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How accurate is your table saw cross cut sled

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Forum topic by MikeGraw posted 08-11-2019 09:30 PM 713 views 0 times favorited 12 replies Add to Favorites Watch
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MikeGraw

24 posts in 3369 days


08-11-2019 09:30 PM

I got my cross sled to within 1/64th at 9 1/2 inches. I am hesitant to mess with it anymore less i make it worse. The widest board i can cut on my sled is about 24 inches. That is about 2 1/2 64ths over the course of the 24 inches.

Would call that close enough or try to get it head on?

-- Mike's having fun in Central Wisconsin


12 replies so far

View squazo's profile

squazo

131 posts in 2092 days


#1 posted 08-11-2019 09:50 PM

if thats good enough for the work you do then its good enough.

I however went full on obsessive mode and got it “perfect”. It doesn’t take too much more time and its convenient to know you r cross cuts are “perfect”

View woodthaticould's profile

woodthaticould

62 posts in 2774 days


#2 posted 08-11-2019 09:53 PM

I’m not saying that I could do any better with your set up, but it doesn’t sound close enough for accurate work. Just wondering, are you aware of “the William NG method?” If not you can see it here:

https://www.youtube.com/watch?v=UbG-n--LFgQ&t=137s

View Rich's profile

Rich

4676 posts in 1036 days


#3 posted 08-11-2019 10:08 PM

I’m with woodthaticould, that’s almost 0.002 inches per inch. You really want to shoot for less than 0.001. Especially when you might be making a 24” cut. That’s over 0.04 inches of error and definitely enough to throw you off when you assemble.

Even with narrower cuts, if it’s on the end of a table apron and the table legs are 30”, they’ll be off.

-- Knowledge is not skill. Knowledge plus ten thousand times is skill. -- Shinichi Suzuki

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therealSteveN

3351 posts in 1021 days


#4 posted 08-11-2019 10:48 PM

Wood moves this is a given, it also clouds the issue around tool set up,how fine to go. I always shoot for .001 overall. and if I get less, Woohoo. If your tools aren’t the issue with why anything doesn’t fit, work out, or whatever. If you know the tool is good, then you need to look at what you are doing.

If final cuts are good off a miter saw, ok, don’t get as excited about the numbers unless they are bigger, and NOT leaning toe in toward the blade, that can become a safety thing quick.

Specifically to so with sleds on a TS, make sure your runners are NOT sloppy. I see this on a number of visits to help local guys tune in a sled. They do all the steps in the video, but have so much wiggle in the miter slots it doesn’t matter. Those Incra adjustables are well worth the coin.

-- Think safe, be safe

View Nubsnstubs's profile

Nubsnstubs

1588 posts in 2177 days


#5 posted 08-11-2019 11:14 PM

If all you’re going to be cutting is 24 wide stock, there might be a problem. More than likely, you will be cutting a lot more material less than 4” wide.

That 2 1/2 64th” equals just over 1/32”. I challenge anyone to be able to visually see it. Hell, I can barely see it on my machinist 6” ruler…. Face reality, you have reached your purrfection point. Live with it. After your product is assembled and used awhile, you’ll forget you were off a 32nd of an inch.
Mike, I’m not criticizing you but the other purrfectionists…... .........................Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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mdhills

22 posts in 3079 days


#6 posted 08-11-2019 11:25 PM

I futzed with mine a bit beyond that, and am content to have done it… once.

Getting the runners to fit well is good advice.
And to realize accuracy, you will need to be careful to remove any debris that rests up against your fence. (I didn’t cut out a relief)

Matt

View MikeGraw's profile

MikeGraw

24 posts in 3369 days


#7 posted 08-12-2019 01:41 AM

Wouldthaticould. That is how i test it. That’s how i finally found i was off on the sled. Originally i was off by over 7/33nds. I was given the sled and just finally got around to verifying it for square.

