Author Topic: Rip gauges.  (Read 6590 times)

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Offline MichaelM

  • Posts: 41
Rip gauges.
« on: August 11, 2008, 03:23 PM »
I have spent a great deal of time thinking and designing rail positioning gauges to meet the unique challenges my shop (11X18ft with a 6' 8" ceiling) and business provide. Johne's beautifully simple gauges ( provide much of the inspiration for the design that follows, with some changes.

I run a small remodelling business, focusing on millwork and cabinetry (if I could make a decent living do just this I would.) I quickly realized a couple of things soon after purchasing the Festool system with regards to the guide rail:

1.   The guide rail splinter guard works well when freshly cut, as a positioning tool but too slow to be economically practical.
2.   The splinter guard does not last very long once cut (particularly when working with PB core laminate sheet goods.) So as to make using it for both of its intended purposes useless (I?m working on the longevity of the splinter protection.) Again this lack of exact splinter protection is really only an issue with PB core laminate sheet goods or when trying to use it to align the guide rail.

As such I am inclined to leave the splinter guard in place (as is) whenever possible (i.e. when not working with PB core laminates); this would mean I would need a method of placing the guide rail in the correct position without relying on it.

The following gauges are probably a version 6 or 7 of the line of designs I have. They have the following benefits (possibly more):

1.   They are very economical to manufacture and parts are readily available
2.   They are easy to manufacture and require no critical measurements (though some precision is required in making them)
3.   They can be zeroed exactly to the left OR right of the blade
4.   They can be used to position the rail with the off cut either under or to the right of the guide rail (as per normal Festool convention) Which means they can be used to perform rips cuts as narrow as 30mm (or narrower with a spacer block or re-design of the stop rest.)
5.   They are small and lightweight, and are easily removed out of the way (at one time considered a drawback but now I think it is mandatory in my tiny space, a 118? guide with permanently installed gauges was just to unwieldy.)
6.   Only one needs to be set to the tape the second can simply ?copy? the length
7.   They are self contained and with the exception of the zeroing accessories (known width of wood) require no other tools to use (assuming a minimum desired rip of 30mm)
8.   Loved Johne?s idea of a simple friction mount but wanted something that would continue to provide friction so I added "cam" screws (like the Incra mitre bar does)
9.   They eliminate measuring and marking
10.   They work

They have the following draw backs (possibly more):

1.   They must be removed prior to making a cut (this is actually no longer considered a drawback by me, see point 5 above.)
2.   Milling of small wooden parts during manufacture can be tricky
3.   I loved Johne's idea of being able to use his design as story sticks to match an existing cut piece of wood. I believe it is possible to make these units work this way but I have not figured that out yet.
4.   It must be re zeroed when switching the off cut from left to right of the rail

I have added photos below of the finished design and product. Please feel free to critique and or provides tips on how these can be improved. The measurements on the design are how they worked for my unit I can't promise they will be exact to your gear. PLEASE confirm them if you decide to make these.



« Last Edit: August 14, 2008, 01:32 PM by MichaelM »

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Offline MichaelM

  • Posts: 41
Re: Rip gauges.
« Reply #1 on: August 14, 2008, 01:35 PM »
A couple more pics.

Offline Rey Johnson

  • Posts: 390
  • Fine Sawdust Maker
    • Festool MFT/TS55 Retrospective
Re: Rip gauges.
« Reply #2 on: August 15, 2008, 07:13 AM »

Thanks for the posts here. You have some really good ideas!! Great photos.

I have a few questions though:

1. Are the measuring heads completely independent? If so, is it a tedious process to get both sides measured exactly? It seems that even a very small mismatch in measurement between the two sides would be magnified over a long rip.

2. Since you have to take the gauges off for each cut, do you have exact repeatability when you need to cut several narrow pieces?

3. When your off-cut is to the left of the rail, how do you ensure that the workpiece is and stays perpendicular to the rail?

Also, do you have any pics of the gauge with a workpiece and showing the entire mft, or a larger portion of the mft. I'd like to see the gauge within full context of the mft.

All in all, great post. Thanks for sharing.

Offline Matthew Schenker

  • Posts: 2619
Re: Rip gauges.
« Reply #3 on: August 15, 2008, 07:36 AM »
Thanks for the posting!  This concept of rip gauges has been one of the most sought-after of all the Festool-related jigs.  Some might even call this the holy grail of Festool jigs!  Actually, the idea of a rip gauge was one of the original inspirations for the forum, way back to the old Yahoo days.

I'd love to see more about this, and see how it's used in actual projects.

Thanks again for taking the time to build this, and share it here.

Stay in touch,
FOG Designer and Creator

Offline MichaelM

  • Posts: 41
Re: Rip gauges.
« Reply #4 on: August 15, 2008, 11:14 AM »
My Pleasure! Thanks.

Matthew, yes I recall the discussions on the old forum and posted a rather elaborate design back then, that mounted to the bottom of the rail. That design did not work practically. I think that was version 2 or 3. It also had way to many parts. I have been trying to simplify ever since.

Rey, the photo with the square butted up against the gauges is me duplicating the measurement. Its quite simple:

1. I first set the measurement on the main gauge.
2. Loosen the second unit and place the square next to it as shown, the stock of the try square is touching the main gauge stop.
3. Move the second gauge bar over till it touches the stock of the try square.

You are right about the potential for error. So far over the longest rip I have done (4 feet) I have achieved exact cutting (or at least as far as I can measure.) The key is to ensure the the stops are of the same dimension. Particularly the thickness of the actual lip that touches the work piece. I am looking at re-designing the stop using a round stop pin as that would eliminate another potential for error which is material (dust, chips) getting sandwiched between the existing stop lip and the work piece.

The current length of the gauge arms (36") are best suited to the original design intent (ripping sheet goods down for cabinets.) I would make a couple of much shorter gauge arms for frequent narrow rips (or regular use on the MFT.) With a 118" long guide rail there is no movement when removing them, due to the weight of the guide rail.

I will post some pics later of the gauges on a larger work piece as well as how they can be used on the MFT. Finally I post further on how they are zeroed.



Offline MichaelM

  • Posts: 41
Re: Rip gauges.
« Reply #5 on: August 15, 2008, 02:47 PM »
How to zero the gauges. Photos illustrate zeroing for off cut to the left of the rail first. Then off cut to the right of the rail.

The last photo shows the gauges in the off cut to the right of the rail position.

Offline John Stevens

  • Posts: 816
  • Ardmore, PA
Re: Rip gauges.
« Reply #6 on: August 15, 2008, 09:41 PM »
How to zero the gauges.

Michael, would a gauge like this speed the process?

The dominos butt up against the left edge of the rail.  (Instead of dominos you could use a pair of nails, screws, dowels, whatever.)  Leave it a little wider than the guide rail and make a shallow scoring cut with the saw to indicate the right-most edge of the cut.  Hope this helps.


« Last Edit: August 15, 2008, 09:44 PM by John Stevens »
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Offline MichaelM

  • Posts: 41
Re: Rip gauges.
« Reply #7 on: August 16, 2008, 06:39 PM »
I have been trying to think of something similar to those gauges. For quicker zeroing. Though it takes a lot longer to read through my previous post then it does to actually perform the task. The nice things about always using the combo square is:

-I always have one on me.
-I am always measuring from the blade currently installed

Having said that I am going to try to adapt your gauges some how.