Sacrificial Top for Radial Arm Saw

[David Winer]

I have replaced the “used up” composite material top of my large radial arm saw with a 1” thick birch plywood top. This beauty loudly calls for a sacrificial top surface. My plan is to add a tempered masonite or thin plywood cover.

I am concerned about the possibility of the top layer not lying perfectly flat against the primary top. Here’s my plan: First attach a small area in the center with contact cement so the middle of the sacrificial cover is held against the main top; then attach the edges (out of the reach of the saw) with countersunk screws. When it comes time to replace the top, unscrew it and break loose the small cemented area.

Before doing this, is there a better way, or is a cemented center even necessary?

[David C. Roseman]

Screws and contact cement sounds like overkill, to me. If you do use contact cement for the center, I'd think it would have to be a very small amount indeed, to avoid creating its own bulge. And it may lift the surface veneer of your birch top on removal.

Over the years I've used either 1/4" lauan plywood and 1/4" tempered hardboard, tacked to the 1" MDF main table with a nail gun and 5/8" brads (strategically placed, of course). Both types of material have stayed plenty flat that way. I prefer the hardboard for its smoother surface.

The nail gun countersinks the brads fairly deeply. I don't use the saw to cut many odd angles, so the likelihood of hitting a brad head is pretty small, even if the blade is set deep enough to do so.

David

[jack forsberg]

you can always use brass screws/nails and not worry if the saw hits them. Not a problem for TCT saw blades to cut this metal brass or aluminium that why saw plate insert are made of them.

[david brum]

My sacrificial top is held with a bunch of brass brads. As Jack says, they are soft enough to cause no harm to your saw blade and they are reusable. My favorite top material has been 1/4" mdf. It's super flat and uniform thickness.

[Chris Rosenberger]

I use 1/4" maple plywood over my radial saw top. I put small beads of silicone caulking at the fence, around the edges & under the 90 degree blade cut line.
The silicone caulk keeps sawdust from getting between the saw table & plywood & making the surface uneven.
I then attached the plywood to the saw table with 5/8" brads. I have had the same piece of plywood on the saw for several years & it is still flat.

[HANK METZ]

I simply use wire brads to secure the top with, being mild steel even if hit with a sawtooth it yields readily. Most important is when I replace tops, I offset then from the rear fence to provide sawdust a means to travel down and away from the face. A washer spaces it out nicely:

270036

[Paul M Miller]

I'm still using the original table top from the 60's with no sacrificial top. Every year or so I fill all the kerfs with Bondo or Wood Filler, and give it a quick sanding.

[Paul Wunder]

Paul,

Brilliant idea. Too bad I didn't know that when I still had my RAS.

[Aaron Berk]

I used lots of carpet tape, and 3/4 mdf for my sacrificial top.

Works for me.

[Rick Potter]

270107270108Mine has a 1/4" tempered Masonite top, held on with small screws. Since I only crosscut with it, I have an easily replaceable 3"wide insert painted red which is also held down with screws. If you plan to do angles etc, the brass screws are the way to go. When it is time to redo the Masonite, just remove the screws, and use the top for a pattern, including where the screws go.

Rick Potter

[Sam Puhalovich]

Before you put that sub-top on ... look at the dust collection 'port' in Aaron Berks pictures. I recently adapted my saw to use the same scheme and was very pleased with the outcome. The chip collection went from about 75% to > 95% for most cuts. The scheme calls for a deep kerf trough to be cut into the top to allow the chips to follow their natural course. The original poster recommended cutting through the top ... I didn't find that necessary. Since you'll be covering the 1" material: I'd try a 1/4" wide x 1/2" deep 'tunnel' cut into the 1" material.

[Myk Rian]

I used brads to fasten my hardboard top. Just don't put them where the common angles will be cut.

[Howard Acheson]

Use double sided carpet tape in the center and along the area where the fence will be. The latter will keep out any sawdust which might want to raise the edge of the sacrificial cover. Use some small brass flat head wood screws around the perimeter. Brass won't hurt your blade if you run over it. However, you can easily plan the screw locations to stay away from the screw locations. Use 1/4" masonite, it lays flat and stays flat. Use you under table as a template for any penetrations.

[David Winer]

Thanks, everyone for all the ideas. All very helpful. After looking the posts over, the best solution in my situation is to fasten tapered hardboard board (Masonite) with brass fasteners wherever needed. It seems that there are numerous ways to add a sacrificial top simply--without a need to over-engineer it.

[Roy Turbett]

Wally Kunkle, aka "Mr. Sawdust" recommends against using masonite because he claims it tends to dull saw blades more quickly. I use 1/4" MDF and attach it with two sided carpet tape and brass brads.

[Joseph Tarantino]

Thanks, everyone for all the ideas. All very helpful. After looking the posts over, the best solution in my situation is to fasten tapered hardboard board (Masonite) with brass fasteners wherever needed. It seems that there are numerous ways to add a sacrificial top simply--without a need to over-engineer it.

5 screws through 1/4" MDF do the trick for me. dead flat, no cement. you want the sacrificial top to be easily removable.

[Greg Hines, MD]

I don't have a RAS any more, but when I was growing up, we did, with the old particleboard top. Filled the kerfs with epoxy from time to time, but it rarely needed much.

Doc

[John Lifer]

I'll be the first to say that I don't use anything to hold down the masonite sheet on my saw. No reason to as what I cut is above the masonite. But all my cuts are crosscut. If I was making angles there would be possible triangles that would be loose. I would then glue it down.

[Mike Wilkins]

Years ago I had a Ryobi radial arm saw. I used the Rick Potter method of routing an insert for the installation of a 1/4" Masonite insert, held down with brass screws. Since I only cut at 90deg there was no need to replace the entire top after performing angle cuts. That is why miter saws have replaceable inserts for the same reason.