Lam Tolerances

[PapaB]

What kind of thickness tolerances are set on parallel and tapered laminations?  What is the acceptable range?

[Sixby]

.002 across lam on total stack on my bows is max. The only way to get those tolerances is to flip the laminations as you grind them. I flip them over on each grind and mic each one in several places to establish how the machine is running. Perfect is just barely good enough. seriously.

God bless, Steve

[PapaB]

Sixby,
What exactly do you mean by this:
".002 across lam on total stack on my bows is max"?
Does that mean .002 per lam?

Thanks.

[Bradford]

What he means is that if you measure the thickness of your lam.. say at .080.. then all up and down the lam and left and right of the lam has to be the same.

So if I measure the left side of my lam stack.. if I am reading right.. say all three lams put together.. and it reads.. .210, then the right side better be no more than .212 or less than .208.

I agree with Sixby, I also flip my lams as I grind.  To easy for my grinder or sandpaper, to be a little off or different from left to right.

I don't think I am quite that exact when doing fiberglass.  I usually go for .005, and have not had any problems.  But in the quest for perfection, it is the correct way of doing it.

So for your first bow or two, just get it as close as possible and it will still work good for you.

[PapaB]

Thank you both for responding.  That really helps.