Thread: Jig for making small timber wedges

I was unable to find a safe way of making small timber wedges, from small tenon wedges to 200mm long wedges. Admittedly I could use the drop saw or SCMS to make the cross-grained wedges safely, but these are generally not strong enough, and it was definitely not safe making small wedges from timber held at right angles to the saw fence of the drop saw.

The jig I made is suitable for use on a table saw, and could easily be adapted for the bandsaw. You will find the design sketch after the photos below. The jig runs along the mitre slot of the machine, and consists of three parts, a sliding base plate that moves on the table, and an adjustable top plate that moves along the base plate using parallel runners to locate it correctly, and a fixed plate. The sliding top plate is used as a fence for positioning the workpiece at the correct angle against a fixed plate whilst being cut.

The sliding top plate can be adjusted to make wedges from 50 - 200mm in length. This was a personal choice, as I did not expect to make smaller wedges. By inserting a spacer bar, this jig will make 0 - 200mm wedges. For this jig, I have selected a 1 : 7 (8°) slope for the wedges, but this can be any angle , but needs to be decided at the design stage. The fixed plate and the sliding top plate have to be cut at half this angle i.e, 4° for this jig to make the wedges 8°, as the jig works on a cut and flip basis. For making wedges along the grain, I use a rid blade to give the neatest cut.


The jig is made from a single piece of 600 x 600 x 16mm ply, cut to suit. The only other timber required is 19 x 12mm hardwood for runners. In this case I trimmed purchased 19 x 19mm Tasmanian Oak on the saw bench with a slotted hold down jig .

The base plate moves parallel to the sawblade using a 600mm long runner on the under side, and has two grooves on the upper side to take runners from the sliding top plate. The upper plate has a pair of matching grooves and runners inserted. The trick to making sure the runner grooves on the base plate and the sliding top plate align is to use the same reference edge for all grooves when cutting the grooves. It is this reference edge that slides against the fence of the router table for all grooves.

I have added an adjustable toggle clamp to hold the workpiece, angled so the hold down point is as near to the blade as possible. I have also added a readily available ( Bunnings) tri-handle clamp to hold the sliding top plate in position. This clamp screws down on a 3/8" Whitworth bolt mounted through the base plate.

To operate the jig, cut a workpiece to the length of the wedge you require. This can be any thickness, from, say, 4mm to the maximum height of the sawblade (minus the thickness of the base plate). Install this workpiece against the fixed plate on the base plate , correctly aligned to ensure the grain is at right angles to the fixed plate, and then push the sliding top plate up against it, and tighten this plate in position with the tri handle clamp. The toggle clamp is then used to hold down the workpiece while it is being cut.

On the first pass, the angle of the wedge is only half that required, so this can be discarded. Take out the workpiece, leaving the sliding top plate in position, and flip it over so what was the nearest edge against the sliding top plate is now the furthermost edge, and is now positioned against the fixed plate. Slide the workpiece into position, and cut. All subsequent wedges will be at the correct 8° angle as you cut and flip the workpiece.

The only concern is the wedges falling down after being cut, especially with the leading edge of the sawblade rotating up out of the table. This has not proven to be a problem as I have a zero clearance insert on the sawblade, but I found it better if the blade is stopped and the wedges cleared away from the rotating blade every few cuts.

To speed up the process, I have made a small tray with a 45 degree side which fits against the sawblade ( to within a thickness of a business card) and is magnetically clamped to the table. The height of this must be less than the thickness of the base plate. The falling wedges will now fall down the 45° slope, and away from the upward spinning sawblade. This eliminates the need to frequently stop the saw.

wedge_jig_01.jpg
Cutting 100mm board across grain


wedge_jig_02.jpg
Wedges fall down on tray away from blade


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Front view


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Cross cutting wedges


wedge_jig_05.jpg
Jig ready to be pushed forward to cut wedge ( cross grain)



wedge_jig_06.jpg
Stopped mid cut for photo op


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End view of jig showing base plate and top plate


wedge_jig_08.jpg
Cutting a tiny wedge with grain 20 mm long using spacer bar clamped by toggle clamp


wedge_jig_09.jpg
Two 20mm long wedges cut.
Need to take it very slowly towards the end,
or wedge will fly across room


wedge_jig_10.jpg
200mm wedge with grain about to be ripped


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200mm long wedge cut


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100mm wedge cut along grain


wedge_jig_13.jpg
Typical range of wedges cut on tablesaw with jig.
They can be as thick as necessary, up to the height of the sawblade