole thing has sagged some. A good portion of the sag is in the unsupported area as would be expected. The maximum sag is about .035" which might not sound like a lot but see what it does to coping and sticking cuts!

I discovered the problem "anew" when I finished a sled to groove and dado panels. On a 6" width I have to really apply pressure to stay within ten or twenty thou from one side to the other. It is worse on a wider piece. On shelf dados this is no serious thing, but I need to cut some sliding dovetails over about a 10" distance and that will be a problem.

I NEED to flatten this table! Some say that this is the reason for cast iron. Others say go to steel like Lee Valley, but their table has a .030" reverse crown and would complicate things the other way. I bought a piece of angle iron, but the worst (lowest) place is right in front of the router which would mean partially blocking access to change bits. It would be hard to reinforce and raise that area, if possible, without making bit changes difficult.

I've thought of shimming the cabinet dividers to force the table up in these areas, if that would work. But it would still leave the unsupported area in the middle... unsuported. And how long would it take for the table to sag back to the shims?

Should I try sanding the laminate down on top and see what's left? Should I strip the laminate, which might be tough, plane/sand and relaminate? Does anyone have a "great idea" or been through this before?

I'm at a loss on how to proceed. Any ideas are appreciated. I am to the point that I don't mind spending a few dollars if I can get a table large and flat enough.

David

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Originally Posted by David

I'm at a loss on how to proceed. Any ideas are appreciated. I am to the point that I don't mind spending a few dollars if I can get a table large and flat enough.

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Dave:
When I built my cabinet I set up the top so that the entire top hinges at the back of the cabinet.The LV metal insert is supported by the two drawer pillars as well.
Changing bits involves either lifting the table(at the front) to access the router or through the top with an angled open end wrench.

Here's a couple of pictures to give you some food for thought.
p.s. Where did you get the info about the LV top being convexed?
Just curious.

Bob

Hi Bob,

The Router Magic table which I built hinges at the back of the entire table. With my massive fence that puppy can get heavy, but it works well for bit changes. BUT a piece of angle iron in front of the router on the bottom would block most access. That was why I mentioned that.

After hearing that the table were convex online, I went to Woodcraft in Tulsa OK and checked 3 that they had. All were convex by around .020". I emailed Lee Valley and they acknowledged that that was by design to either allow for sag or prevent it. I can't remember which. But they did say they were made that way. Most online posts said that the convex (-ness, -ity? ;-) ) never comes out no matter how heavy the router. Is yours flat? I like their idea and would likely buy one to use as an insert as you did if I can get a flat one. It will add a chunk of weight if I keep hinging the entire top. How did you hinge the back? Your pics may show, I'll look again.

David

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Originally Posted by Bob Oswin

Dave:
When I built my cabinet I set up the top so that the entire top hinges at the back of the cabinet.The LV metal insert is supported by the two drawer pillars as well.
Changing bits involves either lifting the table(at the front) to access the router or through the top with an angled open end wrench.

Here's a couple of pictures to give you some food for thought.
p.s. Where did you get the info about the LV top being convexed?
Just curious.

Bob

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Originally Posted by David Rose

Hi Bob,


Is yours flat? I like thier idea and would likely buy one to use as an insert as you did if I can get a flat one. It will add a chunk of weight if I keep hinging the entire top. How did you hinge the back? Your pics may show, I'll look again.

David

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Dave : Here's a pic of mine with a 1/2" x 1-1/2 milled steel bar across it.
I can't get a business card in anywhere. As matter of fact I can hardly see any daylight. which is way beyond where my meager skills drop off.
The router is Hitachi and stays mounted most of the time.

The steel LV plate is inset in a 3/4" plywood top which is resting on the supports for the drawers. I have four set screws, -one at each corner of the steel table to level it to the arborite top. My fence slides along the outside of the steel table and allows me to lift the whole works up on stanchions to play with the router. Most time I just use the angled wrench through the top. I can lift the whole table and router out and put it on the Lee Valley bench mount for taking to the lake or another location.
So I have two tables.
One for the shop and one for "house calls" , Ha Ha. :D

Because I follow the guys on Router workshop, I am not much of a fan of precision fences other than wanting them to be straight and sturdy.
I hope I haven't confused you with this set up
E-mail me if you need more info. I hate to monopolize the forum with my projects.

Best Regards
Bob

David,

I've got the Lee Valley tabletop, too. With the DW625 hanging in it, I can't detect any remaining convexity.

I like their system a lot, but I'm a newbie.

- Ed

Thanks Bob and Ed. I'm going to check with Lee Valley again. That would close to flatten my table.

