Joining two Festool rails

[Jerome Hanby]

There was at least one thread not too long ago discussing the use of two 55" Festool rails bolted together using their extension hardware. There were several posts expressing concerns with the rails actually aligning. Today, I opened up the box containing a second rail and uncorked the extension bars, all of which I bought a while back from a fellow 'creeker. The rails when bolted together were very tight and very straight. I'm not sure anything less than extreme abuse could cause a problem. YMMV, byt it seems to works just fine for me.

[Chris Tsutsui]

Is there a lot of side to side play in the extension bar when it's not tightened up?

Mine has a small amount of play which can translate into a non-straight line if I don't use a straight edge to align the two rails.

This is why I leave a 1mm gap between the rails and then use a straight edge before I tighten up the rails.

[Sam Murdoch]

And I'm one of those who has never, ever had a problem connecting rails - no straight edge checking required :D. Lucky? OK.
My big discovery though was that the straightest lines when using track saws (especially when connecting rails) are achieved by making certain your work surface is FLAT.

[frank shic]

so the garage floor doesn't qualify? ;)

[Victor Robinson]

I hope I have the same luck as you. I just invested in a second 55" rail (with holes!) and hope connecting it to my other one isn't too bad.

[Joe Spear]

I've never had a problem with the joined rails.

[Clint Baxter]

I have at least 7 different rails and have never had an issue when I've joined any of them together. Has anybody here tried replacing the set screws in the rail connectors with an allen head set screw? I've never been enamored of the slotted set screws and would like to replace them. I tend to use them just enough to wonder where I left that screwdriver that fits the screws the best.

Clint

[Ben West]

I have done that, Clint. No problems. I hated the slot set screws.

[Ty Williams]

Link to alternative set screws that don't foul things up?

Also, count me as one person who joins rails regularly with good results. I have taken the time to measure the deviation from straight on several occassions. My worst error so far has been 2 thousandths over 10 feet.

[Bob Reda]

I have at least 7 different rails and have never had an issue when I've joined any of them together. Has anybody here tried replacing the set screws in the rail connectors with an allen head set screw? I've never been enamored of the slotted set screws and would like to replace them. I tend to use them just enough to wonder where I left that screwdriver that fits the screws the best.

ClintI just did that. I've had the two rails for about 15 years now and the only problem is when you break them apart you may lose a screw. I had to tap the one side out to the Nationl pipe thread size then replaced with set screws. It works great.

Bob

[Jerome Hanby]

Mine was tight. Once I had both connectors evened out between the rails and the set screws tightened, nothing moved. I don't have a straight edge that long, but my longest one (Woodpecker) looked like it was dead flat along the back edge...


Is there a lot of side to side play in the extension bar when it's not tightened up?

Mine has a small amount of play which can translate into a non-straight line if I don't use a straight edge to align the two rails.

This is why I leave a 1mm gap between the rails and then use a straight edge before I tighten up the rails.

[Jerome Hanby]

I haven't, but I have thought about it. I'm not fond of the slotted screws. I've got allen head screws in my PSI PPS and other than loosing them all the time, I've never had issues with them.


I have at least 7 different rails and have never had an issue when I've joined any of them together. Has anybody here tried replacing the set screws in the rail connectors with an allen head set screw? I've never been enamored of the slotted set screws and would like to replace them. I tend to use them just enough to wonder where I left that screwdriver that fits the screws the best.

Clint

[Rich Engelhardt]

I tend to use them just enough to wonder where I left that screwdriver that fits the screws the best.
No problem! I just toss that screwdriver into the systainer along with the saw, clamps and connectors.
No problem with the slotted screws either. They only need to be snug - not overly tight. I found out that a half turn is all it really takes to tighten and loosen the screws.

I've only had one time that I can recall where I had any sort of problem with two rails not being spot on.
I chalk that time up to user error.

