Connected rails not staying aligned

[reible]

Hi,

I'm new to Festool but have been woodworking for a long while.  I got the TS 55 saw and rails and have been using the MFT/3 for some projects.  Yesterday I had a full sheet of plywood to break down so I took the rail I got with the saw and the extra 55" rail along with the two connectors as was recommended by the sales guy.  Put it together and thought I was happy.

I attached the two tracks and did an alignment to get them straight, everything looked fine and I did my first cut, a 2" wide full 8' long.  Then started the series of 3" strips.  I checked to make sure they were the correct dimension and repeated the cuts.  When I finished there was a small strip of scrap.  Looking at it I could see it was wider in the middle then at the ends. 

My first and correct assumption was that track(s) were no longer straight.  I wasn't sure if I had some how not had it straight to start but when I stated checking I found that about 3 cuts in the rails had gone out of alignment and the cut was no longer straight but a long curve from that point on.  Checking the tracks verified the arc.

The good news is that this is just a test shelf unit for the garage and  can adjust the design to live with the parts as is.  But I have other more critical projects coming up and need to figure out what I'm doing wrong before I waste expensive wood.

It was a simple cut and index operation and the track was not subjected to being carried about or moved about any more then was necessary.  I checked and the screws were all tight.  I did leave the space between tracks per the instructions.  I still have 5 more upright pieces to cut after I route some dado's in them but I really need those to be right. 

Thoughts about what I did wrong and how to fix it?  (Rather not have to buy the longer track section for this.)  Up to know I've been loving the system!

Ed

 

[tjbnwi]

Most probably side thrust. Takes a little practice to push the saw along without introducing side thrust.

Tom

 

[Svar]

Festool connectors are not that great. You'll have to check alignment with a straight edge repeatedly.

Get better connectors for Makita rails or make your own:http://festoolownersgroup.com/festool-jigs-tool-enhancements/homemade-guide-rail-connectors-(not-your-typical-ones)/msg222492/#msg222492

Some people use this jig and keep it attached over top t-slot and reversed while cutting (not like in the video):

This might also help as you can tighten set screws much harder without digging into the rail:http://festoolownersgroup.com/festo...tool-guide-rail-connector-replacement-screws/

 

[Holmz]

The rails are the bane of the system.
The most sure fire is to buy the long rail.
In second place are the straight edges, betterly system, etc.

(By the time one gets betterly connectors, or the long rail, the could have gotten a different saw and rail system)

 

[Laminator]

Second the suggestion of a longer (3000) rail.  Its the best way to get long strait rips with peace of mind.  Joined rails always makes me check and recheck and recheck....

 

[PreferrablyWood]

I just recount other folks suggestion to get the much superior makita rail connectors..

 

[Svar]

I just recount other folks suggestion to get the much superior makita rail connectors..

Just to clarify, they are superior in a sense that you can tighten them harder, contact point is larger, and aluminum will not give in.

 

[Holmz]

I just recount other folks suggestion to get the much superior makita rail connectors..

Just to clarify, they are superior in a sense that you can tighten them harder, contact point is larger, and aluminum will not give in.

They are not superior in the sense of comparison to a Bosch rail.

But that Betterly connector has somewhat of a Bosch look about it.
At this point you have 3 choices, which include:
1) The 3M
2) checking/setting with straightedges and Betterly type systems.

 

[ear3]

Maybe you're already doing this, but just be conscientious about how you move and reset the rail for each cut, making sure not to stress the connecting point too much.  +1 on the Makita connectors, which I also got to replace the Festool ones.

I know there are plenty of people who have had success connecting rails, but after the first time this happened to me, I went out and got the 3000m rail and couldn't be happier -- even though it made me somewhat poorer.  It's much quicker not to have to break down the setup when switching back between rip and crosscuts.  The only time I join rails now is when I'm doing long rips in excess of 9'

 

[reible]

This has been educational. 

Can't live with it the way it is so I guess throwing some more money at it is my next step.  Being retired finding another $300+ this year would be too much (and I really don't know how I will store a longer rail) so it looks like I will try the Betterley SLC23 StraightLine Connector and either make or buy some different rail connectors.

I was a bit worried about the connectors and when I was at the store I ask about it, the guy said don't worry about it but said he owned the longer rail..... should have been a hint I guess.  Had I know what I do now I would have skipped the extra 55" rail and put the money towards a 106".

I want to thank everyone for your incites.  It would have been a good thing to visit here before I started buy the tools but too late for that.  I do know about the site now so in the future I'll stop here before I go to the store.

Ed