Darryl Keil Last Activity 2025-09-09 11:09 AM
4 replies, 2870 viewings
 
back
Navigate threads:
< Previous Thread :: Next Thread >
 
^ Top
mike mcnerney

Posts: 87

Joined: 2003-07-17
Location: ottawa ontario

User Profile 
Subject : vacuum clamping devices
Posted : 2008-10-07 5:22 PM
Post #34982
I have been wondering about this for a while & finally saw an example of one in th LMI guitar stuff catalog. They made a "sub table" to hold the workpiece. In this case a guitar fingerboard, to run through a molder to shape a curve down the length of it. This sub table holds the board with vaccum pressure. It has some kind of seal around the perimeter of the board. My question is this, what is the minimum height this seal has to go above the "sub table" to hold the board. My goal is to make such a table to hold stock & send through a thickness planer & be able to safely plane solid stock very thinly, hopefully as low as 1/16 to 3/32". I figure I need a helical cutter head too.
Mike McNerney, ottawa


 
^ Top
Don Stephan

Posts: 825

Joined: 2003-07-18
Location: Cincinnati, Ohio

User Profile 
Subject : RE: vacuum clamping devices
Posted : 2008-10-07 7:01 PM
Post #34983 - In reply to #34982
My age must be showing, because I'm confused as to the premise. Material 1/32" thick is going to be very flexible, and if the perimeter sealing strip extends above the sub-table even 1/32" it's going to flex the stock being planed, and on the last pass the stock between the sealing strips will bend down and be flat on the sub-table, the planer will remove the stock over the sealing strip, the vacuum will be broken, and the stock will get caught in the knives and be shattered, no?


 
^ Top
mike mcnerney

Posts: 87

Joined: 2003-07-17
Location: ottawa ontario

User Profile 
Subject : RE: vacuum clamping devices
Posted : 2008-10-08 6:58 AM
Post #34984 - In reply to #34983
Yes, of course you are correct, I am hoping that the seal might be as little as .005 above, and it might suck down right to the table too. I was hoping to find someone who had tried it. In the example I saw in the catalog, a typical fingerboard is approx 1/4" x 2 1/2" wide so maybe the vacuum does not deflect it?
mike mcnerney


 
^ Top
Darryl Keil

Posts: 1455

Joined: 2003-05-22
Location: Maine

User Profile 
Subject : RE: vacuum clamping devices
Posted : 2008-10-12 7:09 PM
Post #34992 - In reply to #34984
Mike,

Basically 1/64" would work. All you need is negative air space, doesnt matter how thin it is between the work piece and base as long as there is some air space.

Darryl Keil


 
^ Top
Brad

Posts: 87

Joined: 2008-04-22

User Profile 
Subject : RE: vacuum clamping devices
Posted : 2008-10-08 6:35 PM
Post #34985 - In reply to #34982
I am guessing since you mention guitars you are probably talking about some pretty nice stock. I am not sure I would send it through a thickness planer. I dont mind sending thin cherry stock through the planer, but I know occassionaly I will ruin a piece or two doing it this way. The helix head will help, but another part of the problem is the distance from the infeed/outfeed rollers to the cutterhead. Most use a wide belt or drum sander for this type of work. A wide belt with a platten is very well suited for this type of work since it holds the stock firmly. I take it Certainly Wood does not have any suitable thick veneer stock to your liking?

Here is a discussion from the woodweb for using a bed on a drum sander. No readon you couldnt try this on your planer, but be prepared for some damaged stock.

Q:
I had a local mill resaw some 13" x 8' boards into 1/8" thick veneers. the thickness varies enough that i need to thickness them on the drum sander before i can use them. im looking for suggestions or recommendations on making a sled to feed into the 24" woodmaster with the sanding head. any ideas?.

A1:
Just use a slab of MDF, and double-stick tape the leading edge of the veneer to the front of the sled. You might want to run the MDF through the sander by itself first, to ensure that its top surface is parallel to the drum.

A2:
i tried the MDF with the double stick tape placed in a 1/32" dado so that the veneer was flat on the sled. it worked fine for a while but since i had about 75 sqft to sand the tape was a bottle neck so i just placed the veneer rough face down on the sled and roughed up the sled with 36grit belt and the friction alone held the veneer in place.

Brad
back
Navigate threads:
< Previous Thread :: Next Thread >
Legend      Notification  
Administrator
Forum Moderator
Registered User
Unregistered User
 Toggle e-mail notification


Logo by MAZY
Running MegaBBS ASP Forum Software v1.5.14b public beta