Pneumatic presses

[David Love]

I didn’t get any noticeable bend.  The beams I used are 2” x 3” and since my
shop is small and I can't have a designated area for them and have to move
them around for storage light was key.  I don’t use an upper caul, just a
lower one.  The upper doesn’t seem necessary.  I do keep the pieces that I
cut with the band saw from the ends of the ribs when I taper them and just
lay them over the thinner end sections before clamping to give an effective
uniform height of the rib all the way to the end.  I did have some leakage
problems on a couple of my valves.  Not sure what that was about.  They
weren’t terribly expensive (Ace Hardware specials) but I may look into a
more reliable gas valve.    

David Love
davidlovepianos at comcast.net
www.davidlovepianos.com 

-----Original Message-----
From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf
Of Farrell
Sent: Wednesday, February 27, 2008 7:01 AM
To: Pianotech List
Subject: Re: Pneumatic presses was RE: Emailing: P2130064

Looks really great David. How much bend do you get from the aluminum beams?
Gosh, those must be light! My 5' press gets pretty heavy.
 
Because I use a radiused upper caul, plus the difference among rib heights,
I find that I need to position the upper caul up or down several millimeters
for any given rib. In the picture below you can see my upper retaining pin
at the top of my angle iron. That is located in one fixed position. I simply
have an assortment of maple spacer blocks that I place between the retaining
pin and the top of the upper caul so that I get the hose shape I want (not
squished and hanging over the sides of the rib, and not so high that the
hose isn't in full contact with the rib). (Sorry the picture is kinda dark -
couldn't find another better one.)
 
'Course, I guess you'd "have" to make yours out of aluminum - or maybe
titanium!  Or not.
 
Terry Farrell