Better guide rail attachments?

[smorgasbord]

With my CNC, I've gone down the path of making accessories for the now-defunct Inca line of tablesaws, once made in Switzerland. Things like new insert plates and miter bars (they use a 20mm T bar that's non-standard).

I'm wondering if there would be a market for a better-designed/built guide rail joining system. I hear the Makita is the best, even though Festool's second generation is improved. Unfortunately, I'm not yet a track saw user (it's on the to-buy list).

I'm soliciting ideas for better guide rail attachment joiners. I can machine aluminum, although I've found that using Delrin often has a lot of advantages when absolute strength isn't paramount. The self-lubricating qualities mean a tighter fit than with aluminum can be possible, and I think it's even more stable with temperature changes. I know people complain about grub screws leaving marks on the rails, but there are also, I believe, alignment issues that require specific procedures to perform when assembling to have the rails in line with each other.

I'd like to hear what's wrong with the existing solutions, what can be done to improve them (I think I read that combing one piece from Makita and one from Festool is optimal, if expensive), and any other ideas people have. Maybe it would be possible to come up with a new design that I would share freely, and perhaps manufacture for interested woodworkers.

 

[mino]

...
I hear the Makita is the best, even though Festool's second generation is improved. Unfortunately, I'm not yet a track saw user (it's on the to-buy list).
...

There is no "best" system. And there will never ever be.

Any self-aligning system has inherently limited precision (due to the small connector contact with rail) but can be "auto-magical" on the other hand.
Any non-self-aligning system is inherently very fiddly (alignment using a reference straight edge is a must) but can be even more precise than a single rail. In theory.

An ideal system would be both super-precise and non-fiddly. These are mutually contradictory properties, however.

...
Makita is not "the best". But it is non-denting (so potentially strongest) and is non-self-aligning, meaning it can be aligned using external reference straight edge, thus allowing for maximum possible precision .. at maximum fiddling need.

The Festool new self-aligning connector is probably as good as it gets, design-wise, and I am pretty sure it is patented. (So 20yrs till others can copy it.)

The TSO self-aligning ones approach it a bit differently. Between them, these likely cover all the options how this can be done.

Also, the Makita connector is, I believe, still under patent protection as it is less than 10 yrs on the market ..

Between these three, there is not much that can be invented. At most, someone could make a bit better-looking Festool ones, but that is just the  aesthetics side really.

ADD:
For self-aligning the "best" setup, functionally, is the Festool self-aligning one or one of the TSO ones each combined with a Makita one for strength in the top slot. But the problem is these use different hex drivers ... so one better plan to re-thread the Makita one for this to be practical .. heh.

For non-self-aligning, Makita ones rule and there is nothing that can be really done to improve upon them. Even the use of a 2 mm hex there is actually good as it prevents damaging the rails by over-tightening.

 

[woodferret]

I find that dealing with floppy heavy rails, even the TSO / New Festool gets slightly out of alignment unless I want to crank the aluminum to almost deflection point, which I do not relish.  Ended up getting a Betterly to ensure the two rail halves are still in line when I flip them about to tighten.

When breaking down goods, these two default connectors are good enough.  If you need hyper precision, you're not going to get it from such a small contact area with such a large moment arm.

P.S. Aluminum is a crappy metal.

 

[mino]

I find that dealing with floppy heavy rails, even the TSO / New Festool gets slightly out of alignment unless I want to crank the aluminum to almost deflection point, which I do not relish.  Ended up getting a Betterly to ensure the two rail halves are still in line when I flip them about to tighten.

When breaking down goods, these two default connectors are good enough.  If you need hyper precision, you're not going to get it from such a small contact area with such a large moment arm.

P.S. Aluminum is a crappy metal.

I would say try getting a Makita set and use the top slot with a tightened Makita connector for strength .. as the self-aligning ones must not be over-tightened. But you already have the Betterley setup ..

For me, I use a 3rd (1400) rail clamped as a reference when needing max precision .. with the Makita connectors this works great as one of them is strong-enough to afix the rails for rotation, second fixes it for good afterwards. They are also painted, which works as anti-slip inside the slot.
I do hate the old-style Festool connectors with a passion .. precisely because they cannot be properly tightened without damaging the rails. This includes the one shipping with the self-aligning one. Festool should have licensed the Makita solution to the problem there.

