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  • Resurfacing Table Saw Top

    This is something I've wanted to do for many years. the problem has been I haven't been able to find anyone that has a surface grinder big enough to do this.

    Well I finally found a shop that has a grinder with a magnetic chuck that is 120" long x 36" wide. This will do my 27" x 20" top with no problems. So, I sent the shop some pics so they could give me a ball park figure. I used the straightest thing I have in the shop as a reference bar to show the high spots, the 24" blade off my shear. It's flat and straight withing .0002. In doing so I accidentally dragged the bar from one end of the table to the other to look for discrepancies and noticed it was shaving the cast top. Then I thought, what if I were to hand scrape the top with the bar to take the curse out of it. I could go front to back, back to front and diagonally etc. to keep it as even as possible.
    The worst part is in the front where the bar is pictured. I placed some paper shims under each end of the bar to show the gap. The center is approx. .010 high, but it varies along the length of the top. I dragged the bar a few time in both directions to get some good scrap marks. You can see in the pics where they are.

    I hate to take this apart because it's a PIA as the arbor trunnions and screws all mount off the bottom of the table. The other thing is the two miter slots would have to be re-cut after grinding because they won't be deep enough, I would have to make special bars for my miter gages. The top is about 5/16" in thickness as far as I can tell. I don't know how it got this way, either is moved over time or just from wear. My uncle used to run a lot of junk lumber through it, lumber from concrete forms which is highly abrasive or a combination of both.

    What do you think??

    JL...............


    Click image for larger version

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    In this picture you can see the high spots. Due to the way they reflect I couldn't get all of them to show.

    Click image for larger version

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    This is what the bottom of the table looks like. This isn't mine but one I found a pic of. It's the same series top so I'm guessing its pretty close.


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  • #2
    Seems like a well built saw, and what look like cast iron extensions too!. From the 1950s or 1960s?
    Those high spots seem to be a bit oddly placed if just from wear.
    I know my 1970 Craftsman 10" table has seen a lot of abuse, from crusty wood to ceramic tiles. The table is not terribly high or low, and for any wood work I do, a few thousandths isn't going to be noticed in the results.
    Your idea of scraping to see if you can get the overall surface back to level. I think that might be what I'd try. Machining might leave you with more problems as you mentioned. Also consider the side extensions. Are they registered on pins? Is there enough adjustment to avoid a "catch" if you milled the table? How does the fence lock? Will a milled table impact that at all?

    In any case, that is a nice saw!
    S E Michigan

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    • #3
      Not to be discouraging, but...
      What about the wings?
      And do you really do woodworking with tolerances of > 0.010"?
      And why do you think the top is not liable to warp that much after you refinish it? I don't see multiple heavy ribbing such as you might find with a cast iron surface plate.
      And if the bar from the shear is that flattest thing you have, how do you know that it is true within 0.0002"? (Measured by someone else with better equipment?)

      I think of a table saw as kinda like a drill press - not accurate beyond a certain point, and 0.010" is probably pretty good. If you need more than that you start using old fashioned hand techniques (or maybe your machine tools). Of course, that's just me.
      "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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      • #4
        How does that .010 make a difference in your cuts?
        Location: Saskatoon, Saskatchewan, Canada

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        • #5
          Originally posted by OaklandGB View Post
          Seems like a well built saw, and what look like cast iron extensions too!. From the 1950s or 1960s?
          Those high spots seem to be a bit oddly placed if just from wear.
          I know my 1970 Craftsman 10" table has seen a lot of abuse, from crusty wood to ceramic tiles. The table is not terribly high or low, and for any wood work I do, a few thousandths isn't going to be noticed in the results.
          Your idea of scraping to see if you can get the overall surface back to level. I think that might be what I'd try. Machining might leave you with more problems as you mentioned. Also consider the side extensions. Are they registered on pins? Is there enough adjustment to avoid a "catch" if you milled the table? How does the fence lock? Will a milled table impact that at all?

          In any case, that is a nice saw!
          The extensions are not located with pins. They are just bolted up to the table with bolt holes that allow for plenty of adjustment. So that's not an issue.
          What would be an issue is that the sides of the saw and the extensions would have to be either ground or milled to ensure they are square to the top. Last thing I would want is to bolt up a side wing and fine that it pitches up.
          As you can see in the pic the side wing on the left actually pitches downward a bit. That hasn't proved to be a big issue unless I'm crosscutting longer boards.

          It is a nice saw. It was originally purchased by my grandfather is the mid 50's. It's been in the family for many years. I have the matching jointer also.

          JL....................
          Last edited by JoeLee; 11-21-2020, 12:41 PM.

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          • #6
            Originally posted by mickeyf View Post
            Not to be discouraging, but...
            What about the wings?
            And do you really do woodworking with tolerances of > 0.010"?
            And why do you think the top is not liable to warp that much after you refinish it? I don't see multiple heavy ribbing such as you might find with a cast iron surface plate.
            And if the bar from the shear is that flattest thing you have, how do you know that it is true within 0.0002"? (Measured by someone else with better equipment?)

