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Main Boards => The Bowyer's Bench => Topic started by: skeaterbait on January 30, 2010, 10:51:00 PM

Title: LAM grinders unite
Post by: skeaterbait on January 30, 2010, 10:51:00 PM
A quick question for you experienced grinders/builders.

I am tinkering with my first real lams tonight and I built a sled to run the lams through the drum sander. I made the sled out of 1/2" MDF figuring it would be pretty consistant. Probably the first mistake.

What I am finding is that my lams are coming out pretty uniform over the bulk of the length but one end is winding up being about .001-.002" thicker than the opposite of a 36" peice.

Is this really going to make a big difference on the finished product?
Title: Re: LAM grinders unite
Post by: sw on January 30, 2010, 10:57:00 PM
in most cases .002 is going to be a 1# of difference. Not going to make building a bow or tillering the bow hard at all.

You can always cut the lams and put the same thicknesses at the tips to balance the bow but even commercial thickness sanders like i use will have a variance of .001 to .002 inches over a 72" run. Running .001/.002 over 36" is not bad at all.


Dave
Title: Re: LAM grinders unite
Post by: Randy Morin on January 31, 2010, 09:22:00 AM
Which end is turning out thin?  Most drum sanders will chew the leading end as it is fed into the drum a little lower as it bites in.  If its only the last 1-2 inches thats what it is.  

Other than that have you mic'ed your MDF?  It is usually dead nuts consistant and I think 1/2 inch thick is a good choice.  1/4 inch would work too.  You want a little flex so the sled can sit down on the flat feed table from the roller pressure.  Sounds like to me you are getting some nice lams already.
Title: Re: LAM grinders unite
Post by: skeaterbait on January 31, 2010, 02:41:00 PM
I didn't think it through enough to mic the MDF, seems kind of obivious now that you mention it. It is the leading end that's a touch thinner though.

A second question I thought of after the fact, once I get the lams where I want them and I sand an angle on the butt ends, is there any reson that I shouldn't glue those ends together prior to putting them on the form? Basicall making one long lam.

I have heard horror stories about trying to keep them together when getting them clamped up.
Title: Re: LAM grinders unite
Post by: kennym on January 31, 2010, 05:52:00 PM
Yep,make it a fairly long angle,I use loctite CA from walmart.

Here is how I grind em(on p2 I think)

http://tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=125;t=001165;p=1
Title: Re: LAM grinders unite
Post by: skeaterbait on January 31, 2010, 07:20:00 PM
Thanks Kenny. I thought I had seen it done and that may very well be where I saw it.

I am going to make a bow two without glass to get the hang of making lams and tillering a lam bow then I will be ordering some glass from you.

I was in hopes that you wouldn't be opposed to me picking them up. I am only a couple hours from you and that would make a great bike run some sunny afternoon. Not only that would be great to meet you and maybe bend your ear a bit.
Title: Re: LAM grinders unite
Post by: kennym on January 31, 2010, 09:43:00 PM
Lonnie,that would be cool!
Title: Re: LAM grinders unite
Post by: skeaterbait on February 01, 2010, 08:20:00 PM
Heck, ain't as bad as I thought, only hour and a half.