 

[Hotwheels]

Are the Festool Self-Aligning connectors as good as or better than the TSO connectors?

 

[mino]

Are the Festool Self-Aligning connectors as good as or better than the TSO connectors?

Depends.

The Festool strong points vis-à-vis TSO:
- only one connector is self-aligning, this means a potential for better accuracy
- the self-aligning connector is "stressing" the rail in a way where it is the strongest, allowing for connection that is a bit more stable than the TSO one

The Festool weak points vis-à-vis TSO:
- the non-self-aligning second connnector is still the rail-denting type, limiting how much it can be tightened and thus counter-acting on one of the strong points above

Overall, the Festool setup is a bit more accurate (by design) but also a bit more fiddly/tricky to operate - the tighening of the connectors needs to be well-measured and is different between the two connector types in use.

If the secondary connector was a Makita-style, or at least used TSO-style screws, the Festool would have a clear win. As it is, neither Festool (without a mod) nor the TSO are perfect and neither can be considered as clearly better/worse.

The Makitas are the only ones which are IMHO the ones to get in any case *in addition* to either a TSO or Festool set:
- they are the cheapest
- they are the only non-self-aligning, allowing for maximum/absolute accuracy, irrespective of the quality of the rails used
- they are the strongest, being suitable for semi-permanently joining of rails

Were I to go from scratch, two equivalent options come to mind:

A)
Get the Makita connectors set first. Then get the FS/2 set which includes the adjustable FS-WA square as well as the connector set and some other accessories for a very competitive price. That would give me one "optimal" set and one spare makita connector.

B) If I did not want the FS-WA (which is a must-have, in my view, but YMMV).
Get the Makita connectors set first. Then couple it with a TSO set, ideally re-thread the Makita for bigger worm screws to use the same HEX drivers as TSO and use one TSO for alignment and one Makita for strength in a set. That would give me 2 complete self-aligning connector sets with no waste.

Both scenarios allow/maintain the pure non-self-aligning Makita option for absolute accuracy which should be the baseline to have. IMO.

Hope helps.

 

[smorgasbord]

Thanks for bringing up Betterly - I hadn't heard of them before and looks like pretty impressive results:



And how to align with a straight edge:

 

[Peter Kelly]

No perfect system for joining guide rails but the Mafell / Bosch system is far and away better than the Festool model.

 

[mino]

No perfect system for joining guide rails but the Mafell / Bosch system is far and away better than the Festool model.

Their Aerofix system is brilliant.

But as for universally superior I would be careful there.

Their connectors are faster/more convenient while equivalent to the Festool self-aligning setup in accuracy. However there is no non-self-aligning option for absolute accuracy (with a straight edge/reference).

Another limitation of the Maffel system is the limited attachment of accesories and the fact the rails are narrower and lighter, thus less stiff for long rips. What makes them more convenient (lighter) also makes them less universal as some stiffness is lost.

For carpentry and shorter cuts, Maffel is lighter/more convenient and their self-aligning connectors are great for speed.

For flexibility, accessories and super-precise cuts with joined rails the Festool rails are superior though. They are laterally stiffer, able to connect with absolute precision when required (using Makita connectors) and with an unmatched accessories options portfolio.

 

[Cheese]

Besides the brilliance of the Mafell connector, I also appreciate that the Mafell rail has 2 clamping slots, one of which is only 24 mm from the anti-splinter strip while the single clamping slot on the Festool rail is 133 mm away.

[attachimg=1]

 

[mino]

Besides the brilliance of the Mafell connector, I also appreciate that the Mafell rail has 2 clamping slots, one of which is only 24 mm from the anti-splinter strip while the single clamping slot on the Festool rail is 133 mm away.

Agree, that is a big advantage.
Maffel designed the low-profile special clamps to enable that setup even.

All adds up to a lighter & generally more convenient system along with the Aerofix.

I see the Maffel system as more optimised for tasks which it can do at the cost of flexibility/universality. A purely "pro" geared setup while the FS/2 uses a more universal setup.

------
OT:
What I would like to see is a an "FS/2 HD" reinforced rail (15-20 mm raised hollow profile instead of 5 mm raised for the plate plate) option for cutting uneven material that would still be compatible with the standard FS system on the tool and accessories side .. one can dream what an HK 85 on such a rail could do.
[smile]

 

[Michael Kellough]

Ripping 2x6 construction grade lumber (Doug Fir) and straightening the resulting strips is the forte of the Mafell track thanks to that channel near the splinter guard. I did a bunch of that recently and using this inexpensive FOXBC Universal blade it was not as onerous as expected.

