Use of Scrap Wood - Zero Clearance Inserts

[flashbacpt]

Happy Thanksgiving to one and all!
Because the cost of wood is expensive, I tend to keep every scrap of wood that I consider usable, with the hopes that someday I will use it.
Yesterday, I came across three very long pieces of 1/4 inch plywood, approximately 3 1/2 inches wide.
A while back I had ordered one Through Cut Insert #555518 from ShopSmith for an up coming project. I recalled an article in Wood Magazine explaining how to make inserts.
Basically, all that is needed is some double sided tape, a pencil, 1/4 inch drill bit, a flush trim router bit, and to make life easier, toss in a Hand Counter Sink (Lee Valley,#50K62.01), and a Transfer Punch Set (Lee Valley, #24K05.40).
The steps are simple:
Attach the Through Cut Insert, face down with the double sided tape to the plywood.

Take pencil and outline the Blade Guard Riving knife location.

Using the Transfer Punch Set, mark the location of the insert screws.

Trim the plywood close to the insert, so that you can effectively use a flush trim router bit to cut an exact copy using the insert as a template.

Separate the plywood, drill two 1/4 inch holes for screws, and then use the above Counter Sink to accommodate the holddown screws. I found the above countersink matches the angle of the screws exactly.

You are done! Now, if you are thru cutting, you will need to cut out the Riving Knife Saw blade Guard. I accomplished this quickly by drilling one small hole (width of the slot) at the rear of the previously marked Riving Guard, and used a scrollsaw to cut out the rest, giving an exact copy of the insert.

In a matter of a couple/three hours, I was able to make 14 blank inserts out of scrap plywood. Just remember to always outline the Saw Blade Riving guard location on all inserts. This gives you the option of having a total blank insert for DaDo work, or Through cut operation.

Another advantage gained is that you can mark (writing on the insert) each insert, listing the actual saw blade used, the depth of cut, etc., which in turn, should save you time in setting up operations.

Good Luck;)

[charlese]

Thank you flashbacpt! I have a stack of slight 1/4" poplar re-saw cutoffs from making louvers out of 3/4" stock. Now I know what to do with them. They might be a little thin, but can glue them together and then do some sanding if needed.

Now I'm glad most of these cutoffs survived my recent shop cleaning/purging.

This Forum is full of innovative thoughts and projects that can keep us going and going and..... What a wonderful Forum!

[flashbacpt]

Chuck,

Thank You, Glad I good help you! The 1/4 inch plywood that I used makes for a very level surface (level with the table) almost better than the actual SS insert.

You mentioned that your wood is slightly less than a 1/4 inch. My suggestion is that you go ahead and make one, and then mount it to your table. You might be pleasantly surprised in its fit.

If it is slightly recessed, place tape on the underside of the insert, along where it touches your table. One or two layers, just might do the trick, and save yourself a lot of sanding.

Good luck!
FlashbacPT

[paulmcohen]

Rather than go through all the trouble of cutting out the slot for the Riving Knife I use a Micro Splitter, they are cheap, easy to install and work great.

They take seconds to install and remove and they hold the wood against the fence with variable pressure (4 choices).

[flashbacpt]

I am aware of the micro splitters, and believe that they can be a very useful aid under certain conditions, having used them to cut down large sheets with a SkilSaw.

However, in this circumstance (Thru Cuts), I would never use them in place of the ShopSmith Saw Guard that includes the riving blade, and most important, the anti kick back feature.

I had a friend, since deceased, that was tired, after working all day, and needed to make one more cut on his table saw. He took a "shortcut", deciding not to take the time to set up his saw guard, etc.

His shortcut cost him the tip of one of his fingers, and a piece of pine enbedded in his bicep from the kickback. I just happened to arrive at his house seconds after this accident, and will never forget the scene.

I have a deep respect for machinery.................it's called FEAR! I'll take the five minutes to make the cutouts for the combination blade guard, riving knife, and anti kickback device.

[john]

I am also one of those that tries to work with saw guard and anti kickback prawls whenever I can. The combination guard/riving knife is one of the features I like about Shopsmith.

The post is appreciated and like Chuck I have quite a few 1/4" baltic birch cutoffs that might do the trick.

John

[paulmcohen]

There are lots of times when I can't use the guard, such as cutting narrow strips rather than using nothing I prefer the micro splitter with the Shopsmith fence straddler. The splitter keeps the wood against the fence and the straddler lets me safely push the work. The splitter also prevents kickback by preventing the blade from binding.

The Popular Woodworking review rates it 5 out of 5, I would love to see Popular Woodworking review the Shopsmith.

[james.miller]

I've used 1/4" and 1/2" Baltic Birch ply for inserts and also used 1/4" Melamine. With the 1/2" ply I route a recess around the outside of the underside using the metal insert as a guide to get them flush with the table surface, a lot of extra work but once in a while I have a few minutes that's not spoken for.

To mark the holes you can also clamp a metal insert face to face with the custom one then use a self centering center punch to mark the holes.

With Baltic Burch before cutting it through with the table saw blade I harden along the top center of the insert with very thin CA. It stops it from splintering out when the blade comes through.

I use my scroll saw to lengthen the back of the slot so the upper saw guard fits.

I use one insert for narrow kerf blades and another one for standard kerf blades.

With a quality plywood blade (HI ATB) and a zero clearance insert I get a very high quality of cut when cross cutting plywood.

[charlese]

Gosh! This has been a real good thread! All of the postings are appreciated and I'm still learning!

Although, I had seen mention of the micro splitter, I hadn't been to their website or heard any comments from anyone using them. Thanks for the link! One of these days, I may go that way.

In the meantime, I'll just keep using the old fashioned way that I've been using, for years, to cut thin strips for facings, Etc.
My shop garbage can is presently full with 1/16"x1/2" strips that were trimmed off of potential louvers, prior to routing. It I needed 1/16" strips these would be perfect.

Posting another technique for cutting thin strips seems appropriate, here's the old fashioned way:
1)Place the wider part of the workpiece against the fence and let the saw cut off the thin piece you want. Ahh!, you may say -
-what if I have to saw a workpiece that is already only 1/2" wide? For me there are at least 3 additional ways to handle this conundrum.
2) tape this narrow piece to a wider board and place the wider one next to the fence.
3) Go to the bandsaw. & - There is even another method-
4)place this piece together with others, side by side, (or face to face if you will) and run them as one piece through the thickness planer.

In any event, it seems to me that the Shopsmith upper guard and splitter is one of the best working units around. I use it for all ripping. If a board is too narrow to allow the fence straddler to easily slide between the fence and the guard - then it is too narrow (in my book) to make any narrower without using the above three methods.

[Bruce]

With Baltic Burch before cutting it through with the table saw blade I harden along the top center of the insert with very thin CA. It stops it from splintering out when the blade comes through.

Hey, that's a good idea.