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How flat should my TS be? Seeing some gaps with a straight edge

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Forum topic by LucasWoods posted 12-24-2016 06:41 AM 1499 views 0 times favorited 10 replies Add to Favorites Watch
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LucasWoods

332 posts in 1168 days


12-24-2016 06:41 AM

So I am finally tearing apart a G1022 TS I got recently (free) I got the wings off so I decided to check how flat the surface was. I am seeing all through the surface between the two miter slots a 1/32 gap. Is this something to be worried about? It seems that from the miter slots out to the edge is a bit raised than the center of the TS.

If the 1/32 gap is an issue how hard would it be to take some sandpaper to the edges of the TS?

-- Colorado Springs, CO


10 replies so far

View mike02130's profile

mike02130

167 posts in 507 days


#1 posted 12-24-2016 11:10 AM

Don’t worry about it.

-- Google first, search forums second, ask questions later.

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knotscott

7784 posts in 3210 days


#2 posted 12-24-2016 12:31 PM

It’d take a significant deviation in just the right place to actually change the outcome of the cuts. If the cuts are good, don’t even measure the table flatness.

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

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LucasWoods

332 posts in 1168 days


#3 posted 12-24-2016 02:14 PM

Thanks all!

-- Colorado Springs, CO

View JBrow's profile

JBrow

1273 posts in 755 days


#4 posted 12-24-2016 02:35 PM

LucasWoods,

Flattening the table now, with the saw disassembled would be the way to go if you want to reduce cutting errors. However, before going in that direction, it would be important to ensure your straight edge is indeed straight. It may also be worthwhile to re-install the wings (which I assume are cast iron) and re-measure. The wings should be adjusted low compared to the main table so the flatness measure can be made without the wings interfering. My thought is that the heavy wings may impart enough downward deflection in the top to reduce the error (although I doubt it but nonetheless seems worth checking).

Out of flat by 1/32” seems like a lot even if machined by inferior equipment and/or careless employees. If it is truly out of flat, then I would think that a machine shop would be a better option than trying to sand the cast iron. I would image finding a machine shop that could flatten the top could be a challenge. Sanding could be a slow go. But more than that, ensuring the top is flat when done could become a nightmare; and sand a little too much just adds to the work.

I suspect that a 1/32” height difference in the table could impact your cuts. I made the assumptions that the table is flat from the throat for a distance of 7” to the mitre slot, then table goes out of flat by a step up of 1/32” and thereafter is flat, and that a board to be cut will be longer than 7”. As a result, the end of the board away from the throat (and hence the blade) will be lifted by 1/32”. If the blade is set to 90 degrees to the table surface near the blade where the table is flat, then when the intended square cut is made, it would be 0.25 degrees out of square. This is based on the assumptions above and the assumption that I performed the trigonometric calculation correctly.

On the other hand boards that are short enough to lie in the flat zone of the table would have a 90 degree cut.

In many cases this error in the cut would be inconsequential. But for joinery some extra time could be required either in adjusting the blade tilt or perfecting the cut with a shooting board or mitre trimmer since I am not sure how the 0.25 degree error would look when trying to close a joint.

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bbasiaga

1005 posts in 1830 days


#5 posted 12-24-2016 04:40 PM

The proof is in the pudding as they say. If you are cutting with the results you want, then dont worry. I bet you are fine.

You should also measuRe when everything is assembled. Like suggested above, the weight of the wings etc will change the picture. So check performance when the saw us assembled for use.

Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

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LucasWoods

332 posts in 1168 days


#6 posted 12-24-2016 05:48 PM

Yes I will double check and maybe the wings will level this out a bit more. When I got the saw the wings were not put on correctly I could even feel a lip when moving from the main part of the saw to the wings.

I have to take apart the saw clean it up and remove some very very light surface rust and readjust the motor and install my new link belt.

JBrow

The entire table before the throat and after is the same thickness off 1/32. From the miter slots out to where the wings would be is where it seems the saw is a bit raised on those parts.

When I measured with a machinists try square right around the throat plate it is perfectly square (my try square is 6” long).

-- Colorado Springs, CO

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Loren

9610 posts in 3482 days


#7 posted 12-24-2016 05:52 PM

You can’t fix it without having the top reground.

It’s also normally not a factor in getting good
results on a table saw… flatter is preferable of
course and some makers do flat better than
others but I’ve used both flat and warped
table saws with the same results.

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LucasWoods

332 posts in 1168 days


#8 posted 12-24-2016 06:53 PM

Well that is good to hear lol. Luckily it isn’t warped it is pretty uniform before and after the throat plate

-- Colorado Springs, CO

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OSB

147 posts in 361 days


#9 posted 12-24-2016 08:24 PM

Looking at the g1022, it seems very similar to my no name made in Taiwan contractor saw.

I haven’t taken mine apart but I think the defining feature of a contractor saw is the trunnion is attached to the table rather than the cabinet.

That may result in the table sagging in the middle.

Grinding it flat will thin the casting and possibly make it want to sag more in the future.

I hope mine will flatten up when I clean the surface rust off the table but I’m thinking I might want to make a reinforcement that holds the trunnion up from the saw base instead of just hanging from the table. I’ll probably incorporate a DIY copy of a PALS system so I can preload it upward and square it to the table with the same hardware.

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Carloz

963 posts in 426 days


#10 posted 12-25-2016 07:08 PM

You are in luck. A hump in the center would be much worse than a dip. If you have a dip the stock is always supported at both sides. If you have a hump one side always hangs in the air making it wonder all over the place and inherently unsafe. The flatness error is significantly amplified in this case.

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