Guide rail speed square... dedicated 90 for crosscutting and shelf dadoes.

[James Watriss]

I dunno, Frank. I bet Festool, or someone else, could make a piece that mates directly to the current extrusions all the way to fitting the slots for the foam rubber strips, and wide enough that it would maintain one-piece accuracy without needing to be made of one piece. Instead of simple T-track nuts in the track on the underside, have a solid steel bar made that is made of stock that's specifically shaped to completely fill that slot, and slides in from the end. Make sure that piece also extends far enough along the rail that it would help to hold the 90 in place when the screws through the fence are installed, with no slop whatsoever. And add a big gratuitous bolt through the hang hole. BAM. Done. As an accessory, add in PSA plastic tape to help the rail slide, to replace the foam rubber and help the rail slide better.

If you really want to get kinky, you could make it compatible with the bridges from the parallel guides for quick-shooting repetitive short cross cuts. Not really concerned about that one, since the original paradigm behind this idea was a sliding rail for quick, from-the-hip shooting, but the thought crossed my mind, so I figured I'd throw it out there.

 

[Qwas]

I've read this thread 3 or 4 times now and I'm seriously considering the challenge.  I agree with James, there is no need to make a new rail or a rail substitute, it will add considerably to the costs (my estimate is it will multiply the final cost by 4).

I'm going to make a prototype in the next week and see what happens. My goals are:

made out of 1/4 inch thick aluminum.
It will be non-adjustable, but accurate out to 48 inches (I will shoot for 1/64 but might have to settle on 1/32).
Be able to attach an optional fence.
Be able to attach  optional adjustable stops.
Be able to clamp to table.
First model will be 16-20 inches long, other models may follow.
A few more options that I'm not going to discuss yet. 
Keep final price under $50.

It will require removing the foam rubber that will be underneath this fence. Removing all the foam rubber is up to you, I don't recommend it since that is what grips the workpiece. I like Michael 's idea of using packing tape if you insist on defeating the foam rubber.

Are you guys serious about buying? Any thing else you want it to do?

 

[Brice Burrell]

....Keep final price under $50.....

If you can do that I'll be your new best friend. Oppps, that might put a stop to the whole project. 

...Any thing else you want it to do?

Yes, shelve snow would be great. No really, sounds like you're on the right track. Very serious about buying one if the accuracy is there. To a 1/64 preferred.

 

[tbellemare]

It seems to me that it would be reasonable to incorporate an adjustment for field calibration like the Parallel Guides have. That way, people can make it as accurate as they please and it could account for whatever tolerances there are in the Guide Rails as their dies wear.

But then again, it might cause the price to balloon.

Tom

 

[score0matic]

I've read this thread 3 or 4 times now and I'm seriously considering the challenge.  I agree with James, there is no need to make a new rail or a rail substitute, it will add considerably to the costs (my estimate is it will multiply the final cost by 4).

I'm going to make a prototype in the next week and see what happens. My goals are:

made out of 1/4 inch thick aluminum.
It will be non-adjustable, but accurate out to 48 inches (I will shoot for 1/64 but might have to settle on 1/32).
Be able to attach an optional fence.
Be able to attach  optional adjustable stops.
Be able to clamp to table.
First model will be 16-20 inches long, other models may follow.
A few more options that I'm not going to discuss yet. 
Keep final price under $50.

It will require removing the foam rubber that will be underneath this fence. Removing all the foam rubber is up to you, I don't recommend it since that is what grips the workpiece. I like Michael 's idea of using packing tape if you insist on defeating the foam rubber.

Are you guys serious about buying? Any thing else you want it to do?

Steve
Nice to see you again, 
I think you could do it fairly simply.  I have been hitting +/- 1/64" with my little square over 4'  so that doesn't seem all that difficult to make a single piece... the utility of one that crosscuts full sheets easly  would be worth the pain of hauling it around.  the only problem would be the addition of the sacrificial strip.....  It is not really a Problem but it is another machining pass.  Besides I felt the need to post

Craig

 

[Qwas]

If you can do that I'll be your new best friend. Oppps, that might put a stop to the whole project. 

