squall_line said:
[member=61254]mino[/member] or one of our other European brethren have one of the FS-WA angle unit and have stated that it is many lightyears beyond the original protractor head in terms of accuracy and reliability.
Correct.
The biggest advantage is the FS-WA
CAN be calibrated, this means one can "calibrate-out" even any tiny bend a rail can have /most do/.
The biggest disadvantage is the FS-WA
MUST be calibrated for accuracy:
- every time one changes the angle
- recommended also when changing rails (to calibrate-out any rail irregularity)
The detents are - by definition - only aproximate. So it is normal they do not give precise angles. Actually it is even desirable in my vie - > avoids the false impression a detent (of any kind) can be used for accuracy.
In other words, the FS-WA *allows* for effectively absolute accuracy, by the nature of allowing calibration against a precise engineer's square. The price to pay for this is one must calibrate against a known-good reference.
On the other hand the FS-WA/90 (aka GRS 16) does NOT allow for absolute accuracy as it heavily depends on the rail being absolutely straight for the overall angle accuracy. The advantage though is that one can get "good-enough" accuracy with it most of the time (as in with most rails).
Practical advice:
The simplest (as in cheapest) way to calibrate the FS-WA for 90° cuts is using the 5-cut method and tuning the until you get absolute precision. Then store the board (make sure it is at least 2'x2') and use it for future quick calibration.
Ideal material for this is the cheapest one - laminated particle board. It does not change shape with humidity or temperature.
The better way is naturally havin a DIN Class 0 (or at least Class 1) engineer's square of sufficient size. From what I gather this is a bit problematic in the US as there are the $300 Starret pieces and then all the junk for $20 at Amazon which is not worth $5 in reality ... In Europe this is easy as DIN is a thing and there are multiple makers in the $50 category for DIN Class 0 stuff. KINEX being my favourite as it is a local brand in SK/CZ ...
I got two FS-WA/90 at launch and lately one FS-WA ... having the FS-WA, I reduced my GRS 16(FS-WA/90) use to a minimum. Now use it mostly in pairs (both sides of cut) when need to cut very narrow stock or some aluminum profiles etc.