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tablesaw tape is inaccurate. Bad setup or just need new tape?

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Forum topic by guitchess posted 07-18-2012 11:24 AM 2427 views 0 times favorited 15 replies Add to Favorites Watch
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guitchess

82 posts in 2361 days


07-18-2012 11:24 AM

Topic tags/keywords: tablesaw setup tablesaw tape question

Hello.


While ripping some plywood for a countertop the other day I noticed it was a 1/16” wider than it was meant to be. So, I thought I bumped the fence to hard with the sheet. It’s a little awkward to maneuver a full sheet of 3/4 ply and I occasionally let it against the fence to hard. However, when I checked the tape, it showed that it was still dead on. I then started checking every thing. Which revealed that the tape is more accurate as it is closer to the blade. At less than 12” there is no visible error. But as you move to 16”, the error grows to 1/32” and then grows to almost 3/32” at 30”. I thought this may because the tape had been stretched when installed, but it reads within 1/32 when compared to my tape measure. So, my question is, is there a setup issue that could cause this varying error, or do I just need to get a new tablesaw tape?


I’ve checked all the normal setups with a dial and everything reads less than .002” error.


15 replies so far

View jmos's profile

jmos

681 posts in 1022 days


#1 posted 07-18-2012 11:38 AM

No expert here, but if you don’t think the tape is stretched, it might just not be that accurate. My TS does the same thing, the further out you get the further off it is, much like you described. I think it’s just a cheap tape where the graduation are not dead on. A good quality replacement might be in order.

I’ve taken to using a ruler or tape to check all my setup, and only use the tape as a rough guide.

-- John

View Bill White's profile

Bill White

3451 posts in 2613 days


#2 posted 07-18-2012 04:14 PM

The fence tapes on my equipment are only used as a rough guide. I ALWAYS re-measure with a good scale. Always done it that way-guess I always will ‘cause that’s the way I was tought. Did ya get the word “always” being used a lot?
Bill

-- bill@magraphics.us

View MonteCristo's profile

MonteCristo

2097 posts in 841 days


#3 posted 07-18-2012 04:29 PM

I have a lot of rules (steel), tapes . . . It’s interesting to line them up and compare. Cheap rules sometimes are off noticeably.

I’ve had good luck with the rules on my table saws but they are high quality saws and maybe they actually used good rules.

Something is fishy if the error grows, then reduces . . . If the saw rule agrees with a good quality rule (I would not call a standard carpenter’s tape a particularly good rule), then it’s quite mysterious as to what’s up. Usually when the saw rule is off it’s because a blade with a different kerf width is being used or, as you say, the fence got bumped.

Anytime you hit the fence you should check for fence alignment, as if it’s no longer parallel to the blade the quality of cut will also suffer and, if it’s now pinching, you could also be inviting kickback.

-- Dwight - "Free legal advice available - contact Dewey, Cheetam & Howe""

View Finisher's profile

Finisher

31 posts in 791 days


#4 posted 07-20-2012 01:14 AM

What brand of table saw do you have. I purchased a Grizzly G0691 two years ago and shortly after setting it up I had to rip some plywood and had a similiar problem. I didn’t think it was the tape because it came from the factory already mounted. I went entirely through the set up process again thinking I missed a step but still got the same results. Well, I decided to double check the tape itself and found that it was 3/16 out at 48 inches but cutting narrower pieces the error was much less. Long story short it was a bad tape. The company sent me a new tape and it was the same as the first. By the way, to be a whole 32nd out is to much. Your tolerances should be not more than 1/64th. Anyway, I am a firm believer of using one brand of tape measure in my shop not various makes. They all measure different from each other and that 1/16 difference can make a real problem when it comes to assembly. Fourtunately the tape brand I use also makes a medal self adhesive flat tape and I replace the one on the machine with it. Now I never have a difference from what I cut on the table saw or on my cross cut saw because everything is calebrated the same. The only other thing that comes to mind might be the lock on your fence sometimes they allow the fence to budge a little when you slide your piece against it to begin your cut. And finally, if your fence and the blade are not properly aligned the work can drive away from the fence during the cut giving you the results you talking about.

