# True rack and pinion fence



## David Peebles (Feb 17, 2012)

Several years ago, I bought a well-used Unisaw. It had the standard fence rails front and rear, but the fence was somewhat discombobulated. This was fine with me, because I had long harbored a notion to build a true rack and pinion fence (somewhat along the lines of DW’s portable contractor’s saw). From Applied Technologies I bought gear racks and pinion gears. From my local hardware store and steel supplier if found a drive shaft (to connect front and rear gear pinion gears), and steel square tubing in sizes that would slide inside each other. The fence I made from a 2X3 aluminum extrusion from my nearby metal recycler, with latches at each end for easy attachment/removal. It worked better than my fondest wishes. The features are as follows:
The fence (once adjusted) is always parallel to the miter slot. You can grab the fence anywhere along its length, and push or pull it to any position without binding. Normally, however, it moves via pinion gears and hand wheel (which serves as a crank).
The rails telescope, which means that when not being used, the saw is but little wider than the basic table with wings. It could be made narrower (but no reason to), or wider.
There are three attachments along the rails for the fence: extreme left, extreme right, and middle. This gives about 23” from the left of the blade, and about 43” to the right of the blade. Of course a few inches added to the rails (and the gear racks) would easily provide 48” inches or more to the right of the blade. Capacity to the left of the blade could also be increased.
Since the fence might move inadvertently, I put on a cam-lever arrangement to lock it, similar to the fence lock on a T-square fence.
Thinking it might be useful to have a means of extremely precise fence positioning, I worked out a worm-and-right angle drive that should be able to position the fence within a few thousandths of an inch (I myself am not that precise a woodworker). My prototype was extremely crude, the worm being the knurled adjuster off an old crescent wrench; this worm didn’t even fit the straight-cut pinion gear I tried to match it to, but it did work (though not well). I have since cannibalized the worm and pinion from an old Delta blade sharpener (the kind with the 8" horizontal wheel), and have made a replacement, but won’t install it until I do that tune up and tweak. This thing has a sort of clutch so you can engage/disengage it simply with a push or a pull.

Advantages: For my space challenged shop, it is a great asset to be able to keep the saw compact except for those occasions when I need greater capacity. The system has proved to be more reliable and consistent than I could have wished for. It is very reassuring to know I can position the fence anywhere, and after measuring from the blade, know that the far end will be right on. After about 4 years, I am just now beginning to think that it needs a bit of tweaking and tuning up, primarily to ease movement with the crank and confirm parallelism. Locking the fence down doesn’t cause a slight shift in fence position, as sometimes happens with T-square fences (and some of them are very bad in this regard).

Disadvantages: I used hardware store draw hasps to attach the fence each end. Slots engage with registration pins to give precise positioning along the rails. I am not in love with this arrangement as they are not “elegant.” (My definition: when you look at it you say “Of course, how could it have been done any differently?!”)
The bushings for the drive shaft are on makeshift adjustable brackets, which are rather crude, though to my surprise they have not required frequent adjustment (I’ve done it only once or twice). The process is fussier than I like, but seems to work okay.

So here’s my question for all you woodrats: would such a system appeal to you? Would you be willing to pay a premium for it, either as optional equipment on a new saw, or as an add-on to an existing saw? Would you prefer to build your own system, if plans were made available (you’d need to have basic welding skills, and be able to cut metal, such as with a thin metal-cutting abrasive blade in an angle grinder, maybe a metal cutting bandsaw, and of course have a drill press for obvious reasons). I’m curious as to your reactions.


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## dodgeboy77 (Mar 18, 2009)

I'm sure we'd like to see pictures!

Bill


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## PSDkevin (Dec 18, 2010)

I can only speak for me. It would appeal to me but for me it'd be tough to buy a finished product without a ton of reviews depending on price point. The beam style is a pretty proven formula and one most are used to. But a kit....or plans... you now have my attention. In fact with a few more questions I'd be willing to spend a bit on the plans for the thing today. I'm getting a welding degree and sounds like a project I'd love. Just my two cent.


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## David Peebles (Feb 17, 2012)

*Rack & pinion fence*

I will get some photos up, but first I have to clean up my shop. Going to take a while. I understand the hesitation about buying anything without reviews--but first there has to be a product to review, which there isn't. I've thought about taking it to Grizzly (I'm in the fortunate circumstance of living in Bellingham, WA, which is Grizzly's home base. They started here somewhere around 1984.) But plans--that is something I could do. This thing is certainly within the capability of anyone who can cut and weld metal (I myself am self-taught on a wire welder; as you can imagine, you can't become an expert with such an incompetent instructor)


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## Shop Dad (May 3, 2011)

+1 pix

Sounds like an interesting idea. I think you would need to handle in a similar way to how the guys making the Bolt On Ripping Knive (BORK) or the Shark Guard handle production and marketing. Take a look at their offerings and maybe even talk to them about their experience bringing products to market. I'm sure some would be perfectly happy with plans alone while others would need a kit or even finished product. I think your challenge will be to keep production costs (and time) low and make it valuable enough for someone to buy at a price that makes you money. With some success you may be able to sell your design and brand to a larger company who can mass-market them. Good luck!


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## woodnthings (Jan 24, 2009)

*My fence experience...*

Besides sitting on it goes like this: Early Craftsman rack and pinion, later Craftsman slide and glide and turn the long knob CW to lock, shop built aluminum with a CW twist knob to lock....then Biesemeyer and a Unifence, both with cam locks.

So I'm very used to slide and bump then measure or use the tape on the fence rail. It's quick not always self squaring unless locked, but for the most part very accurate and workable.
Now would I like a "fine tune" capability to get her just right on the money...you betcha. Do I want to replace all my fences? NOPE. So that's where I'm at. Maybe a micro adjuster which is better than the Rockler magnetic unit which I feel for on sale and broke when it dropped on the floor. The magnetic part is fine, but it was a push only and if you went too far there was no way to go back. :thumbdown: bill .02C


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## diane-mooregear (Mar 8, 2012)

If you go the route of making plans available, I will sell gear racks in small quantities to individuals and help you avoid buying through a distributor.

[email protected]


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