Joining guide rails accurately.

[Peter Hamilton-Scott]

Today I joined two guide rails using the interlocking bars. I noticed that there was a little bit of movement where the two rails come together. That got me thinking that if I cut along the rail there might be a slight angular error where the saw transitions from one rail to the next at the point where they join. True, the angular error is very slight but if, as a purist, I want to ensure the cut is absolutely as straight as possible how would I do that?

I tried using a third rail's edge and aligned the two rails I was joining against it and that seemed to stabilise the join before I tightened the screws. Is there a better way of ensuring a direct transition from one rail to another that you can suggest? I know my idea is practical but perhaps you have other suggestions?

 

[PeterK]

I have two of the 55" rails and always questioned the alignment as there is some slop in the connector bars. Like you, I put it up against another known straight edge to try to be accurate. Also, tightening the screw easily deforms the aluminum rail surfaces. Would really like to have the long rail but dang it is pricey. Of course shipping and packaging an item that long is a lot of the price. Pete

 

[Brice Burrell]

I made a fun little animation of the alignment process I use, check it out here on my website.

 

[Administrator_JSVN]

Nice animation, Brice.

An alternative, called the Bridge Method, is explained in another thread.  That thread discusses connecting guide rails and may be a good reference as well.

http://festoolownersgroup.com/index.php?topic=4160.msg70987#msg70987

 

[Dan Clermont]

I concur with Brice's method and use a 4 foot level to ensure my rails are straight

Dan Clermont

 

[TheToolPlace]

I made a fun little animation of the alignment process I use, check it out here on my website.

Brice,

Very impressive animations on your website.  What program do you use to make them?  How long do they take to make?

Keep up the good work.

Thanks,

Chad

 

[Brice Burrell]

Brice,

Very impressive animations on your website.  What program do you use to make them?  How long do they take to make?

Keep up the good work.

Thanks,

Chad

Chad, I built models in SketchUp! then with a series of pictures made gif images to make the animation. Since I already had the rail model it didn't take long to make the animation, maybe a half hour. 

Nice animation, Brice.

An alternative, called the Bridge Method, is explained in another thread.  That thread discusses connecting guide rails and may be a good reference as well.

http://festoolownersgroup.com/index.php?topic=4160.msg70987#msg70987

This method works well for aligning the rails at the intersection but doesn't guarantee the rails are in a perfectly straight line over the entire length of the rails, especially when joining longer rails. A long level gives you a much better shot of getting things straight.  

 

[score0matic]

I made a fun little animation of the alignment process I use, check it out here on my website.

Brice you have way too much time on your hands .  but at least you are not animating your festool drill (with proper clutch settings) securing the screws.
craig

 

[Brice Burrell]

Brice you have way too much time on your hands .  but at least you are not animating your festool drill (with proper clutch settings) securing the screws.
craig

Yeah, I don't have kids so as you can imagine I've got some time on my hands to have fun.

 

[WarnerConstCo.]

I just butt them together and tighten the screws up.

Worked a few hundred times so far.

 

[Brice Burrell]

I just butt them together and tighten the screws up.

Worked a few hundred times so far.

I've found the rail ends aren't always perfectly square so when you join them you don't get a straight line.

 

[Corwin]

Using a straight edge to align the back side of two rails should work in most cases.  You may, however, have two rails that differ slightly in the distance between the back side and the raised 'hat' area that the tool locates to.  Most rails are very, very close to being identical, yet I have seen rails that differ as much as .007" -- not bad, but still a bump in the road.  The 'bridge' method will align the rails by the hat area instead of the back edges, thus eliminating this potential problem.  Joining rails that differ a little can also be accomplished as Brice illustrated, but also using two feeler gauges between straight edge and back edge of one rail to offset as needed and align the hat area.  Again, the guide rails are typically very consistent and this type concern is not the norm.

 

[danrush]

I just butt them together and tighten the screws up.

Worked a few hundred times so far.

I've found the rail ends aren't always perfectly square so when you join them you don't get a straight line.

I too have found one or two of my guides not sqare at the end.  Pretty easily fixed though.  I just put them in the chop saw and squared them.  I just butt the ends and attach the rails.  For most applications, anything else seems redundant.  In the real world, a 110" rail that MAY have a bow of 1/132" or even 1/64" does not really mean much.

Dan