-- James, Michigan http://www.northcapecabinetsandmillwork.com

View Sawkerf's profile

Sawkerf

1730 posts in 1721 days


#5 posted 07-20-2012 01:26 AM

I’ve had issues in the past with the vinyl “peel and stick” tapes. They can stretch when you pull on them.

Now, I have a steel “peel and stick” that was kinda spendy but is accurate. Even so, I almost always whip out my tape when setting the fence.

-- Adversity doesn't build character...................it reveals it.

View PurpLev's profile

PurpLev

8476 posts in 2301 days


#6 posted 07-20-2012 01:41 AM

first and foremost I would check the TS rule with another rule- that rule does not have to be all that precise – you measure 5” on the TS against 0-5” on your other tape, if that compares, you move your other tape and measure 5-10” on your TS to 0-5” on your other tape (which is known to be identical to your TS 0-5”) – rinse and repeat, if your TS tape is stretched/compressed anywhere along the way, it’ll be pretty noticeable.

If this measures up, than another possibility is that your fence is not parallel to the blade. and for some reason the more you move it away from the blade, the less parallel it becomes.

All that aside – I never really use the TS tape for anything other than rough locating of the fence. I always use a gauge, or another steel square/ruler to get the actual distance to blade from fence.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View lieutenantdan's profile

lieutenantdan

176 posts in 959 days


#7 posted 07-20-2012 02:09 AM

Measure twice, cut once. I never trust or use the tape on my fence.

-- "Of all the things I have lost in life, I miss my mind the most."

View hjt's profile

hjt

776 posts in 1791 days


#8 posted 07-20-2012 02:27 AM

I agree with many of the points already comments. I ‘ve learned to use the tape on theTS as a rough guide. I then measure from the fence to the blade with a second tape measure. I have also noticed that my fence has a tendancy to move at the far end when I begin to clamp it down. So I now measure both sides to the blade – the entrance point and the exit point to the fence. I tap the fence in line and press the clamp down to the lock position. Some day I’ll tear this and my radial arm apart and rebuild.

Hey MonteCristo what do you consider to be a good quality rule?

-- Harold

View bondogaposis's profile

bondogaposis

2528 posts in 1004 days


#9 posted 07-20-2012 03:33 AM

I almost never use the tape on the saw except as a rough guide. I measure the actual distance from the fence to the blade w/ a rule or tape that I trust.

-- Bondo Gaposis

View gooddealonly's profile

gooddealonly

2 posts in 791 days


#10 posted 07-20-2012 04:09 AM

I have a better solution. Use a LCD digital Readout for Table saw.

I bought the LCD Digital Readout for table saw on eBay for about $50.00 including shipping. NEW!

Here is how it works: There is a fixed electronic rail scale attach to the original fence rail and a moving digital sensor with digital readout attach to the fence. When the fence moves on the electronic scale, the display show the measurement. Of course there is the initial calibration of where “zero” is. The zero calibration is where the saw blade just barely touch the fence and push a “Zero” button.

It took me about 30 minutes to figure out how to install it to my Craftsman table saw. Another 30 minute for the actual installation.

The digital readout display and sensor is attached to the rip fence with a wing nut and can be detached very easily. The aluminum thingy with black knob on the right is my home made micro adjustment.

The long black handle knobs turns a screw though a threaded block on the left and cause the fence to move left or right with micro movement. The small threaded aluminum block is attached to the fence base with a fixed screw and a wing nut. The round knob on the top locks the micro adjustment to the rail. The entire micro adjustment assembly can be removed from the rip fence base.

I simply move the fence to approximately 5”, lock down the micro adjustment, turn the long adjustment handle until the digital read out is 5.000. Lock the fence and cut.

Measure with my digital caliper. It is close enough!

The LCD digital read out saves lot of time. The difference between the table saw digital readout and my digital read out is quit consistent.

