crosscut sled question

[Salty]

I have decided that I now need to make one of these for my next project.
I already have the dual miter installed.
Is there a 'rule-of-thumb' for the width and depth of the sled?
The panels I need to cut will be 3/4" plywood, 23" wide and 30" long.

I am thinking that the depth should be the width of the panel plus the distance from the front of the tablesaw to the center of the blade. Is that about right?

Thanks.

Salty

[pecker]

Put your SMT back on, and clamp a temporary fence to it. It will save you a lot of time and effort. Putting a smaller blade on will give a little more crosscut capacity, also.

[Salty]

Put your SMT back on, and clamp a temporary fence to it. It will save you a lot of time and effort. Putting a smaller blade on will give a little more crosscut capacity, also.]

Good solution but I don't have any clamps with that low of a clearance to avoid hitting the front rail.

But, I did remember that I had made an aux miter slot out of some angles and MDF.
So, I set that one 18" to the left of the dual slot and extended the rails to the right just enough to put on the SMT to support the cutoff piece on the right.
I glued and clamped 2 pieces onto the plywood sled to slide into the miter slots. I'll let that dry till tomorrow and then put some screws into them. That should let me do what I need.
I may also attach my outfeed table to the left end of the rails to give me something to rest the long side of the plywood. If this works out well I will leave it set up and cut the 1/2" pieces as well.

Salty

[dkerfoot]

I had poor luck fitting two guides into the dual miter slots. No matter how much I fiddled with them, the sled was always either sticky or sloppy (mostly sticky). Having the guides so close together causes the sled to want to rotate and the guides bind. From a Physics standpoint, it is much easier if you have the guides further apart. I ended up using the slot on the dual miter table that is furthest from the blade and then used the opposite saw table edge to run the 2nd guide against. This works much better in my experience.

I don't know of a general guideline, but in practice, the less you have hanging over the front or back edge of the saw(at any point of the cut), the more stable, accurate and safe it will be.

23" wide panels sound to me like they are simply too wide to safely use a cross-cut sled on a shallow TS like the BT3/21829. The real advantage of sleds on these saws is when cutting very small parts. I use my sleds for boxes, where I may be cutting 2" x 2" parts.

I'd follow Pecker's advice. The SMT is going to provide much more stability. A pair of small c-clamps will cost less than the wood to build a sled and when you are done with this project - Hey, more clamps!

[pecker]

The clamps are the 1" c-clamps that Harborfreight sells for about a dollar each.

[pelligrini]

I was using a pair of those Rockler universal fence clamps to set up my SMT in a similar fashion last weekend. Those took care of any clearance issues.

I'll probably just drill some holes through on the ends of the SMT for some T-bolts eventually.

[Salty]

Well, what I made worked but it was less than ideal. Much better than freehanding, using a router or circular saw.
I discovered that it is important to use a sled that is wider that the board being cut. Mine is not and I struggled some having to hold the board up and slide it as well.
Dkerfoot is correct in that using 2 slides is problematic. I'll build another one I'm sure but it will be a better one.
The plywood I used has some warping which I did not originally notice and that does not help at all. Also, it is 3/4" thick. I think I'll try one with a piece of 1/2" MDF so the blade doesn't have to be so high.
And finnally, I think I'll pay the extra dollars to have the plywood cut into smaller pieces that fit my dimension needs. That way I don't have to try to sled 2'x8' pieces. I cut then slightly bigger anyway and then trim them so I may as well have that done on the panel saw at the yard.