Yes, shelve snow would be great. No really, sounds like you're on the right track. Very serious about buying one if the accuracy is there. To a 1/64 preferred.

Brice, We can be friends as long as I DON'T have to make this fence shovel snow. That would require me to go north for testing into blinding white stuff.  [big grin]

I will be shooting for 1/64 accuracy, I just don't want to make that a promise yet, not until I have a prototype working.

 

[peter halle]

I'll throw out an idea for you guys to take as an idea and run with - or dismiss it as bunk.

Besides the rail. the parts are plywood, rare earth magnets, screws, and toggle clamps (optional).

It is based on a 3 -4 - 5 triangle of plywood.  You could add toggle clamps to hold the triangle to the cutting surface - either temporarily while you set your rail and then clamp your rail or if the plywood you choose is less in thickness that the height of the guide rail - while you make the cut.

[attachimg=#]

Just an idea.

Peter

 

[Corwin]

I'll throw out an idea for you guys to take as an idea and run with - or dismiss it as bunk.

Besides the rail. the parts are plywood, rare earth magnets, screws, and toggle clamps (optional).

It is based on a 3 -4 - 5 triangle of plywood.  You could add toggle clamps to hold the triangle to the cutting surface - either temporarily while you set your rail and then clamp your rail or if the plywood you choose is less in thickness that the height of the guide rail - while you make the cut.

Just an idea.

Peter

Peter, I'm not sure what you had in mind for those rare earth magnets -- I don't see how they would assist in holding an aluminum guide rail to the jig...  But, you could route a rebate in the plywood (making an surface that is the same height as the guide rail) to mount a piano hinge to.  That hinge allows the rail to be folded back until the jig is in place -- this keeps those non-skid strips on the underside of the rail from interfering during placement, yet still function when the rail is folded down in place.  I use this arrangement for my home-made parallel guide (that I like very much).

Another part for your triangular-shaped plywood jig would be to add a fence that would locate the jig to the front edge of your material to be cut.  This would be attached on the underside of the triangle section and extend under the rail to the cut line so you could use the end to line up to your mark...

Just some more ideas...

 

[peter halle]

Corwin,

If you slide the rail joiners inside the slot, the magnets will pull the rail to the triangular jig.  The rail joiners don't even need t be fastened.  They are better if they can slide with perhaps the one closest to the beginning end of the cut.  I did test to make sure that even the small rare earth magnets I have stuck to my refrig would attract thru the thickness of the aluminum.

I'm sorry, I didn't explain very well at all.

Your idea of extending the fence / strip under the front of my jig to allow it to get cut the first time is great.  Thanks!

Peter

 

[Corwin]

Oh, thanks for that explanation.  Having made similar jigs using piano hinges as stated above, I never would have thought of using the magnets for that purpose.  My way, the jig and rail are used as one unit.  Your way, the two can remain separate...  Hmmm, something to ponder about.

 

[Corwin]

One last feature for Peter's plywood triangle design is to drill some large (maybe 2" or so) inspection holes through the triangular piece before attaching the lower fence piece.  These holes in the upper piece are centered along the line where the fence meets the material to be cut.  In use, you would look through these inspection holes to verify that the fence is tight to the material -- without such inspection holes you cannot see from above that your jig is positioned against the material.

 

[PaulMarcel]

To answer Qwas... I'd definitely buy it at the $50 price point.  Have a bunch of your dogs and rail dogs and love the quality.

 

[James Watriss]

Rail joiners!

So, delete the part I wrote about making a piece of steel to replace the t-track nuts. Insert instead that the fence should bolt to a rail joiner.

Off the shelf parts are cheaper than custom made.

 

[peter halle]

As an expansion of Corwin's comments, if you were to make the bottom fence thicker than the material that you normally cut, and let it extend past the track - see below diagram - then when you cut the first cut your kerf will mark both sides of your cut.  Handy if your good piece is on the right.

