zero clearance insert for radial arm saw

[Cooler]

A few years back I got a recall on my Sears Craftsman radial arm saw.  It included a new blade guard and a new table top.  The table top is still in the carton.  The blade guard (a good fix--the old one would not accommodate a dado head), is on the machine.

The table top is one inch thick.  The old one is badly scarred and the cut is no longer clean on the bottom of the work.  

I was thinking of making a new one from two thicknesses of ½" MDF glued to the 1" thickness.  A section about 4" wide (2" on either side of the blade) would be screwed in and replaceable.  

Question:  

1.  Has any one made a replaceable insert for their RAS.
2.  Is this the best way to go about it?
3.  Would 3/4" laminated to 1/4" MDF be a better approach?

I always cut a little into the surface of the table top.  I have no idea why there are so many different score marks (over a range of 3/4").  I would think that there would only be a single score line.

[MarkSingleton]

I made one years back out of 3/4" particle board with a top layer of 1/4" hardboard,
used a spray on adhesive, and it has held up pretty well. Never saw a need for an
insert. The table has gotten chewed up a bit over time, as expected but if I do my
part and keep the saw adjusted correctly, it cuts just fine.

One of these days when I have nothing else pressing, I suppose I am due to make
a new one, but the old one keeps working as is.

[fredhargis]

The more common approach is to have a sacrificial top surface, 1/4" MDF or such. I suspect that's because while some folks only cut 90˚, the majority swing the arm back and forth...putting saw kerfs all over the top. Still, if you wanted a replaceable strip you could it. Put dovetail edges on a 2" long piece that spans the front to back dimension, and put slide it into place. I use the sacrifical top.

[TDKPE]

And since the blade is to the left of center, or is on my Delta 12" at least, when the top is too scored you can just peel it off, add a little more sticky spray, and put it on 'backwards' for a whole nuther fresh kerf groove.

[jteneyck]

I made a ZCI for my RAS table.  It's a piece of oak about 2" wide and screwed in with brass screws on both sides of center.  After that got chewed up I realized the easier solution was to just fill the ragged kerf with Bondo and scrap it level after it cured.  That's what I've been doing for the past 10 years and it holds up as well as wood.  When I need a premo cut, though, I put a piece of Masonite down, as someone mentioned, and move it to fresh material for every cut.    

John

[srv52761]

I was thinking of making a new one from two thicknesses of ½" MDF glued to the 1" thickness.  A section about 4" wide (2" on either side of the blade) would be screwed in and replaceable.  

Question:  

1.  Has any one made a replaceable insert for their RAS.
2.  Is this the best way to go about it?
3.  Would 3/4" laminated to 1/4" MDF be a better 
I always cut a little into the surface of the table top.  I have no idea why there are so many different score marks (over a range of 3/4").  I would think that there would only be a single score line.

Just as your work registers against the table on your table saw and router table for accuracy, so too does your work register on your RAS table.

The classic Mr. Sawdust table
Not a zci table, but a zci fence
After spending time to get a relatively flat table, many use a sacrificial top and replace it as needed.

https://m.youtube.com/watch?v=6TMBT45g_qg
edit: I used 1/2" mdf as a sacrificial top instead of 1/4" stuff. To attach the sacrificial top, I too used screws, but as another mentioned, use brass.
You see him drill pilot holes for the screws. I would suggest after drilling the pilot holes, remove the sac top and countersink the pilot holes on the table and the underside of the sac top; as you drive the screws you will raise fibers.  The countersink gives the fibers somewhere to go.You can see his sac top is not quite flush.

https://m.youtube.com/watch?v=Q1cc-_vPT0w


https://m.youtube.com/watch?v=u5mljNC-4zs

[Pirate]

When mine wears more, I plan on fixing, like I fix the ts insert.
Bondo

[Stwood_]

My radial saw is longer. Sold.....took years to find a sucker.
 

Anyhow, I just 18ga nailed 1/4 ply scrap on both sides of the blade. All I did with it was straight cutoffs, so no worries about hitting those gun nails.