-- Mike's having fun in Central Wisconsin

View Dark_Lightning's profile

Dark_Lightning

3486 posts in 3556 days


#8 posted 08-13-2019 01:19 AM

I dialed mine in to .004” over an 8” cut. The reason for this is I made a few tool chests and I wanted a piston fit for the side-hung drawers. By the time I got them assembled, I had them ~1/32 out of square. Small errors add up.

-- Steven.......Random Orbital Nailer

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MikeGraw

24 posts in 3369 days


#9 posted 08-15-2019 04:53 AM

Well, i played with it a little more and got it right on. Thanks for all the help.

-- Mike's having fun in Central Wisconsin

View RRBOU's profile

RRBOU

178 posts in 2739 days


#10 posted 08-15-2019 10:58 AM

I have constructed several sleds for my self and friends. I always shoot for less than .004 over 20”. I can see this small amount in a finished project.

Is this much accuracy really needed? for me yes for others no. One phrase I hate and will not tolerate in my shop is CLOSE ENOUGH.

Absolutely can not see or can not feel is all that I accept for myself. I will accept someone making the statement NOT PERFECT BUT USABLE.

A good example is a shop that I am setting up for my father. He is utilizing a space that is 16’ wide by 20’ long. Prior to my arrival he had a 4” concrete floor installed. this space is 1/4 of an open two bay area. it is utilizing the South and East corner of this area. it uses two existing walls.

When I arrived the floor had a 2” rise to the back corner of the 2 existing walls. he had also framed in the front wall.

In the front wall we had discussed installing a 5’ wide space using a 3’ and 2’ door in this space. He said that it took him 4 days to do the front wall. He installed two gates (to include the hardware IE hinges and clasps) for doors and the rest was even worse. His comment was good enough. My comment was it is not even in the same zip code.

He stated that if I thought I could do better there was still a 20’ wall to put in. It took 2 days but I did it. When I told him it was completed he said well lets see how mister perfect does it.

I handed him my feeler gauge set and stated that for the last 25 years I have held steel fabrication that I inspected to a tolerance of 10 thousands for a tight fit and 1/32” for a snug fit, by code. I also told him that I held myself to a standard of 5 thousands for this build.

He was amassed that he could not find a spot that he could get a 6 thousands gauge into. his next question was how did I get the studs to 24” centers so accurately and I handed hie 4 story sticks that I made and 2 quick grips that I used,.and showed him the sleds I made for his table saw. I told him give it a few days for the wood to move and he is likely to find areas he can get a gauge in.

He said that the reason his wall took 4 days to construct was because he had to make and install the double doors. I corrected him and stated that the area was covered by gates not doors. to include the hard ware of hinges and latches.

I said that as bad as his was it was usable. And he should call the concrete company and refuse to accept the floor slab. Also we needed to work on his accuracy.

-- If guns cause crime all of mine are defective Randy

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MrRon

5616 posts in 3690 days


#11 posted 08-16-2019 12:27 AM

It’s fairly easy to make things in wood to thousands of an inch. The problem is wood is subject to shrinkage and expansion. It will change with humidity and temperature. The best you can do is try to get it as close to perfect as possible. The wood will wander without any coaxing all by itself. Even metal will change it’s dimensions though not as much as wood. That’s why we work to tolerance levels and if we are within tolerance, that’s the best we can do. Just set your tolerance level and live with it. Being within a tolerance, is considered “good enough”. I have made sleds that work perfect one day and the next, it either sticks or is too sloppy.

View Sark's profile

Sark

152 posts in 807 days


#12 posted 08-16-2019 02:44 PM

The William NG method posted by woodthatIcould above, is amazing! Thanks for posting. And to the OP, I suggest that you use this method to tune your current cut-off box or build a new one. It will get you to an accuracy far beyond what you are getting now. I absolutely would not accept 1/64 of an inch as good enough. The NG method really isn’t any harder than what you’ve done, it just guarantees much more accurate results.

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