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Thread: Is it ever OK to put screws in your bleeder board?

  1. #11
    Join Date
    Nov 2012
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    Default Lacquer

    Blackhawk

    We have a two pack lacquer we use in the spray shop. I mix that really thin and apply that with a brush. Soaks in really well, it dried quick too.


    Don

    The Tee track looks interesting.

    I can see a 'shadow mark' of a cut-out in the baseboard. How much below the surface is the track? Or did you take the track out when you were cutting those?

    Those oak cramping pieces - do you have those in different lengths?

    That piece of softwood down the X axis is the edge of that the X Zero or is that something to do with those beech blocks? Now that I'm thinking of the X Axis, how do you know the work piece with the pockets is parallel to the axis - are you measuring that, or do you have some sort of spacer from those beech blocks?

    It is really interesting, I've often thought that if I put one of these in my garage, that I wouldn't be able have a noisy vacuum and would need something different.

    Thanks for the picture

    Yours sincerely and in good faith
    Martin

  2. #12
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    Dec 2008
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    Default

    Quote Originally Posted by Martin Reid View Post
    Blackhawk

    We have a two pack lacquer we use in the spray shop. I mix that really thin and apply that with a brush. Soaks in really well, it dried quick too.


    Don

    The Tee track looks interesting.

    I can see a 'shadow mark' of a cut-out in the baseboard. How much below the surface is the track? Or did you take the track out when you were cutting those?
    ----> The tracks are about 1/8" below the surface of the MDO. My normal cut thru depth is 1/32". Yes, you will have cut out tracks all over your MDO board. But your spoilboard has no cut tracks in it.

    Those oak cramping pieces - do you have those in different lengths?
    -----> You can make the oak clamping pieces any size you want. They use a standard T-bolt with a knob. Very simple. And they can easily be modeled in VCarve or Aspire and made on the CNC.

    That piece of softwood down the X axis is the edge of that the X Zero or is that something to do with those beech blocks? Now that I'm thinking of the X Axis, how do you know the work piece with the pockets is parallel to the axis - are you measuring that, or do you have some sort of spacer from those beech blocks?
    ----> The blocks along the edge of the table are used as reference blocks for anything I put on the CNC table. Those reference blocks are mainly for plywood when making cabinet parts, but they work well for zeroing the MDO board to the X axis too. They are EXACTLY in line with the X axis of the machine. When I cut the tracks slots in the MDO, I used those reference blocks to ensure that the track slots are EXACTLY parallel to the X axis. When putting a piece of material on the MDO hold down board, reference the edge of the material with any of the tracks and you can be assured that the material is parallel to the X axis. I use a tape measure to set the edge of the material an exact distance from any of the tracks.

    It is really interesting, I've often thought that if I put one of these in my garage, that I wouldn't be able have a noisy vacuum and would need something different.

    Thanks for the picture

    Yours sincerely and in good faith
    Martin
    Martin,

    Let me try and answer the questions one at a time. They are inline in blue above.
    Don
    Diamond Lake Custom Woodworks, LLC
    www.dlwoodworks.com
    ***********************************
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  3. #13
    Join Date
    Jun 2004
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    Springfield Mo
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    844

    Default holes in vac table plenum

    I laid out a grid of 17/ 64 holes on 5-1/2 centers through the “high spots” in the vacuum plenum. The hole goes all the way through Trupan top and out of the bottom of the 3/4” plywood base.

    At the bottom of the hole is a 1/4 inch threaded T- nut which can be used to secure the hold down clamps.

    Sometimes I will use a lag screw coming up from the bottom to hold the work-piece using “pull down.” ... you have to miss the lag screws however...

    Works great, I cover the bottom holes with heavy tape when not in use, vacuum still works fine.
    Attached Images Attached Images
    The decimal point seems to be the most important on the z axis... x & y not so much....
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  4. #14
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    Apr 2007
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    Default

    I don't think enough can be said about adequate hold down. Along with destruction of material, edge quality and accuracy all are VERY dependent on good hold down. Most users don't experiment enough with alternate methods once they find one or two that work. I like curtiss' bolt method. When you can use them, you can really rock. Look at 4:15 into this video and see the force you can withstand with a few well placed bolts:

    https://youtu.be/fjk9FjHg4vg
    Gary Campbell
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  5. #15
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    The art of hold down is a lot like making concrete forms. You can go way overboard and nothing bad happens except for wasting a lot of time to set it up and trouble in taking it apart. You can go minimalist and end up with a huge pile of worthless mess. The art is finding the exact balance between excessive and minimalist.
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  6. #16
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    Lots of good information about hold downs. A few years ago there were fellows using the Raptor gun which shoots plastic nails to solve this problem.
    https://raptornails.com/product-catalog/nailers.php

  7. #17
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    >> A few years ago there were fellows using the Raptor gun which shoots plastic nails to solve this problem.

    I tried going that route but it was essentially a waste of time. They would help in maybe 5% of the situations. Usually, they didn't hold well enough or they wouldn't penetrate the material.

    There is no magic bullet for hold down. Having a variety of strategies, a large collection of clamps and long pieces of scrap wood work best for me. The primary thing one must know is what forces are involved. That's the key to success with hold down. If you don't know how much force the machine and bit are going to impart to the work, the most efficient solution can't be applied. Getting familiar with this aspect of using the CNC is probably the best road to success.
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  8. #18
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    I'm in full agreement with John. There's not a single answer to these questions. Below are some of the hold downs we used. I copied the design from piano keys. I liked the look and they worked out well.

    Attached Images Attached Images
    Last edited by joe; 06-22-2018 at 12:11 PM.

  9. #19
    Join Date
    Dec 2019
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    68

    Default

    I know this is a very old thread, but is "bleeder board" the same as a "spoil board"

  10. #20
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    Default

    Yes. It's purpose to provide a flat, true surface to mount material on. You can screw it down, but it is recommended to use caulk to attached it to your vacuum plenum. Putting screws (or any type of metal hardware) in could destroy bits in a split second if you touch them while running your machine.
    Don
    Diamond Lake Custom Woodworks, LLC
    www.dlwoodworks.com
    ***********************************
    Life is not a journey to the grave with the intention of arriving safely in one pretty and well preserved piece; But to skid in broadside, thoroughly used up, worn out, bank accounts empty, credit cards maxed out, defiantly shouting "Geronimo"!

    If you make something idiot proof, all they do is create a better idiot.

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