It doesn't make any sense- WTF???

[arachnid]

Hi guys.

Something weird..... I want to have a total stack of 7mm. When I measure each lam on it's own and sum them up- it's 7mm. But, when I stack all the lams and physically measure with a cliper- I get 8.5mm...

What am I doing wrong?

[EvilDogBeast]

When they are all stacked together is it clamped together tightly?  Also, are the calipers and all the lams clean and free of dust and chips?  A little dust between each lam or the jaws of the calipers can add up quick.

[skeaterbait]

I have now canceled my Psyche eval. I thought I was the only one that encountered this sort of thing.

[arachnid]

I held the lams and squized them in my hand so what you say makes sense.
Thanks

[kennym]

I'm with Chris, the calipers only check a small section, the lams together have more surface pressed together with the roughed up sanded surface. You would have to clamp pretty hard to get it all laid down if ever.....

[Roy from Pa]

I have now canceled my Psyche eval. I thought I was the only one that encountered this sort of thing.  

Lonnie, maybe ya better reschedule it..    

[skeaterbait]

Originally posted by kennym:
I'm with Chris, the calipers only check a small section, the lams together have more surface pressed together with the roughed up sanded surface. You would have to clamp pretty hard to get it all laid down if ever.....

But if you are using the flats of the caliper jaws, they are going to lay on top of the sanding ridges, which should give the same measurement as gets measured with them all together... ???

[Robertfishes]

I measure each piece and add them together  for total stack. For me I find its best to measure the same way each time, that way my log book entries are consistent. I have never measured the stack as one unit. I check my calipers with a known standard that came with my Mitutoyo dial caliper and a good set of Feeler gauges.

[kennym]

Originally posted by skeaterbait:
 

Originally posted by kennym:
I'm with Chris, the calipers only check a small section, the lams together have more surface pressed together with the roughed up sanded surface. You would have to clamp pretty hard to get it all laid down if ever.....

But if you are using the flats of the caliper jaws, they are going to lay on top of the sanding ridges, which should give the same measurement as gets measured with them all together... ??? [/b]

But you are pressing 2 surfaces instead of 8

Take two or three rough sanded lams...  Measure them individually and then measure in a stack... The stack will usually always be greater... 1.5mm difference sounds like a lot though...  How many are you stacking??
  Do what Robert says...  Do one way and stay Consistent or measure both ways every time just to have extra info to fall back on but only use one method to determine draw weight...

[arachnid]

On this bow I have 3 cores + 2 glass. I always check the individual lams and add them up. This time I just wanted to make sure I got the stack right and BAM.... the caliper showed it`s a lot more them I calculated. That`s why I posted this question here.... can`t be too sure...

[EvilDogBeast]

If they all measure correctly as individuals, I would chalk it up to sawdust and chips in the joints right now.  If you really want to make sure I would wipe them all down thoroughly and then clamp them together.  It should then be pretty damn close.

Open up your caliper to drain out and have your  pinion grease inspected plus you might have a sprocket with some missing teeth in there... You also might need a lam condenser...  I got an old one in good shape that I could sell you...  Cheap...

[kennym]

May have been what happened last winter when I had one come in 20 heavy ... lol

[arachnid]

Originally posted by Shredd:
Open up your caliper to drain out and have your  pinion grease inspected plus you might have a sprocket with some missing teeth in there... You also might need a lam condenser...  I got an old one in good shape that I could sell you...  Cheap...

What's a lam condenser?

[Robertfishes]

Arachnid, I bought some elbow grease from Shredd, didn't work that well..he is pulling your leg...

Lam condenser???  I am joking with you...  

[OkKeith]

You get Lam Condensers right next to the Muffler Bearings and the Bumper Fluid.

OkKeith

[Woodpuppy]

Muffler bearings.... reminds me of working in the bicycle shop 20 years ago. We’d prank our buddies by pulling their inner tube valve stem cores and putting a few bearings inside the tube, then reinstalling the cores and airing their tires back up. Best done before a long ride

[arachnid]

Originally posted by Shredd:
Lam condenser???  I am joking with you...    

Oh.... sorry....