Two Jigs For Perfect Resawing
Words and photos: Darren Oates
The jigs shown here were born out of necessity during a commission I took on for an extendable dining table. The client had already purchased one of my arched hall tables and wanted a dining table in the same style. The problem was he lived in a tiny apartment in inner Sydney and couldn’t have a full time dining table due to lack of space.
The piece was to be used as an oversized side table most of its life and only occasionally as a dining table, where the unbraced leaves would be folded out and rested on a retractable support. As the leaves fold back there could be no bracing so I chose not to use solid timber, but instead used a sheet of 18mm hardwood plywood which had 3mm sawn veneers bonded to it with two part epoxy.
This table is shown above and measured 2000 x 1100mm wide which meant I had to saw 8 x 2000mm long veneers at 275mm wide. Sawing two metre long veneers by trying to keep the timber hard up against the fence while pushing through the blade did not seem to be an easy task.
I made two bandsaw jigs to make this easier. One is an extension of the original rip fence supplied with the saw, and the other is a springloaded jig with ball bearing rollers that keeps the timber hard up against the fence without making it hard to push the timber through.
With this setup the only thing I had to worry about was keeping a consistent feed rate and this ended up netting great results for the sawn veneers. I was using three consecutively cut, one inch boards of Mackay cedar and needed to get three veneers from each board. To achieve the 3mm veneers the timber was initially sawn to a thickness of 4.5mm. This gave enough thickness to allow cleaning up on my drum sander to the required thickness, ensuring no saw marks were left. It also gave me one spare board, just in case.
The fence extension can be constructed with whatever you have lying around the workshop—I used 18mm MDF for the base, face and 90° bracing. The fence is the same length as the table for ease of clamping while sawing. The bracing can be made anyway you like, but the fence must be 90° to the base.
Above: Use rollers at the start and finish of the cut so you don’t you have to support the weight of the timber and can fully concentrate on the feed rate. When the timber reaches a point where I can’t push it, I go to the other side and pull the remainder through the blade.
My fence is 300mm high. I very rarely resaw wider boards than this, but it is high enough to support any boards that are higher. The extended fence also makes it a lot easier to adjust your saw table so that it is 90° to your sawblade, as you can measure the distance from the extended fence face to the back of the sawblade and adjust the saw table until an equal distance is measured along the length of the blade. I leave the supplied manufacturers fence on the table as I have set this up to account for blade drift. I then butt the extended fence up against the original fence so that I don’t have to realign for drift, and then clamp it to the table.
To make it easier to mount the jigs to the table I epoxied 32mm MDF to the bottom of the saw table where the various clamps are fitted.
The springloaded jig can also be made out of materials to hand—I used some 32mm MDF. The ball bearing rollers were sourced from Carbatec. This jig has been made the same length as the table so that clamps can be mounted on every side of the jig. The base has a hardwood runner that sits in the mitre track on the saw table.
In the diagram above you can see the top of the base has two runners which are fitted perpendicular to the tablesaw track. The top half of the jig then has two slots machined into the bottom face so they will slide along the runners. In this way the springloaded face adjusts to the width of the timber being sawn. Two coach bolts are fixed to the base and pass though the top of the jig through a slot which can be loosened and tightened when the correct thickness is achieved. The two hooks are just for hanging the jig on the wall for when it is not being used.
The extra dust extraction hose that I mounted next to the lower blade guides, which helps reduce the dust produced while resawing.
On top of this is a brace which must be mounted 90° to the base for which the springloaded face is fitted to. The springs were sourced from a cylinder head reconditioning shop. They are used motor cycle engine valve springs and have just the right tension for the job. They are also the right price as cylinder head shops have hundreds of used valve springs which are just discarded so I got mine for free. New springs would be too hard and would not have the required give for this task.
Coach bolts hold the ball bearing face to the top of the jig and are fixed so that the face of the jig can move when the springs are compressed when the timber is passing through for sawing. Six ball bearing rollers are then fitted to the face in two rows with the first row of rollers sitting about 20mm from the teeth of the sawblade.
I locate the jig and lock it in place with the coach bolts and then clamp the whole jig to the saw table.Using this jig and fence and with correct tension on the blade, I have been able to resaw 360mm wide boards of elm and have a constant thickness along the width and length of the board. The bandsaw I use is a Hafco BP630 from Hare & Forbes and, while not in the class of European bandsaws, it is still a reasonably well made machine.
Tensioning the blade
I don’t have a tension gauge on my saw so I tension the blade in the steps described below. This is done only once when a new blade is fitted. I use the two smaller jigs shown opposite when resawing smaller sized boards. Together, these jigs give the accurate resawing results I need for the furniture I make.
1. Remove the upper and lower blade guides as nothing should touch the blade for this setup.
2. Put tension on the blade and start the machine.
3. Slowly detension the blade till the blade starts to flutter. Now tighten the tension adjuster until there is no flutter on the blade and it runs smoothly.
4. Tighten the tension adjuster another full turn.
5. Mark on your tension adjusting wheel where this is in relation to a set position on the bandsaw. The photo above shows the mark I have on my tension adjusting wheel when proper blade tension is achieved. This makes it easy for when the wheel is loosened two turns for blade de-tension.
6. Refit your guides to manufacturer specifications.
7. De-tension the blade immediately after sawing is finished. I loosen the adjuster off by two turns and then put up a sign to let me know that I have done this so that I don’t turn up two days later and try and wind up the tension adjuster two turns when it is already tensioned.
Raising the lower guides
The guides in their original position.
The 50mm plate is now sitting beneath the guides.
I found that the lower guides on my bandsaw were a long way below the table. The thrust bearing was about 70mm below the timber being sawn which made the guides about 100mm below the timber. I made a 50mm plate to sit the lower guides on which again improved my resawing, as the thrust bearing now sits about 20mm below the timber with the guides being about 50mm from the timber. I used two 25mm pieces of MDF and purchased longer bolts to mount the whole assembly to the bandsaw. This was a very cheap improvement as the only cost involved was the bolts. If you do this modification ensure you isolate the machine from the mains power.
Small resawing jig
I use the jig shown above for cutting thin timbers for bent laminations. Again the idea is that I can get the upper blade guides as close to the timber as possible. This is a scaled down version of the medium jig (see below) using one wheel and a coach bolt for the axle. The small and medium jigs don’t have a guide to sit in the bandsaw mitre track, but are simply clamped in place to the desired cutting thickness. I brace the bandsaw rip fence in place with a clamp and block of wood to prevent any sideways movement of the fence.
Medium resawing jig
This jig is for resawing boards up to 160mm wide. The advantage of using this jig over the large jig for smaller boards is that the upper guides can be set lower and closer to the timber. You can make it from whatever you have lying around the workshop. I used three rubber tyred wheels (available from Bunnings) with a coach bolt for the axle. This is a very cheap jig to make but a very effective one. The rubber tyres have a couple of millimetres of give in them, so the jig can be clamped a bit closer to the fence than the thickness of the timber being sawn. This ensures the timber is held firm up against the rip fence.