David

Haven't done this myself, but have thought about it in the past, if I ever have the room to build a stand-alone router table. Now, this may be way, WAY out in left field, so please, don't flame me for suggesting it. What I've though of doing is to take the angle iron idea and use it...sort of. Instead of plain angle iron, which usually varies in thickness from the edge to the inside angle, use something which is machined with flat, equal-thickness dimensions on both, the outside and inside of the angle. I suppose one could even use some heavier extruded aluminum angle, which typically is consistent throughout. At any rate, instead of just slapping the thing up in front or on either side of the router, where it might get in the way, cut a dado the length of your angle and bury one of the angle legs into it. Then drill and attach the other leg to the bottom of the table. I'm NOT an engineer, by any stretch of the imagination, but it seems to me that a method like that would still give the rigidity and support as it would being flipped the other way around. Hey, never know...Might even work. :cool:

He he... waayyyy out... flame flame... :D

Actually, I had considered doing that when I bought the angle iron. So flame "me", huh? :-) I checked some of what the Borg had and 1 & 1/4" seemed to be the smallest that had much rigidity. If the entire leg was buried in the table, it would be well over 1/2 way through. My concern, even with it epoxied in, was that it would make another place for the table to give. With that large an area the whole thing needs a lot of integrity with itself. Am I making sense? Inletting that leg would almost split off a section, in this case the front.

I remember someone on the Pond saying that he built several tables and had never seen a wooden one completely flat. He ended up using a table saw wing of cast iron or something like that. I suspect machined metal sheet is the answer.

I wrote Lee Valley to see what they say. Their specs do say that the table crown will pull out with an 8 pound router. It seems a little pricey at $150, but it comes with a quick clamp system for the router. And if it will get my faulty cuts cured, it will be worth it.

Remember that I did ask for any ideas. I think your idea would be great incorporated with a frame that went all the way around the table so all pieces had good support. And I am not at all sure that it would not work stand alone. It just might.

David

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Originally Posted by John Miliunas

Haven't done this myself, but have thought about it in the past, if I ever have the room to build a stand-alone router table. Now, this may be way, WAY out in left field, so please, don't flame me for suggesting it. What I've though of doing is to take the angle iron idea and use it...sort of. Instead of plain angle iron, which usually varies in thickness from the edge to the inside angle, use something which is machined with flat, equal-thickness dimensions on both, the outside and inside of the angle. I suppose one could even use some heavier extruded aluminum angle, which typically is consistent throughout. At any rate, instead of just slapping the thing up in front or on either side of the router, where it might get in the way, cut a dado the length of your angle and bury one of the angle legs into it. Then drill and attach the other leg to the bottom of the table. I'm NOT an engineer, by any stretch of the imagination, but it seems to me that a method like that would still give the rigidity and support as it would being flipped the other way around. Hey, never know...Might even work. :cool:

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Originally Posted by David Rose

I remember someone on the Pond saying that he built several tables and had never seen a wooden one completely flat. He ended up using a table saw wing of cast iron or something like that. I suspect machined metal sheet is the answer.
David

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Dave, like I said, it's just an idea. I guess it would largely depend on the angle's depth vs. thickness of the table.

Now, for the table saw wing: Last year, when I was looking to buy an actual cast iron wing for my Delta Contractor TS, (lots of $$) someone mentioned a less expensive unit at Harbor Freight. Same size as the OEM wing, matched up pretty nicely to my existing main table, @$50.00 AND, it already has a place for the router! Complete with a hold-down clamping system for the router and one insert for the bit opening. I found that 1/8" masonite with a couple layers of duck tape will bring a homemade insert up even with the table top. In case you haven't figured out by now, that's what I'm using for my router table, primarily due to space constrictions. I'm presently just using a straight fence clamped to the table, but the table itself has a number of threaded holes in it, which I'm sure a guy could adapt for a custom made fence. Hey, just a suggestion.... :cool:

David,

I have the whole Bench Dog setup that I bought at a show. However, I was looking at the Sommerfeld setup with the phenolic table top with the router attached directly to the top just like in your setup minus the hinged top which would be unnecessary. You might want to look into this setup as it appears to be ideal. I believe that you can buy just the top ans insert rings only. You can talk to Marc Sommerfeld directly and he is very helpful. The reason I didn't go for it myself was the fact that I already had a Freud router and they didn't have a bent wrench for bit changes. Obviously you would have to have a router that supports his bent wrench system. Otherwise, I would be using that setup right now. The LV metal plate seems like a good choice as well. Hope you find a solution to your problem.....Danny

It appears that style of Sommerfeld table is discontinued. They have one with an insert plate only. Ugh!

David

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Originally Posted by dhaber

David,

I have the whole Bench Dog setup that I bought at a show. However, I was looking at the Sommerfeld setup with the phenolic table top with the router attached directly to the top just like in your setup minus the hinged top which would be unnecessary. You might want to look into this setup as it appears to be ideal. I believe that you can buy just the top ans insert rings only. You can talk to Marc Sommerfeld directly and he is very helpful. The reason I didn't go for it myself was the fact that I already had a Freud router and they didn't have a bent wrench for bit changes. Obviously you would have to have a router that supports his bent wrench system. Otherwise, I would be using that setup right now. The LV metal plate seems like a good choice as well. Hope you find a solution to your problem.....Danny

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