The nice thing about the table saw digital readout is now I can now calculate and dial in where the cut should be.

For example: the kerf of my table saw blade is 0.125. The MDF board is 0.5 inch thick. I need to cut a slot with the blade in the middle a 1.5 inch strip of the 0.5 inch MDF board on the 0.5 inch side. Therefore:

0.5” – 0.125” = 0.375”
Divide that in two = 0.375/2 = 0.1875

I would set the fence to 0.1875 with the micro adjustment. The first test cut may not be exactly in the middle due to error somewhere but I would know where the tweak the micro adjustment.

For about $50.00 and about an hours time, the table saw digital readout beats the tape an time. My table saw readout measure to 24”. Units measure 6” to 36” are available. I install my unit on the right side of the blade. The unit is very usable even without a micro adjustment.

The installation of the table saw digital read out would be different for different brand and model. I had to drill holes in the base of the sliding head of my rip fence to made it detachable.

You can find the unit by search on eBay with keyword: Table Digital Readout
Look for FREE SHIPPING.

-- I got it done because I have no idea it was suppose to be impossible.

View Finisher's profile

Finisher

31 posts in 791 days


#11 posted 07-20-2012 08:55 PM

One more thought here, If you have an imported machine (as most of them are these days) check to make sure the side of the fence you run your material against is straight. Mine wasn’t! I slight bow will cause your material to track away from the blade. I switched out the phenolic plates for 1/2” baltic birch plywood then covered it with laminate.

-- James, Michigan http://www.northcapecabinetsandmillwork.com

View bandit571's profile

bandit571

6956 posts in 1336 days


#12 posted 07-20-2012 09:45 PM

Emerson built Sears Craftsman: Tape wasn’t even close. When I upgraded the saw, the tape went in the trash can. I never trusted it anyway. Most set-ups I do will involve a Combo square, reference off the miter slot, with the blade between the slot and the fence. I check the front and the back of the slot, just to make sure things are square. I use the same tape measure, AND the same square, throughout the project. One tape measure, one square. My system, and I’ve used it for almost as long as I’ve had the saw. Bought that new, back in the early 80s

-- A Planer? I'M the planer, this is what I use

View Knothead62's profile

Knothead62

2364 posts in 1614 days


#13 posted 07-21-2012 10:35 AM

I always use a good tape measure; don’t trust the ruler on the saw.

View hjt's profile

hjt

776 posts in 1791 days


#14 posted 07-31-2012 04:30 AM

Gooddealonly – GREAT!!! information you shared.

-- Harold

View guitchess's profile

guitchess

82 posts in 2361 days


#15 posted 08-04-2012 05:14 PM

First of all thank you to all who posted their input. I love the different views, ideas, and ww backgrounds that this forum provides.


While I am all about using the most accurate methods possible, I still like to use the fence tape. Maybe it’s because I’m just hard headed, but I find it hard to believe that a $1,000 tablesaw that has been adjusted to within a few thousandths in every direction can’t be made to have a trustworthy fence tape. It could also be that for the first 15 years of my career I’ve had to measure the front of the blade, then to the back, then to the miter slot, etc. I would rather use up what little patience I have perfecting the fit and finish of a project than fiddling with an untrustworthy piece of machinery. Just a hang up of mine I guess.


I have now fixed the issue. After closer examination I determined that it was a stretched tape. Recently, while perusing wally world I found a Komelon adhesive backed steel tape. It was only a third of the price of a steel version I found online so I thought I would give it as shot. I am very pleased. On the two projects that I have worked on since installation, every cut has been within 1/64”. This accuracy is maintained all the way out to 24”. That is as long as my metal ruler is so I don’t have a super accurate way to test beyond that. Plus, I’m sure some of you would agree that if it needed to be closer than that, the tablesaw shouldn’t be the final cut anyway. Especially, since I’m currently using a cheap Harbor Freight blade. Before you holler, I use it because I have recently been cutting a bunch of recycled lumber with paint and other debris. And It is a surprisingly good blade for $25.


Thanks

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