[Chris Hedges]

There is no need to use straight edge or any complicated tricks to get the rails to align. Simply do what Festool refers to as bridging the gap. On the right side of the saw plate there is a V shaped mark about halfway between front of plate and back. Center this over a small gap left between two rails. Tighten cams on left side of saw and that pulls tracks into alignment! Tighten connectors and your off to the races.

Chris

[Alan Lightstone]

I found that the rails, while they line up reasonably well, don't line up perfectly. For making perfect edges on veneer with my TS55, I had to buy a single long rail. YMMV.

[ian maybury]

It seems to me that it's very much a matter of what you define as a 'problem'. The basic issue is that the two joining rails are placed very close together, with the result that any pressure that tends to knock the halves out of alignment is turned via the leverage created by this short distance into a pretty heavy force that tries to slide one or both rails along its slot against the grip obtained by the screws.

That grip cannot be great, because there are definite limits to how much you can tighten the screws without damaging the aluminium rails. It might work better if there was some sort of a detent hole where the screws bear, but then those holes would have to be very precisely placed and/or the end faces very square or they would simply act to pull the rails out of alignment. Drilling and tapping for some extra holes would probably help too.

That's not to say that it's too hard to get the system to work perfectly well, and the zero clearance and backer-like function of the rail means that it delivers beautifully clean cuts too.

It does tend to mean though that careful handling of the assembly is needed, especially if it's rotated so that the face of the guides is vertical, with the joining rails to the bottom. In that situation it doesn't take much of a bump for the screws to slip and the rails to move out of alignment.

The guy in this video in demonstrating the system precisely explains what's needed to avoid problems - you basically need to (a) ideally work on a flat table so that the joint is not stressed as above, and (b) to frequently check the alignment with a straight edge:

http://www.youtube.com/watch?v=pVFuPfvhHfE&feature=related

That's fine if the sort of work you are doing only occasionally requires long rips. If I was going to set up along the lines that this guy has to use the system for frequent ripping then I'd want to go with the one piece 3m or whatever rail it is that he has too - checking alignment would wear thin pretty quickly:

http://www.youtube.com/watch?v=NiAr7MsMt-A&feature=endscreen&NR=1

ian

[Will Blick]

The screws.... I think they use the fat flat heads, cause they don't want you to over tighten, as the thin metal dimples, which can create problems when the area is all dimpled, assuming you over-tighten, which is easy with allens...

as for the youtube, yep, he uses a long straight edge... I think this is one area where Festool could have been more precise with the 90 deg cuts on the rails...you would think, with two perfect 90's, the joined rails would be dead straight. In my case, they are NOT, unfortunately. But if I tinker with it with a good straight edge, its good to go. Then, set it down on its end too hard, you can change the position without knowing it...like most people, I now use a single rail for all cuts, yes, multi rails are costly, but it eliminated this issue forever. I get tired, and hate to check, re-check, etc. It sounds by the way these posts are going, others got rails which were cut at perfect 90 deg. so the ol, ymmv, might apply here... but these posts make everyone aware of the situation.

[ian maybury]

Working with my set last night I noticed that the end/cut faces are definitely not quite square on them either - with the joint set up using a straight edge and the screws tightened down there's a gap of about 0.25mm to one side....

I'm figuring this could probably be cleaned up and made square on the table saw, but it'd need the cross cut to be very accurately set to 90deg.

ian

[Jeff Monson]

There is no need to use straight edge or any complicated tricks to get the rails to align. Simply do what Festool refers to as bridging the gap. On the right side of the saw plate there is a V shaped mark about halfway between front of plate and back. Center this over a small gap left between two rails. Tighten cams on left side of saw and that pulls tracks into alignment! Tighten connectors and your off to the races.

Chris

Thanks for the great tip Chris

[Will Blick]

Using the saw as a straight edge has limited application. I would only trust this on the shortest rails, maybe... if you join two 4-5ft rails, the errors magnify with distance, the relationship is linear, double distance = double error. The saw is only extends maybe 10" over each rail. When you rip an 8ft sheet, the errors can become very noticeable, specially if you are joining the two edges.... A simple straight edge, even if low cost version is hard to beat...and faster.