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Super accurate crosscut sled

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Project by DaveFFMedic posted 10-24-2012 03:33 PM 8084 views 84 times favorited 22 comments Add to Favorites Watch

This crosscut sled is super accurate. I made it a while back and have been using it for a couple years now. It has two T-track slots, one on either side of the blade to hold down the pieces. There are two handles on the back which help to keep hands away from the blade. The rear block is super thick to help cover the blade as it exits the workpiece.

The second picture shows the extendable stop block which allows me to cut pieces which are longer than my sled is wide. The threaded rod and angle iron nest inside the fence and lock in place with a thumbwheel.

The fence attaches to the sled with two bolts and can be further secured with screws. On the right side of the fence is the fine adjustment mechanism which is of my own design. The third picture is a close up of the mechanism. I tried making a sketchup drawing of how it works, but I couldn’t put it together. The octagon shaped wheel has two threaded inserts, on one side is a 1/4”-20 insert and the other side has a 5/16”-18 insert.

As the wheel is turned, it pulls in the one side and pushes out the other side. Because the movement between the two sides is unequal, for every 18 revolutions of the wheel, the fence moves 1/10”. For those of you doing the math, one revolution is 5 thousands of an inch.

I used the fine adjustment wheel to dial in the fence, then secured the bolts to lock it in.





22 comments so far

View AdrianT's profile

AdrianT

23 posts in 984 days


#1 posted 10-24-2012 04:06 PM

Nice sled. That fine-adjustment wheel is a brilliant idea. I’ll have to use that sometime.

-- I can do all things through Christ who strengthens me... AND I'm an engineer.

View DaveFFMedic's profile

DaveFFMedic

67 posts in 825 days


#2 posted 10-24-2012 04:34 PM

Thanks AdrianT. I’m afraid i didn’t do a very good job of explaining how the mechanism works. I plan to do a blog detailing its construction when I make my box joint jig. I hope to do it within the next two weeks.

View RalphCompton's profile

RalphCompton

63 posts in 1307 days


#3 posted 10-24-2012 06:53 PM

Remarkable! I LIKE! I’ve been wondering about how I am going to built a really accurate sled and you’ve just given me some really good ideas, suggestions, hints, etc. This is on my “next 5” list for sure. Thanks. I CAN DO THIS NOW!

View MShort's profile

MShort

1726 posts in 2077 days


#4 posted 10-24-2012 07:11 PM

Sweeeeet !!!!!

-- Mike, Missouri --- “A positive life can not happen with a negative mind.” ---

View horky's profile

horky

82 posts in 1589 days


#5 posted 10-24-2012 07:35 PM

Dave, really great idea on the adjuster. If I may be sold bold … the 5/16-18 rod gives a movment of 0.055 inches per single revolution. The 1/4-20 rod gives a movement of 0.050 inches per single revolution. Since one is pushing (unscrewing) and one is pulling (screwing), the difference 0.055 minus 0.050 or 0.005 inches, is the movement of the fence for one revolution of the adjuster wheel. ... very accurate adjustments for truly fine tuning the fence. Thanks for sharing this as many of us will put it to good use.

View bobasaurus's profile

bobasaurus

1261 posts in 1842 days


#6 posted 10-24-2012 09:26 PM

This is one of the best crosscut sleds I’ve seen. Fantastic job… I might be stealing this soon.

-- Allen, Colorado

View DaveFFMedic's profile

DaveFFMedic

67 posts in 825 days


#7 posted 10-24-2012 10:54 PM

Thanks everyone. I thought long and hard about how to make my own micro-adjuster. The two different pitched threaded rods provided the perfect solution. The hardest part was figuring out how to join the two different parts. I first tried to turn and thread a rod, but had trouble getting the two halves concentric. I decided that the threaded inserts would be the next best thing. As an added bonus, it provided a thumb wheel for tool-free adjustments.

View hjt's profile

hjt

776 posts in 1797 days


#8 posted 10-25-2012 01:06 AM

Would like to see photos of this in use, on your table saw. Hope you’ll add some photos.

-- Harold

View a1Jim's profile

a1Jim

112106 posts in 2235 days


#9 posted 10-25-2012 01:10 AM

Unique design and well done.

-- http://artisticwoodstudio.com Custom furniture

View Ralph's profile

Ralph

160 posts in 791 days


#10 posted 10-25-2012 01:48 AM

Nice sled. Very original adjustment. I like the extension to the width of the sled.
Sorry for being dense, but other than the original sled setting, what do you use the adjustment for?

-- The greatest risk is not taking one...

View DaveFFMedic's profile

DaveFFMedic

67 posts in 825 days


#11 posted 10-25-2012 02:03 AM

Ralph: after the initial setup, the adjustment isn’t used anymore unless the jig becomes misaligned. If I had made the jig so the adjustment wheel could be easily removed, it could be reused on other jigs.

View chopnhack's profile

chopnhack

368 posts in 1053 days


#12 posted 10-25-2012 02:08 AM

First, awesome design! Second, I have the same question as Ralph…. did you leave the adjuster on for future recalibration? Is your top hardboard on top of ply or mdf? I love the handles, very smart and easy way to keep the hands out of harms way.

-- Sneaking up on the line....

View JJohnston's profile

JJohnston

1578 posts in 1950 days


#13 posted 10-25-2012 02:14 AM

I just had a flash of inspiration/understanding, and I know how the adjust mechanism works! Sort of like a turnbuckle, but instead of both in or both out, it’s one in/one out, at different rates, am I right?

Seems super simple to build, too – one through hole and 2 inserts?

-- "Sorry I'm late. Somebody tampered with my brakes." "You should have been early, then."

View Ralph's profile

Ralph

160 posts in 791 days


#14 posted 10-25-2012 02:35 AM

Too bad you can’t use it elsewhere. I wonder if a universal adjustment can be made with that mechanism.

-- The greatest risk is not taking one...

View DanoP's profile

DanoP

135 posts in 998 days


#15 posted 10-25-2012 02:55 AM

Love the idea. I’m sure we will be seeing these pop up for different applications. I have only one suggestion that would take this over the top… Pentagon adjustment knob. One flat = one thou!

Well done!

-- We've got enough youth. Let's search for a fountain of smart.

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