            I think of a table saw as kinda like a drill press - not accurate beyond a certain point, and 0.010" is probably pretty good. If you need more than that you start using old fashioned hand techniques (or maybe your machine tools). Of course, that's just me.
            The wings are 8" wide and can be ground. So not a problem. And yes, I do hold some of my woodworking tolerances to better than .010 depending on the type of wood. Small piece usually aren't a problem, larger pieces that are effected by the tops inaccuracy are.

            About the top warping after grinding ??? That's a good question and I have thought about it. that's why I'm considering scraping it.

            The table doesn't have the heavy ribbing that you would see on a cast iron surface plate. That's probably one of the reasons it moved. Other thing is those two slots probably didn't help the stability either. I doubt that these castings were seasoned to relieve stresses either.

            I've checked the shear blade on my surface plate so I know that it's flat within the .0002

            JL.....................


            Last edited by JoeLee; 11-21-2020, 12:54 PM.

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            • #7
              Should be low in center if wear is the issue.

              Looks like a nightmare to set up on grinder to me. I bet the quote is toe curling.

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              • #8
                The issue I see is that when the table is flat by itself, with no external forces, that's great, but then you bolt it down to the frame of the saw. That bolting is going to cause warpage unless the frame is flat and the bolting points are all flat.

                The top is not nearly as rigid as a lathe bed, so it will not stay flat even if you make it flat by grinding, any issues with bolting will pull it "out"..

                If you really want it flat, you might have to skim the mounting bosses as well, and then possibly SHIM the mounting points to maintain flatness, and probably adjust the feet of the frame as well. I am not sure that "the game is worth the candle", it's a lot of work for something that likely makes little difference, for most saws with pressed metal frames.
                1601 2137 5683 1002 1437

                Keep eye on ball.
                Hashim Khan

                If you look closely at a digital signal, you find out it is really analog......

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                • #9
                  I agree, the risk here is that the top isn't naturally out like this. It may be but it's also equally possible that it is being pushed to crown like this by the trunnion assembly bolted from below. You may go to a lot of trouble and expense only to find that when you re-assemble it the same high spot is back again.

                  If you're keen enough to do this in the first place I'd say start by removing the wings, front and rear bars. Then double check the table with that one source of stress removed. If it's still got the high spot then remove the top and trunnion group from the box and double check in case it's the box. If the hump is still stable then loosen the trunnion assembly and check again. if things suddenly change then you might want to check on how the trunnion assemble fits to the mounting pads. There may be a nasty wracking in the assembly that is stressing the table.

                  If there is still a hump in the place and the trunnion assembly fits evenly and stress free into place then at least you have the saw broken down and ready to ship off to the guys that can do the job.
                  Chilliwack BC, Canada

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                  • #10
                    As for you guys saying that there's no need to work to .010". Well, that's right but it's also not right.

                    There may not be the need to work to some very specific value. But when you start playing with some wood working joints there very much is the need for very precise cuts to achieve the sort of fit that is needed and for the results to look good. And at those times the need to accurately split a fine pencil line or even a knife scribed line is needed.
                    Chilliwack BC, Canada

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                    • #11
                      Have you tried checking the table when it is not bolted down?
                      From the marks made by the shear blade, you could get it considerably better by yourself, and getting the blade re sharpened if you made it blunt would be much cheaper than a table regrind.
                      Last edited by old mart; 11-21-2020, 03:57 PM.

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                      • #12
                        Originally posted by BCRider View Post
                        As for you guys saying that there's no need to work to .010". Well, that's right but it's also not right.

                        There may not be the need to work to some very specific value. But when you start playing with some wood working joints there very much is the need for very precise cuts to achieve the sort of fit that is needed and for the results to look good. And at those times the need to accurately split a fine pencil line or even a knife scribed line is needed.
                        I'd still like to know what difference that .010 makes in a cut.
                        Location: Saskatoon, Saskatchewan, Canada

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                        • #13
                          But when you start playing with some wood working joints there very much is the need for very precise cuts to achieve the sort of fit that is needed and for the results to look good. And at those times the need to accurately split a fine pencil line or even a knife scribed line is needed.
                          I don't disagree with this at all, but I don't expect to get that from a table saw. If I want that precision then *maybe* a well adjusted jointer, but more likely sanding, hand scraping, or some other non-power tool process. Or the milling machine.
                          "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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                          • #14
                            For the wings to be flat to within a few thou, the sides of both the wings and table will have to be ground to within a very tight spec.
                            21" Royersford Excelsior CamelBack Drillpress Restoration
                            1943 Sidney 16x54 Lathe Restoration

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                            • #15
                              Originally posted by Arcane View Post

                              I'd still like to know what difference that .010 makes in a cut.
                              I have a saw that's similar in looks, and age. Mine is a contractor's model, several pay grades below this one. Similar design and trim make me think they're from the same factory. The table is also warped, bit it's low where Joe's is high. On rip cuts, it's not very critical, but when making miter cuts, like for a picture frame, it gets tough to make a nice job. In my case, I was getting a dish effect. Once I figured out what was happening, I was able to work around it to some effect. I'm pretty sure Dad never had any problems with this while he used it on construction job sites. He did high quality finish work, but used a high end miter box for trim work.
                              I cut it off twice; it's still too short
                              Oregon, USA

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