Thread: Cross cut sled accuracy.

Originally Posted by DaveVman

This is all a bit depressing because I'm not even getting consistent results from my sled. ...

No its not; you are more than half way to a solution, and you will appreciate it when you get there.

As per Chris's video, I would check the blade alignment first, then the fence alignment.

I have a slight variation in methodology. I lay a straight edge - an aluminium spirit level - against the carbide saw teeth, and check the alignment against that.

Always keep in mind that we are machining wood!

Wood has a life of its own, it moves when drying, being machined, even just sitting there waiting to be used, as we assemble it, then in service as a finished piece - daily and seasonally due to the humidity in the environment it is stored in. Wood has some very unique natural properties, it is not homogeneous, it stores internal stresses, it can act like a sponge and take up moisture quite rapidly.

Yes, we should stack the odds in our favour by setting up our machinery, jigs etc as best we can, but we must face the inevitable that wood will move. Many of the issues we face in the build phase can be minimized by our work practices, using complimentary cuts which will tend to eliminate the errors in cutting, then tweaking the cuts by using shooting boards etc to 'favour' certain elements to produce clean consistent joints. Note I said consistent - all should look the same, one very tight or very loose joint against say all loose or all tight - or uniform joints, will stand out.

Aim for consistency not perfection. Always be mindful of how, why and when it will move in the build phase then in service.

IF I were to reject every component that 'does not meet specs' for the inlay bandings that I love to make I would waste a significant amount of time and effort in cutting, then in quality control. The secret is setting up your gear as best you can, then work on methods that produce consistent results.

If you've got a Sawstop PCS or ICS, the manual covers everything and it'll take an hour or so at most. The hardest step I had in setting up my PCS was one bolt that needed a rattle gun to loosen - someone got a little too torquey with it at the factory.

Edit: I only mention the PCS and ICS as I'm familiar with them, I'm sure the jobsite and contractors saw manuals will also cover aligning blade to mitre slot.

I have an inexpensive saw and I found it had changed since I had made my sled. I later found out the entire saw mechanism was cantilevered off the front of the saw case with nothing at the back at all. Did I mention I also found it to be a little too flexible. So I got a bar and bent it back square as best I could. I also found a zero clearance insert helps keep the blade in plane. Not ideal but I can work around it for now.

1mm is far too much - doing this on a panel saw it would Need correction over a metre - not 200 odd mm. IF your blade is not in line with your guides - that is and will always be an issue! If your guides on your sled are loose - issue - if made of wood go for something like spotted gum or cypress pine(the Aussie stuff that they use for posts and palings ) Hard dense and slippery. If you can get some offcuts of compressed laminate - think laminate 12 or whatever thick - hard as and smooth sliding a well! Expensive though!

Originally Posted by wood spirit

... If your guides on your sled are loose - issue - if made of wood go for something like spotted gum or cypress pine(the Aussie stuff that they use for posts and palings ) Hard dense and slippery. ...

Agreed.

But I think that UHMWPE plastic is even better.