The blade matches the splinter guard exactly and the leaves a very smooth surface.

The Mafell dust bag can hold 16 feet worth of dust (at 1-1/2” depth) before it needs to be emptied.

 

[justin_248]

The strong points vis-a-vis TSO:
- only one connector is self-aligning, this means a potential for better accuracy
- the self-aligning connector is "stressing" the rail in a way where it is the strongest, allowing for connection that is a bit more stable than the TSO one

The weak points vis-a-vis TSO:
- the non-self-aligning second connnector is still the rail-denting type, limiting how much it can be tightened and thus counter-acting on one of the strong points above

Mino,
Unfortunately, I believe your information is dated regarding the TSO GRC-12.  TSO now ships two identical, self-aligning connectors with the kit.  I recognize in the past they did not, as you can see in their demo video, but this has changed.

I found the most important thing when connecting the rails is to ensure there is a gap of a little less than 1 mm between the two rails.  I just went and connected my rails four separate times across two uneven surfaces using the TSO connectors.  Using my precision straight-edge, I found the rails lined up perfectly the three times I had a gap.  However, the one time I did not have a gap, the rails were very, very slightly misaligned.  Sedge also suggests having a gap between the rails:=shared&t=97

 

[mino]

Mino,
Unfortunately, I believe your information is dated regarding the TSO GRC-12.  TSO now ships two identical, self-aligning connectors with the kit.  I recognize in the past they did not, as you can see in their demo video, but this has changed.
...

I have updated the text as was possibly not clear.

TSO always shipped two same connectors, as far as I was aware. And that is a disadvantage as the rails are not all identical in width. Thus having two connectors *attempting* to align introduces inevitable skew as well as unpredictability on top of it. Very small, but it is there. Festool uses only one aligning element and hence is (in general) superior on accuracy and mainly on repeatability as there are no two aligning mechanisms "fighting" each other.

 

[hamsey]

Definitely not aluminum. Too soft bends. Ask me how I know

 

[justin_248]

I have updated the text as was possibly not clear.

TSO always shipped two same connectors, as far as I was aware. And that is a disadvantage as the rails are not all identical in width. Thus having two connectors *attempting* to align introduces inevitable skew as well as unpredictability on top of it. Very small, but it is there. Festool uses only one aligning element and hence is (in general) superior on accuracy and mainly on repeatability as there are no two aligning mechanisms "fighting" each other.

Understood, I didn't realize they always shipped two identical connectors.  I haven't experienced this problem you're describing.  It seems to me that if the rails aren't a close enough match for the two TSO connectors, you probably have bigger problems on your hands which will affect your ability to use other accessories, such as parallel guides.  This is probably only a problem for people who are using two different brands of guide rails together.

 

[mino]

Understood, I didn't realize they always shipped two identical connectors.  I haven't experienced this problem you're describing.  It seems to me that if the rails aren't a close enough match for the two TSO connectors, you probably have bigger problems on your hands which will affect your ability to use other accessories, such as parallel guides.  This is probably only a problem for people who are using two different brands of guide rails together.

It is not a problem. I never said so. Just a difference between it and the new Festool connectors set.

The benefit of it is both connectors can be the same, simplifying operation. Is not a better/worse scenario. Different.

I wrote "very small" for a reason. The main limitation of (any) self-aligning system is it depends on a short part of the rail for accuracy. Any deviation/bend on that short part will be multiplied along the length of the rail. That is why I advise to have at least one Makita set for cases where long rips and/or absolute accuracy are needed. Even if one uses it rarely.
Comparing to that issue, the rails not being exact same, a challenge for the TSO setup, are an insignificant concern. But saying it does not exist would be false.

