Screeching and gnashing noises?

[Richard Hash]

Yeah, the screeching and gnashing (of teeth) noises are coming from me. I'm looking for suggestions as to how to "fix" ("mitigate" is probably a more accurate term) something I'm still irritated about.

I'm making a new router table top to hold an Incra Mast-R-Lift II. It's not my first one (I've made two before), and while I still can't really say exactly what went wrong, it's obvious the template used to route out the insert hole creeped. It's a 36"x28" top, made of two 3/4" MDF glued-up slabs, with 7/8" oak edging, laminated top and bottom. It's well-supported with "flatteners" on the bottom. I'm not a fan of rabbeted ledges, I'm a "cut the hole all the way thru" kind of guy, and just use plate-levelers (that way you never have to mess with dust settling on the ledges, or getting the rabbet depth right).

The problem I have is that my freshly cut out hole is about 0.070" off side-to-side (each direction)!! It's enough to really bug the living daylights out of me. It's not the templates fault (it's factory CNC machined, Mark Mueller from Incra tells me it's oversized by 0.020" side-to-side on purpose), the dang thing *has* to have moved on me while routing.

So what I've got is a sloppy hole. My options, as I see them are:

1. Bite the bullet and make a whole new top. Not on my fave list. Not something I want to think about (yet).
2. Figure out some way to shim it.

One of the (many) things that crossed my mind was to drill some horizontal holes into the sides of the cut-out hole and slathering some epoxy/JBWeld type stuff around the interior (the horizontal holes would be to help it get a "grab"), and then (more carefully!) re-rout out the opening. Is this a crazy idea?

Any better ideas? Trust me, nothing you can come up with is any crazier than things I've considered...

Still gritting my teeth,
Richard

[Chuck Nickerson]

How about drill some horizontal holes that are just pilot holes for screws. Then drive the screws just deep enough to occupy the slack space?
.05" is about the thickness of five playing cards. With a 32 tpi pitch screw that will be almost two turns back from a flush screw.

[Marion Smith]

How I would do it:
Re-cut your .07 oversize bore to 2-3" oversize.
Then, rout out the top layer of mdf 2-3" bigger than that.
Glue up another mdf sandwich, where one layer can be turned down to fit the thru bore, the other to fit the flange diameter. From here, you can either glue it in, or screw it in. Using screws makes it way easier to fab another insert should it ever get boogered up again. Then, set up your template and re-cut the bore how you like it.
Edit: Of course, screwing in the insert from the bottom saves you from ugly stuff on top.
If the visible line is another source of frustration, rout the top portion 1/8"-1/4" larger than the insert flange, fill the gap with a strikingly awesome contrasting color filler and sand flush. Then tell anyone who inquires about it that you designed it that way!

[Rick Johnston]

An epoxy paste called PC-woody. Made by a company called Protective Coatings. They also have other paste/putty epoxy on their site.

[glenn bradley]

Bondo, JB Weld or other epoxy product can be added and then re-machined. A strip of hardwood (or MDF for that matter) could be glued on to the offending edge and re-machined.

[Myk Rian]

Next time wrap several layers of tape around the router guide.

[Mike Heidrick]

I'd remake it if it bugged me that much. Seeing the rigged fix would bug me too.

[Walter Plummer]

Peel the laminate using lacquer thinner. Rabbit the top layer back. Glue in oak to match edge detail, laminate the top again and cut hole again. Make sure your bit is concentric with the router guide. Sometimes they are not and you can over size that way. good luck and let us know which way you go.

[Mike Goetzke]

Could you get some aluminum (stainless?) wide shim type material to line the opening?

Mike

[Richard Hash]

If there is a next time, this will *definitely* be on my check-list. That's exactly what I did the last time, so I could sneak up on the right amount of 'tight', but like a moron, this time I thought "what could possibly go wrong?". And life answered my question ;-)

> Next time wrap several layers of tape around the router guide.

[ian maybury]

Polyester car body filler (bondo in US speak i think) might be easier to machine, sand and work than an epoxy based filler...

As Walter re-laminating the top (the bottom too if you're picky) would open the way to a multitude of fix up options. It'd be necessary to clean the MDF back to a smooth original surface though - it wouldn't take much of a bump or ridge under the new laminate to knock it enough out of flat to matter...

[Richard Hash]

Well thanks to everyone for all the suggestions. I was finally able to get a bit of free time to fix my blunder. I ended up using JB-Weld (mostly because I have big tubes of it handy), and discovered it it routes quite nicely.
2.jpg

After re-routing the plate hole, things fit *much* better:
4.jpg

I tried telling my wife the gray trim line was a completely planned artistic feature, but that dog didn't hunt since she had overheard a great deal of the original gnashing of teeth.

New top - ready to go:
5.jpg
6a.jpg