OK. How flat does it have to be?

I built my own top for my router table and it has a slight sag in it. At its worst it is .016"

I'm guessing this might be a problem. Some shimming from underneath when the top is attached might help.

I know we would like our surfaces to be dead flat, but how flat does it have to be? Time to start over?

Nah, I'd do just what you said...shim from underneath. You might need to make sure the top is held in place securely around the sag so that you only shim the low spot.
I've never checked my home built RT top. Now I have something to do tomorrow that doesn't cost money.... Jim.

It will cause a .016" snipe in your work. Now they question is how many strokes with 150 grit sandpaper will it take to remove .016"?

Chuck Thoits said:

It will cause a .016" snipe in your work. Now they question is how many strokes with 150 grit sandpaper will it take to remove .016"?

Click to expand...

I shimmed with masking tape. Took 3 or 4 tries (screwing down, checking unscrewing, shimming and repeat) and has been flat ever since.

well .016 is rather large to deal with for some
applications, some not so with some others.

Can you put up a picture of the table you made
maybe that will give us more clues/fixes

I read your thread about the forgotton rounded corner

I once had a router mount that flex'd, because the plate material I
used was just to thin , my last one is made from 3/4" thick
arborite (no flex there ) and have been using it for years
in many different set ups.

side note: Jim , Love the Avatar, great thing your doing for those
hounds down in Texas, just wish ya was closer
these are my kids


picture taken a long time ago.

but the big guy will be heading to heaven this week, he got up
to 17 years old , but can't walk anymore, he's given up ,and wants to go
it seems ,as always we wish we had more time for them.
great thing your doing
up here, the irish setter is a very rare dog to see.

WOW! 17 yo on an Irish is great! We've not been able to get past about 13 or so. Yes, no matter how many years, it's always too short. Is the one laying down in the foreground an Irish Golden mix? Hair doesn't look purely Golden. If it wasn't for that, I'd say a red Golden.
My avatar is the only girl, Cory, out of the first litter we bred back in 1995. There were 6 in the litter. We bred Cory and had one pup. Taz is 9 1/2 and lives up to her name. Maybe she will be the one we get over 14 yo. Jim.

hey thanks for commenting

The gold dog is a English Golden Ret, she's also 17 now
her mother was more red , when I ordered the dog and
had it shipped over .

she was breed with Micky , my Irish Setter , what ya get is a
totally copper dog , copper eyes,nails ,black nose
with the best traits from both dogs..

When I did my research , noting the IS is the only real red
dog and the goldens have a hidden red gene .
breeding a IS with any other color dog will result in Black

she is half way in between both the other two
I had 43 of them , through 4 litters , I keep the first one
out , to show the evential color the dog would turn
I had 11 repeat buyers, the little one is 11 now.

all the female looked more setter, and all the males looked Golden Ret in their faces
here is a picture the last time some boys cam over for a weekend visit

OK - in an effort to get this thread back on topic

So, if I firmly attach the outside of the table to the case I should be able to shim under the inner supports to eliminate the sag?

yes rennie, that should do it if you can anchor to your top sufficiently..

I have a mdf top on my table that also sagged. I put a support just in front and back of the insert. Than shimmed to get the top flat. I had to bolt the outer corners down so they wouldn't lift with the shims. I had about an 1/8" sag. So far it has stayed flat. I also found that my insert wasn't flat. I used sandpaper on a granite block and gat it flat. I used business cards for shims.