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Crosscut Sled Problem

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Forum topic by OleDL posted 06-10-2017 12:31 PM 817 views 0 times favorited 9 replies Add to Favorites Watch
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OleDL

11 posts in 1273 days


06-10-2017 12:31 PM

Hey, Everyone. This is my first forum post so I apologize if it’s in the wrong place or been covered before, but I couldn’t find my specific problem.

Anyways, I built a sled out of 1/2” MDF for the base and red oak scrap for the front and back fences. Using leftover 1/2” MDF, I did the 5-cut test method and got the front fence to .005” accuracy and then finally down to .003”. The blade and fence are both at 90 degrees to the base. So at this point, all seems good. The saw rips my milled stock (8/4) fine). However, when I crosscut the same pieces (using the sled) to square the ends, they never come out right, even when flush to the sled base and fence fence. This is especially a problem when cutting the pieces for end-grain cutting boards. Again, the long side of the board remains flush to to the sled base and fence, but the cut pieces (usually 1.5”) aren’t square. It seems the ends of the cut pieces are good and then the cut “protrudes” out almost like a wobble. I thought maybe the blade was loose, but no. I thought I might not be holding the piece tight enough, but even clamping didn’t help. I’m about to lose it!!!

My last thought is that maybe it’s the blade??? I’m using a Diablo Ultra Finish 80 tooth blade. Should I try a lower tooth blade for the cross cuts? This one is doing great on the rips and I wanted a fine crosscut on the cutting board pieces to prevent as much gap as possible, especially when flipping pieces.

I hope I describe this right and sorry for making it so long, but it’s driving me nuts! lol Thank you for any help/advice you may be able to give


9 replies so far

View BlasterStumps's profile

BlasterStumps

397 posts in 273 days


#1 posted 06-10-2017 12:38 PM

What is the cut like without the sled? IOWs using a mitre gauge.

View jonah's profile

jonah

1443 posts in 3132 days


#2 posted 06-10-2017 12:49 PM

Is the stock milled square and straight, with parallel faces and square edges? If the edges and faces aren’t square when you rip them, you’ll end up with two out of square edges. Then you’ll crosscut into pieces that also aren’t square.

View Rich's profile

Rich

1972 posts in 423 days


#3 posted 06-10-2017 02:05 PM

If I understand what you’re saying correctly, the cut starts out square and then curves. What does the kerf in the sled look like? Is it nice and straight, and still maintaining zero clearance to the blade?

-- No matter how much you push the envelope, it'll still be stationery.

View rwe2156's profile (online now)

rwe2156

2710 posts in 1314 days


#4 posted 06-10-2017 04:05 PM

First thing I would do is check what Jonah ^ said. You may have a slight taper to the board, which can have to do with how you mill the wood.

Also, try clamping the piece to the sled fence when cutting.

-- Everything is a prototype thats why its one of a kind!!

View Logan Windram's profile

Logan Windram

341 posts in 2295 days


#5 posted 06-10-2017 05:29 PM

My sled is dead on accurate, and I built my adjustable.. however, I still find i use a shooting board to do final squaring… the blade deflecting a little, to much pressure on the push, to little pressure, slight inperfection in the slides, humidity changes, and on and on… I find I get almost perfect dead on when I don’t do a dust cut to get something square…

Building a study well thought out shooting board, you’ll projects will be that much better…

View OleDL's profile

OleDL

11 posts in 1273 days


#6 posted 06-11-2017 12:27 AM

Thanks, for the replies. To respond, yes, the milling is great. I use a shooting board to get the first straight line cheek and the same board for my lunchbox planer. This method has been giving me great results. The kerf line in the sled is great, too. However, I was thinking about Rich’s reply and yes, the cut starts and ends square, with a curve in the middle. After spending a couple hours looking at everything again, I think I found my problem.

I checked the entire base with a straight edge and found a low spot just to the left of the kerf about 3” in front of the front fence! It’s big enough yet still small enough that when I did my test cuts with MDF or “little” pine, they weren’t affected. But when I used the bigger stock or cutting boards (things with weight), they clearly were affected. I actually think I could shim this with folding a piece of printer paper a couple time, but I’ll just replace the base since I’ll be able to reuse the fences and mitre rails since this one turned out so good. Only question now is should I stick with the MDF or maybe a birch plywood?

Thanks again, everyone.

View Rich's profile

Rich

1972 posts in 423 days


#7 posted 06-11-2017 12:46 AM

Glad you found the problem. As for the base of the sled, I always use MDF. I see plenty of them in people’s photos that are birch, so it’s just a personal preference of mine. I’ve had birch bow on me, MDF never has, just so long as you don’t get it wet.

Bottom line is, I doubt if it matters a great deal.

-- No matter how much you push the envelope, it'll still be stationery.

View richardchaos's profile

richardchaos

521 posts in 213 days


#8 posted 06-11-2017 12:50 AM

Are you using a RIGID saw?

-- “In a time of universal deceit, telling the truth is a revolutionary act.” ― George Orwell

View OleDL's profile

OleDL

11 posts in 1273 days


#9 posted 06-11-2017 12:57 AM

Pretty much what I was thinking about the base. I was so happy with how this one turned out, just took for granted that it would be flat and it basically was, still can’t believe I found this low spot because it was so minute. :)

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