The question was about Festool versus TSO, and this is one of the main differences of otherwise very comparable setups. Hence was mentioned.
The biggest limitation of the TSO setup (as sold) is it does not have a "strong binding" connector in the set that can be tightened to the max. Which is incidentally the same problem Festool has ..
[smile]

 

[Neil Lickfold]

I recently made some Aluminium self aligning connectors from some 1/4 inch thick 7075 Al stock. I set up my bandsaw and a guide to make the strips to suite the Track rails width. For the inner rail, they ended up being 12.25mm wide.
I drilled a 5.5mm hole through at each end of the expansion slot. 40mm centres for the drilled holes. A 0.8mm slitting saw cuts a slot after the central hole has been tapM4 and the top csunk to 8mm diameter. After the slitting saw, I went in with a 3mm slot drill , through from the 5.5mm hole to the edge of the 8mm c'sunk section. Then milled through at the depth of the start of the tapped M4 with the 3mm slot drill. This relieves the sides of the Csunk feature to make it easier for the centre sections to expand. The rails have about 0.1mm width clearance on the central slot. So does not take much torque to lock it in tight.
The rails are a similar length to the Makita ones at 284mm long. The length of the bars they were cut from was already 284mm long and 3/4 inch wide.
The outer rail slot is a bit wider at 12.5mm wide and have made some for them as well.
The Makita rail joiners I got, I put in new holes at M5. The front 2 holes are 25mm from the centreline of the rail, and the back 2 are at 120mm from the centreline of the rail.
I managed to buy some flat pointed set screws M5X4mm long. They take a 2.5mm hex key or can be used with a Tox TP 10 key, like used for seating carbide inserts.
The self aligning connectors, I tapped them M4 for M4X6mm long CSK screws with the 2.5 hex hey. At 1.2N of torque from my insert screw driver TP10 , is plenty tight enough to hold the connector in place. The 2 rails joined nicely together and were as straight as my straight edge for a comparison. I don't have any alignment checking gear like in the video of the rail alignment tool.
My initial test has been done with a modified Makita set in the front slot, and my own self aligning connector in the inner connector slot.
For fine adjustments on the bandsaw , making the rails, I use a DTI and mag base, and move the fence the amount needed, and look at the dti as it is tightened. With the blade tracking correctly, it will cut fairly straight and parallel with a nicely welded blade. A touch up on the linisher and a corner edge break.
In the weekend will test the Ali outer self aligning bars, and see how they perform, or if they hinder the straightness of the assembly.
The small gap in the rails will be a must, as the rails are not accurately milled square on the end faces. I placed a piece of plastic from a drink bottle between the 2 pieces when joining and then remove. Its in the 0.4 to 0.3mm thickness depending on the section of the plastic bottle used.

 

[smorgasbord]

I'm a guide rail and connector newbie, but I think the approaches people have taken with miter bars is informative.

The original Festool and Makita connectors have the problem that they apply pressure vertically from a bar that fits horizontally loosely in the track. So, it's easy to cock the two rails and tighten down the connectors. The Betterly system was designed to hold the rails in alignment while you tighten the connectors. Most people it seems use a straightedge or level to align the rails and then tighten the connectors.

The newer Festool iteration of the connectors has two different connectors. The second is the same as the old. The first is a new connector that uses now-pretty-much-standard-for-miter-bar eccentric washers on one edge of the connector to force the straight side of the connector tight horizontally within its slot. Then you add the second connector for strength. Theoretically, this should do better at aligning the rails, at least if you're going through the trouble of using a separate edge/level to align them.

The homemade one by @Neil Lickfold above, though might have a flaw that I saw in early miter bar expansion attempts - centering the expansion slot. This pushes out both sides of the bar horizontally, so you lose having one edge of the bar being a reference straight edge. Somehow, relying on the expansion of each section being the same and affecting its position in the rail slot being the same doesn't seem certain.

The new Evolution bar connectors also have this problem I believe. So while they avoid the denting that was problematic over time (as did the Makita split solution), they don't enforce alignment. Take a look at most miter bars these days that have adjustments only on one side of the bars - I would think something along those lines would be best here as well.

EDIT: And apparently the Mafel/Bosch rail connectors work on the same one-edge-straight while the other edge has eccentric washer principle. And people report those as being good.

 

[Neil Lickfold]

With my rails as shown, Yes it is centrally expanding.
My thinking is that I would assess the alignment and see how the Saw or Router runs along the rail. As there is a 0.1mm difference in rail width are now looking to see what type of tape can be used to make both rails the same width. What ever tape is used on the outer rail or paint or coating, can be applied to the side of the joiner for the rail that requires re alignment.
My current thinking is to leave it like it is, and then apply a coating to the reference side of the skinny one, and then live with the 0.05mm miss alignment on the floating side.
The Festool connectors, favour one side when tightened due to the offset design of the relief slot for the flexure.