Table saw cross-cut sled
My Bosch table saw has many great points but a couple of major flaws too.
The mitre slots are non-standard sizes, the supplied mitre gauge is far too loose within them and the built in sliding table is equally inaccurate. While suitable for its intended use of large scale framing by the job site professional, these inaccuracies add up to noticeable flaws in anything requiring closer tolerances and I’ve seen problems first hand on most of the things I’ve built with it to date. For example, small panels for boxes and drawers.
There are ways of correcting the flaws in the table saw but these require an accurate drill press; which my Parkside cheapo from Lidl is not. In fact, there’s enough wobble in the chuck to whip cream using a straight piece of round section bar! .. don’t get me wrong, you get what you pay for and I have several Parkside (Einhell) tools that serve me perfectly well for my needs and level of usage.
The solution is to make a classic cross-cut sled and is something I should have done when I bought the saw over two years ago. I’m using some scrap wood from around the workshop. I have no large pieces of plywood or MDF to use for the base so I’m re-purposing the 3/4 plywood base from a pocket hole jig support that I made last year. This means the sled will be smaller than I would like but it will be able to cut up to about 2”x8” (60x200mm-ish) section stock, which is plenty for most projects. I will have to follow up quickly enough with a panel sled however. The dimensions are 290x475mm.
For the rear (accurate) fence I’m using a couple of strips of 3/4” WBP ply laminated together, with additional pieces dowelled and glued to the top for extra support and blade clearance, when the blade is up to its full height. A length of 2"x4” for the front fence (not required to be accurate) and an additional block of the same off-cut ply for the back of the rear fence so that the blade never emerges there.
I’m making the runners from a tiny strip of oak that was in the offcuts of material I saved from the original kitchen we stripped out of our house when we moved in a few years ago.
YouTube is saturated with videos of cross-cut sled tutorials, so I won’t go into much detail but these are the two I referenced most:
I cut the slat of oak for the runners down roughly on the table saw, halved it lengthways and sanded each half to match with a specific mitre slot on the saw, as they are not consistent sizes. I stopped when each was still a tight fit. I used a few m5 washers in each slot to lift up the two runners, applied wood glue and then placed the base on top, followed by some heavy weights to hold it steady while the glue set. An hour later I came back, flipped it over, pre-drilled and countersunk in some screws. You can see the evidence of its former life as a support for a pocket-hole jig in the small screw holes in the underside. I made sure all of these holes were sanded perfectly flat by the way.
Then sanded the runners a little further until the unit would slide with just a little resistance in the slots before raising the blade about two millimetres above the table and running a scoring cut from one side of the base to the other. This makes it easy to avoid putting screws in line of the blade. I forgot to get a photo of this unfortunately.
I laminated the plywood for the lower and upper sections of the rear fence, added 45 degree mitres to both ends of the upper (central) block and dowelled/glued the block into position on top of the lower section. After the glue dried I sanded the whole piece and used it as a template to mark an identical shape on the 2x4 for the front fence, before cutting out that shape on the band saw. Then I rounded over the exposed edges of both fences and sanded the rear fence further to be comfortable on my hands.
Next I lined up the front fence to the front edge of the base (the inconsistent mitre slots meant it could only go on in one position) and glued and clamped it in position. From underneath I pre-drilled and countersunk 4, 5x70mm woodscrews to hold it in place and left it to dry for a while.
Time for the first through cut. I put the sled centrally over the blade and clamped it to the saw table for safety. Then with the saw running, I slowly raised the blade through the sled until it had made a cut about 6-8 inches long. Then turned off the saw and unplugged it for the next step, which is the bit dreaded by most people making one of these. From beneath I pre-drilled and countersunk a 4x60mm (so I could replace it with a bigger one later) screen in one position on the rear fence before using a combination of 3 different squares and a straight edge to get the fence as close to 90 degrees as I could to the blade and the slot it had cut. I spent about twenty minutes doing just this. Then clamped it in position and similarly inserted a second screw.
I used a small piece of plywood and the 5 cut method to test if the fence was square to the blade and it was weirdly close first go, so close that I had difficulty deciding whether or not I could improve accuracy by trying to adjust it! .. I decided to run with it as-is and I’ll revisit it after the first project I use it for if I find any inaccurate cuts appearing. I pre-drilled and countersunk another 4 screws in from underneath to hold the rear fence firmly in that position.
Then I ran a cut completely through the sled so that I could see where the blade would emerge and then used the sled for its first “proper” cut to trim down one of the mitred offcuts from the central block of the upper fence, which I glued and screwed onto the fence (no glue on the base!) as a safety housing block for the blade. This way I can still adjust or even replace the fence later if I need to. Note the nifty use of dust extraction - this worked amazingly well, so I’ll rig up something safer for the future.
Lastly I applied machine wax to the runners and underside of the base to help it slide more easily (huge difference) and it’s ready for the first project.