Thanks everyone.
It very much looks like 3M d/s tape is the "safe choice" or whatever. I'll do the RS components thing, probably (or Rapid).
You do need to be able to get the stuff off again nicely, really, so just being sticky isn't the whole story. It took well over an hour yesterday to get all the residue off (thumbs rolling it off having loosened it with a heat gun, then cleanup with Meths). The new strip had d/s tape already applied, so I've fitted that one and kept the old one for next time.
Two gotchas I found (in case anyone's interested), one of which is really annoying:
#1 the new "official" strip is different thickness to the old one. THIS IS INFURIATING - THANKS MAKITA!
Why? basically because it screws up the geometry good & proper:
1: The saw cannot be properly perpendicular on both thicknesses of strip - right for one or the other, but not both together. It's a simple matter of wedge angles. So one of the two thicknesses means it won't cut square when it says it should.
2: The depth gauge will be off (again!). It's a major flaw that this saw only has a depth setting for running the saw directly on the stock (i.e. not on the rail for which it was designed!), Now I have to regard everything about the depth setting as pure fiction. It's no longer a matter of adding a specific offset - you have to guess the thickness of the rubber strip, too. The saw was not cheap; this is not acceptable - BUY Festool instead! (You can tell I'm seriously cross about this!).
3: Back at geometry, changing the thickness of the splinter strip also upsets the positioning of bevel cuts. Not only will the angle be off (which matters if you're doing mitres or whatever), but the position of the cut will be wrong, too.
4: I now know why my rails won't join together properly without a bump at the joint.
I can't emphasize enough how ridiculous and poorly done this is: ISO 9000? Pah! Back to school you BRITISH cheapskates. ! bought your kit in part because of where it was made, and I can't afford to replace it really. I now discover a lot of its value - the precision and ability to make good long straight cuts - is what the Victorians called "sales puff".
#2: On the practical problem of fitting the new strip: With the backing paper still on, it's very slippery. I clipped it carefully to one end of the 3m rail, and unrolled it adding clips as I went. At the other end it was about 60mm over - that's good, as the sticky will have aged a bit at the extreme ends whilst in stock at the supplier.
So I started with the overlength end, pulled it back a bit to allow trimmable overlap at both ends, and worked back along, remioving clips as I got near to them. Except the splinter strip ran out before the othere end!. When I got to within a few inches, I removed the last clip hiding the end of the rail, only to find the strip had slid down under it, leaving me with a 20mm gap (no rubber).
Much cursing, rapid conscription of my wife, and removal of strip "quick, before it gets completely stuck on there!". She's a saint! Between us we shifted it along enough to get it neat at both ends, and not too stretched (or it would pull loose over time).
Two points from that: I should have double checked (but my clamp was pretty tight!), and Makita could have allowed more at each end - there's actually only about 30mm altogether. It looked really close to start with, which is why I originally only allowed a small overlap at the end that moved.
And the final ignominy is that I've confirmed what I've always suspected:
My 3m Makita rail is concave by about 1.5-2mm in the centre (I think). It's been looked-after and it's been like that from new.
Assuming the 19mm MRMDF sheet I'm hoping (sometime next year, at this rate) to trim is straight, then a simple test against the sheet edge shows it's impossible to align it parallel to the edge (after trimming the splinter strip, with a brand new blade, too).
Why do you buy a Makita 3m rail in the first place? Evidently because you're a mug, like me.
It will be handy in smaller pieces, I expect. I'll start saving for a Festool one and be grateful the saw runs on both brands.
E (the grump).
PS: I had a birthday yesterday. I'm not saying how old I am, but one of my earliest memories of being out with my dad was going to Radiospares somewhere in North West London (I think) and being lifted up to sit on the counter while he placed his order. I think I was four at the time, or thereabouts. And yes, it was well over fifty years ago. I know they're not cheap, but they're still there and their stuff is still good quality...
