Vacuum fence system for resawing on a table saw

[John Huber]

I needed some ¼” x 2 7/8” x 30” slices of walnut to edge some veneer panels. After an accident that earned eight stitches and three weeks out of the shop, I had some time to find a safer way. Here it is.
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The system controls the location of both the keeper slice and the offcut in all three directions: up-down, parallel to the blade, and perpendicular to the blade. With my Forrest Woodworker II blade carefully aligned to the fence, there is less than 0.010” fluctuation across and along the as-sawn slices. A little sanding and they are ready for finishing.
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The vacuum fence is a stack of four 1” square by 48” aluminum extrusions epoxied to hardboard. These extrusions are very straight and uniform. At first the holes were 1/8” but the vacuum from a 1 ½” shop vacuum was too great and a board couldn’t be pushed along it. By incremental trial, 3/16” holes gave a balance between clamping force and sliding force. There is an in-feed support shown on the right. The vacuum port is a crevice tool epoxied into an oblong hole and reinforced with brass pins. It is located between the saw and the infeed support. If I had it to do over, I would shift the fence to the left and add an outfeed support.
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The pusher is basically a long, tall, narrow version of Micro-Jig’s GRR-Ripper system for ordinary ripping. The two pushing handles are mounted to a mini-track because I wanted to be able to adjust their location for best pushing control. For extra control, I added a sacrificial block to the back of the pusher. The thin finger on the right is the pusher stop for the keeper. The wide finger on the left is the pusher stop for the offcut.
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Resawing gets tricky when the workpiece is taller than it is wide. Then both the keeper slice and the offcut are hard to control. This pusher firmly presses both the keeper and the offcut down onto the saw table. The vacuum fence firmly grasps the keeper. The splitter keeps both keeper and offcut from closing on the rising rear of the blade. The pusher stops secure the workpiece in the pusher. All I need to do is push. All alignment and kickback issues are handled by the resawing system. It works a lot like the meat slicer in a Deli.

[Julio Navarro]

Looks interesting, John. Can you post more pictures, maybe one in action?

[John Stevens]

Thanks for sharing your ideas, John. I'm fairly new to woodworking, and have only resawed on a tablesaw a couple of times. I understand the risk of kickback from the piece that lies between the blade and fence, so I see the value of your vacuum device.

However, I don't understand the risk of kickback from the piece on the left side of the blade. Hence, I'm unsure of the advantage of your pusher over an ordinary push stick.

One other thing I don't understand--are you cutting through the whole work piece, from bottom to top? If so, I assume you're doing it in multiple passes, but are you not flipping the work piece edge-for-edge? I thought that was the way to do it in order to minimize heat buildup and maximize safety. Your thoughts?

Thanks in advance to John or anyone else who wants to chime in.

[Julio Navarro]

cutting small peices on the TS has been the most challenging cut for me. One big problem is keeping ahold of the thinner cut. John seems to have addressed that with the vacuum side of his 'fence'. Its one thing to control one part of the cut but how do you handle the other? Vacuum sounds like a good solution.

The only question I would have is how do you control the degree of streangth of the vacuum from specie to specie. Some are harder to cut requiring more push than others which would in turn mean stronger vacuum hold. If there was a way to 'dial' the vacuum volume, if I may use that term, then I can see it being universal. Perhaps a one fits all vacuum is all thats required.

Have you thought about moving the vacuum fence along with the cut peice, sort of like a movable guide that slides along while holding the smaller peice?

Would it not be easier to use a bandsaw to cut thin peices?

It's a very interesting solution, John. I look forward to more pictures and reports on its performance.

[John Huber]

Looks interesting, John. Can you post more pictures, maybe one in action?

Hello Julio,

There's not much to see when the system is in action. The wood and blade are completely covered.

[John Huber]

Thanks for sharing your ideas, John. I'm fairly new to woodworking, and have only resawed on a tablesaw a couple of times. I understand the risk of kickback from the piece that lies between the blade and fence, so I see the value of your vacuum device.

However, I don't understand the risk of kickback from the piece on the left side of the blade. Hence, I'm unsure of the advantage of your pusher over an ordinary push stick.

I got the eight stitches when a narrow push stick slipped into the blade and was hurled into my hand at 150 mph. The pusher eliminates this risk. As you say, there is not much risk of kickback from the offcut. But the pusher keeps a thin offcut from flopping around and banging into the upper part of the blade.

One other thing I don't understand--are you cutting through the whole work piece, from bottom to top? If so, I assume you're doing it in multiple passes, but are you not flipping the work piece edge-for-edge? I thought that was the way to do it in order to minimize heat buildup and maximize safety. Your thoughts?

