Hi Alf,
Observations of my LN 140.
As the LN web site says, the skew angle of mine is 18 deg.
Also from the site (which is also in the product sheet incl. w/ the tool):
Blade Adjustment: Hold the tool in one hand with your fingers supporting the sole of your thumb on the cap iron just in front of the screw. Loosen the spinwheel, and with your thumb still holding the blade and cap, adjust the blade. Tighten the spinwheel. Do not overtighten (you should be able to adjust the blade after loosening the spinwheel about 1/4 turn).
Because of the unsupported right side, there is some flex inherent in that thin metal edge when the cap is tensioned on the blade.
This will produce a slightly tapered shaving which will normally not present a problem, but if on occasion it does, adjust the blade slightly out of parallel with the sole to produce a shaving of uniform (not tapered) thickness.
I seperated the paragraph and added the bold for ease of reading.
The tension on the blade is truly important. It will distort the bed if it is too tight. It needs to be just snug enough to keep the cap from falling off. Well, a little tighter than that, but not much.
With that said, however, I measured mine. The mouth/blade is in as near a perfect relationship as these old eyes can measure. The blade projection is even across the sole and at the same angle as the mouth using the protractor head on my old Tumico combination square. It takes an even shaving thickness--at least even enough according to two different dial calipers.
The mouth/blade gap is between .5 and 1mm. I didn't care to measure exactly.
However, imho, a skew block plane such as the 140 does not need a tight mouth. The shavings one sees in Derek's Wood Central post from cross grain cutting are obtainable from a chisel--I pare tenons often with a chisel. You probably have as well. So the mouth/blade gap is mostly a non-issue and certainly not something to get too worked up over.
In fact, it *only* gets more important as one closes the mouth in a tighter relationship to the blade edge. What is important is to produce even shaving thickness. Or uses the 140 for long grain cutting--which I also do quite often, and it cuts just fine with moderate hardwoods (like cherry) to less than friendly hardwoods (like say bubinga or cocobolo).
Do also realize that as you adjust the blade projection, that the blade can and does often twist (even slightly). This is an inherent design flaw that I wish LN would have addressed more than simply lowering the blade bed angle.
I do gring the blade geometry to match the mouth--and btw, skews are one blade type that I do use jigs for consistently. Once the blade is back on the plane, the cap adjusted to hold the blade so adjustment is still easy, I slide the blade so that the right edge is against the removable fence. That puts me either where I do not need to adjust it or where I need to only move the back of the blade a little. It will pivot against the cap iron screw.
I either sight down the sole to see the blade projection or use my finger tips and feel the projection. This is a plane that demonstrates how important it is when adjusting blade projection to always back off and tighten the adjusting nut to bring the blade forward. If it ends up too deep, back off and come forward again. With the spinwheel as loose as it should be the backlash has to be accounted for.
Why don't you send LN an email with your concerns. They'll address them.
, I can't decide whether I should be asking for a replacement or not... What d'you think? Or does this effect a lot of L-N #140's so I should stop worrying anyway?