Set up the jig to your cut line.  Toggle clamp in place.  Slide rail over to the side of jig.  Cut.  Something like that.

[attachimg=#]

Peter

 

[Corwin]

As an expansion of Corwin's comments, if you were to make the bottom fence thicker than the material that you normally cut, and let it extend past the track - see below diagram - then when you cut the first cut your kerf will mark both sides of your cut.  Handy if your good piece is on the right.

Set up the jig to your cut line.  Toggle clamp in place.  Slide rail over to the side of jig.  Cut.  Something like that.

Peter

Your diagram looks good. but I see no reason for your statement about the bottom fence being thicker than the material.  When using this jig on material thinner than the bottom fence you will need to position the material slightly over the edge of your cutting table so the fence locates off that edge of your material and not the edge of your cutting table.  Otherwise, all you need to add is a handle.
[thumbs up]

 

[peter halle]

Corwin,

Lets say that I am cutting .75 inch thick plywood.  I have the plywood set on top of a foam sheet and extending out .5 inches over the edge.  I have my TS saw's depth set to cut 1/8 inch into the foam sheet when I make my cut.  The bottom fence extends 8 inches past the square end of the jig.  I slide the triangular jig to the edge of the sheet so that the fence touches the plywood.  I cut.  The fence - if it is thicker than the material being cut by more than that 1/8 inch will now have an indexing kerf that will allow me to line up the jig quickly for any cut.  Before i even set the rail on the wood.  If I want the good to be to the right, the kerf indicates the mark.  Same if the good is to the left.

Maybe this will be better than my explanation:

[attachimg=#]

Peter

 

[score0matic]

Peter,

I like the idea I think a 24" x 24" 45deg would be enough to provide the accuracy needed .

The fence - if it is thicker than the material being cut by more than that 1/8 inch will now have an indexing kerf that will allow me to line up the jig quickly for any cut.  Before i even set the rail on the wood.  If I want the good to be to the right, the kerf indicates the mark.  Same if the good is to the left.

There are a couple of major drawbacks to this idea when you try to use it in the feild, 

• the sheet to be cut must be over the edge of the substrate otherwise you could make the square off 90 deg....even if you use the index holes....
• once you make the index kerf you will weaken the fence.  Any "jobsite" handling will bend or break it  there.  once your right side index is broken there is no reason to have it thicker than the substrate

I agree that having a ready reference to the right side is useful  but i think your solution is good on paper,or sketch up [thumbs up], but will prove frustrating in action.

Craig

 

[JayStPeter]

My solution is HERE.  There are some other decent ideas in there also, especially WRT making the angle unit work.

 

[John Stevens]

Guys,

FWIW, Festool seems amazingly precise when it comes to the dimensions of its extrusions.  Tonight I checked the end of one of my guide rails with an 8" drafting triangle, and as far as I could tell, it was dead-on at 90 degrees.  It seems to me that it could be pretty easy just to register a straight piece of wood right off the end of the guide rail.  As long as it has parallel sides, it'll present a face that is 90 degrees.  Make it about 100mm/4" wide in order to give enough room for blade clearance before you run out of rail.  I'd cobble one together to try it out, but I've got too much picture-rail molding to install before I can start fiddling around with anything like this.  :'(  I love to design furniture, I can tolerate making it, but I just can hardly stand carpentry.

Regards,

John

 

[James Watriss]

Guys, I understand the magnet idea, but I'm more interested in Qwas' project. I'm looking for something that bolts up and acts as a solid unit. Not something that holds with magnets. I'm not saying they wouldn't work. But I trust something with a solid mechanical connection more.

Qwas, I'm down. If you can break the $50 price point, absolutely.

I'm laying that bid down on what I think is going to be a simple aluminum fence that mates to the bottom of the track, most likely bolting directly into some rail connectors. Find a better solution, I'm all ears... this one is your baby. I'd be pretty retarded to pass on something I started a thread for. Go for it.