Lee Valley 62.5 LA Jack

Re: Lee Valley 62.5 LA Jack

Frank D. in Montreal

>Hi Greg,

Thanks for sharing your impressions. I'm a really big Lie-Nielsen fan, and I don't have the 62, but I won't buy yours because I like my LV 62.5 as much as you liked the one you tried out. I'm in the process of comparing the two planes for another Web site and I have pretty well come to all of the same conclusions you did. I think that plane is a winner. Their adj. mouth block plane was my first block plane, but now I only have LN block planes. A lot of people like their block plane and I still think it's worth the price but I don't think it's quite in the same league as the LN. JMHO. I don't know about that chamfering gizmo though. To each their own I guess but I find chamfering goes really well with a spokeshave (I have the LV high angle and like it a lot too).

I have a question about the 62.5. Rob Lee mentioned the other day that Veritas grinds the sole .015" concave, plus or minus .015", so as to make sure the sole isn't convex. I checked the sole on mine before I read his comment and found those measurements to be true; what I'm wondering is if a slight convexity wouldn't be better than a slight concavity, especially lengthwise? Doesn't a slight concavity in the sole make the plane take a slightly thicker shaving toward the beginning and the end of a cut? I used a very slightly convex #7 for over a year with no problems. Maybe Woodburn Bob can help me out here.

In any case I still like the plane a lot.

Frank

(who just reread and corrected his vexes and caves about four times...)

Small correction....

Rob Lee

>Hi Frank -

Just a small correction...the tolerances numbers are actually .0015" .... one and one-half thou, not fifteen thou.

We actually shoot for flat, to a maximum -.003" (three thou concave) over the entire length of the sole...

In the previous post - I was illustrating that this could be expressed as -.0015" +-.0015" for conceptual comparison only....The target is still 0.000" .

It's also important to understand that variation in a plane sole is primarily due to casting deflection while being ground. The deflection can occur with clamping (clamping the sidewalls of a casting "bows" it - and results in a concavity when released) and with deflection due to the load applied when grinding. As material tends to be concentrated around the mouth of a bench plane - it's more rigid, and there's typically not much error there.

Cheers -

Rob

Thanks Rob

Frank D. in Montreal

>Sorry 'bout that, wouldn't want to spread a misconception. Watching my cons and I forgot a "0"--pretty big difference, but I still get mixed up. Thanks for the explanation too.

Frank

Re: design, tolerances, and costs

paul womack

>It's also important to understand that variation in a plane sole is primarily due to casting deflection while being ground.

Hence the cost of accuracy. If more, lighter, passes where made in the grinding, deflection would be less, and tolerances tighter.

But the grinding would take longer, increasing the cost.

It's all about design and tolerance. Knowing what tolerance you need is a high design skill, and coming up with a tool design which achieves the same results with lower tolerances is a design engineer's ultimate goal. Over-specifiying tolerances is a design cop-out, although a very one useful in shop made one offs.

It's obvious that a "Holtey" (lapped in the engineering sense of the word) smoothing plane sole is flat enough. The difficult question (to which have never arrived at, nor heard, a convincing answer) is how flat does a smoother sole need to be.

BugBear

Re: design, tolerances, and costs

Brent

>Hi!

Bugbear asks "The difficult question ... is how flat does a smoother sole need to be."

Frank D. asks "I'm wondering is if a slight convexity wouldn't be better than a slight concavity".

Given the tolerance Lee Valley aims for, one might also ask how flexible the plane is. Pressing down on the knob and tote of a convex plane would tend to flatten the plane. How much pressure applied at the knob and tote is needed to cause the 62.5 to flex by 0.0015"?

With a concave plane, since pressure is applied at the ends, there would be no change in the shape of the plane. In fact, since the blade pressing into the wood must be resisted by the body, a convex plane would be more convex with use.

This problem arises particularly with wooden bodied planes - tightening the wedge can cause the plane sole to become convex lengthwise. It is then very difficult to get fine shavings.

Unfortunately, Frank D. real question got lost in a correction of tolerance.

So, what are the answers?

Should the sole be concave or convex?

and

What should the tolerance be given that the plane will flex with use?

Brent, in cloudy but dry Victoria, B.C.

Tolerances, cabbages, kings, etc.

Roger Nixon

>A pessimist sees a half empty glass.

An optimist sees a half full glass.

An engineer sees a need to tighten up the volume specs on glasses. :)

I agree with you, Brent, that a little convexity is better than concavity.

As to the plane flexing, Jeff Gorman did a nice experiment documented on his web site that shows it doesn't take much force at all to flex a Stanley plane.

As to how flat? As long as the mouth sits hard on the workpiece and most of the sole does as well, I can live with a few spots that don't touch. A small bump just in front of the mouth could cause problems even if it is only .0015" or so.