The system is intended to cut the whole workpiece from bottom to top, and not flipped. I've had no problem with heat buildup. Depending on how well the saw blade and fence are aligned, the flipped method can leave a ridge that needs to be planed flat.

Thanks in advance to John or anyone else who wants to chime in.

I guess I'm not intending to say other methods are bad, just that this is an alternative that suits me.

Best regards, John

[John Huber]

cutting small peices on the TS has been the most challenging cut for me. One big problem is keeping ahold of the thinner cut. John seems to have addressed that with the vacuum side of his 'fence'. Its one thing to control one part of the cut but how do you handle the other? Vacuum sounds like a good solution.

The only question I would have is how do you control the degree of streangth of the vacuum from specie to specie. Some are harder to cut requiring more push than others which would in turn mean stronger vacuum hold. If there was a way to 'dial' the vacuum volume, if I may use that term, then I can see it being universal. Perhaps a one fits all vacuum is all thats required.

Have you thought about moving the vacuum fence along with the cut peice, sort of like a movable guide that slides along while holding the smaller peice?

Would it not be easier to use a bandsaw to cut thin peices?

It's a very interesting solution, John. I look forward to more pictures and reports on its performance.

Hello Julio,

I haven't tried cutting softer woods, so I don't have a certain answer to your question. However, the sliding friction of the keeper on the vacuum fence feels stronger to me than the resistance from the saw blade. So maybe there isn't a big difference in species.

I did think about having the vacuum fence moving as a sled. Others have posted systems that do that. It seemed to me there were two problems. (1) How to ensure the vacuum hose didn't get hung up and botch the cut. (2) Any moveable system must have clearance and so maintaining the keeper's thickness accurately across its width and length could be a problem.

Most people seem to resaw on a bandsaw. I don't have one. In other posts, it seems that blade wander is a problem for bandsaws. I haven't seen any figures on their holding the keeper thickness accurately.

As I mentioned in another reply, I'm not saying other systems are bad. I'm saying this system is one that seems to suit me. No blood so far!

Best regards, John

[Julio Navarro]

I think its a great idea. All your points are good ones.

Just as it takes many different machines to cut the same peice of wood it takes lots of good ideas to use those machines.

I'd like to see more pics.

[John Stevens]

If there was a way to 'dial' the vacuum volume, if I may use that term, then I can see it being universal.

Festool vacs are adjustable that way. You could also use a valve on the hose (or in the jig), sort of like household vacs have.

[John Huber]

I think its a great idea. All your points are good ones.

Just as it takes many different machines to cut the same peice of wood it takes lots of good ideas to use those machines.

I'd like to see more pics.

Hi Julio,

Sure I can post more pics. What would you like to see?

Best regards, John

[Julio Navarro]

The vacuum attachment

[John Huber]

The vacuum attachment

Julio,

Here's the vacuum port, seen from below and the left (blade) side. It is important to cut the oblong hole in the aluminum extrusion to fit the crevice tool closely. The epoxy might not fill a large gap. The two brass pins are to reinforce the joint so that any rocking stress on the crevice tool won't break the seal. The "mouth" of the crevice tool extends into the aluminum extrusion about 1/2" so the pins are at least 1/4" inset from the end for strength. Also there is a 3/4" port here in both the lower two extrusions to apply vacuum to the upper row of holes.

Hope this is what you wanted,
John

[Dennis McDonaugh]

I always cut thin pieces like that on the band saw, then run them through the planer because I don't like cutting them on the table saw.

[Steve Beadle]

Very interesting, John. Thanks for the ideas.

Have you thought about some way to open/close ports between the vacuum chambers, so that you could have suction higher up on the fence, for taller workpieces? I'm thinking of some way to open up the 2nd and 4th levels, while closing off the 1st and 3rd. There might be some situations in which that might be desirable.

Thanks for the mind-provoking!

Steve

[John Huber]

Very interesting, John. Thanks for the ideas.

Have you thought about some way to open/close ports between the vacuum chambers, so that you could have suction higher up on the fence, for taller workpieces? I'm thinking of some way to open up the 2nd and 4th levels, while closing off the 1st and 3rd. There might be some situations in which that might be desirable.

Thanks for the mind-provoking!

Steve

Hello Steve,

Yes, I did think about having suction on the upper levels. Here was my thinking; it might be wrong. If the workpiece is perfectly flat, there is no advantage to having suction at the upper levels. If the workpiece is not perfect, having suction at the upper levels might pull the workpiece away from the lower levels, create extra leakage, lower the overall vacuum, and cause the workpiece to release from the fence altogether.

However, I had not thought of being able to select which level had vacuum, as you suggest. That might be desireable sometimes. I haven't given any thought to a selector system.

Best regards, John