Pattern making/copying

[Chuck Pickering]

I am having a devil of a time trying to make a zero clearance insert. I guess it's my general lack of router experience giving me grief.
I have an old Craftsman 113-xxxxxx table saw. It has the thin .090" thick insert. I am trying to make /practice making insert blanks with my home made router table and a flush trim bit. I had made 2 inserts from 1/4" thick laminate flooring. I user my pattern bit to copy the aluminum OEM insert, and then using a rabbit bit, undercut the laminate so the insert fir flush in the saw table. Had a problem with the router bit pulling out of the chuck(chuck was not properly tightened) and ruined the first 2. If I had installed a 8" saw blade to cut the initial arc in the blank, I wouldn't have destroyed them.
So, managed to make 2 more blanks from laminate flooring and 2 from a scrap piece of Masonite. Had a time getting my router adjusted to the correct depth to follow the patterns. Rather than struggle adjusting the router height to the OEM insert, I used the laminate blanks as the pattern for the thinner Masonite.
Had issues with the double stick tape also. Lowe's had 2 types of double stick tape, a thick rubbery one that was labeled 30# strength, and a clear one that was labeled 5# strength. I bought he rubbery one, I think I should have got the lighter one. I had a difficult time getting the patterns off the blanks without breaking them, but reusing the pattern with the same tape allowed the pattern to slip on the blank. Destroyed a blank that way...
I will save one of each type blank for further patterns(all out of material to make any more). I will also go back and get the lighter tape, and some more material for blank inserts.
Any tricks I'm missing for setting up the pattern on the roughed out blank?
I set the blank and pattern on the saw table, plus a couple of shims of thick tablet cardboard to adjust the plunge of the router for depth to get the bearing to ride on the pattern. Router must be removed from the table to adjust... Someday I'll have a router with a height adjust that can be accessed while in the table!

Chuck

[John Lankers]

I usually get good results when cutting the blank as close to the layout line as possible on the bandsaw and then use a large diameter pattern bit in the router. I use a 1 1/2" rabbeting bit with a 1 1/2" bearing and still try to take a very light cut, especially in endgrain or when cutting against the grain. I can not recommend doing it but making a climb cut sometimes works best. There is still a small chance for the work piece to explode as happened to me last week when I made drawer pulls on the router table.
Using an edgesander instead of the router would give you much better control if that's an option.

[Andy Giddings]

Could you put the router on an insert plate and drop that into your table? That way you can at least pop out the insert and router together, adjust for height then drop them back into the table? Or even mount the router on a board so that you have access to the underside to change height. Having to dismount the router every time to change the height is going to get old very quickly. You could also build a simple lift. There are lots of YouTube videos such as this one https://www.youtube.com/watch?v=diAg_uZlb2s

You're correct on the tape - look for double sided carpet tape. It's thin and plenty strong enough. If you don't want to use tape there are plenty of other ways to mount the pattern to the blank - screws, hot melt adhesive to name two

I can't see that you are doing anything wrong, just that your setup is making life difficult for you and you are learning by doing

[Chuck Pickering]

Thanks, Andy for the positive reinforcement. My router is on a plate, a piece of Lexan. I'll try again with the carpet tape. I'm also going to get some thin quality ply for the inserts. Also need some good ply for a sled and box joint jig.

Chuck

[Martin Wasner]

I mark them out, rough cut them close on the bandsaw, then use the edge sander to get them to size.

[Myk Rian]

By 1/4" flooring, I'm going to assume Luan. The second worse material to use.
Cardboard being the first.

[Andy Giddings]

Just pointing out that sanding would help with the profiling of the blank, but the OP will still need to form the rebate somehow

[pat warner]

Double sided tape, (any tape for that matter) is a temporary adhesive.
As such you never know when it might release the work. It is very likely to fail under high stress
as when routing end grain.
Would abandon that. Rather, screw (your blank) to the master template.
And screw the sandwich to something else. Then use your hand router. Table routing is far more riskier (to fingers & the work) with a work piece you can't hold on too.

[Bradley Gray]

I use the same method as Martin - band saw and sander.

This thing doesn't need to hold water, just sit flush and not move.

[Chuck Pickering]

By 1/4" flooring, I'm going to assume Luan. The second worse material to use.
Cardboard being the first.

Not Luan, laminate, on mdf.

Chuck

[Bill Conerly]

I trace the pattern onto my material, then cut outside the line with saber saw, then sand to fit. Your method will take less time once you get the hang of it, but I cranked out 4 inserts in less time than it would have taken me to learn how. I guess it all depends on what you want to spend your time learning.

[Myk Rian]

What I have done is use 1/2" BB ply. I'll get the outside shaped, then use the router table to undercut around the edge where needed to fit it in the hole.