Hold Down

Design of structural and load bearing framework.
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servant74
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Hold Down

Postby servant74 » Thu Dec 09, 2010 6:25 pm


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Awesomeness
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Re: Hold Down

Postby Awesomeness » Thu Dec 09, 2010 7:07 pm

There is usually a perimeter of "wasted space" around the table, outside the routable area. One of my ideas was to install t-tracks in this are. It gains back use of the wasted area for something important, but at no cost to the design (just the cost of the t-tracks themselves). What do you guys think about that?

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servant74
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Re: Hold Down

Postby servant74 » Thu Dec 09, 2010 7:23 pm

Good idea. It needs to still be lower than a 'spoil board'. When re-surfacing a spoil board, and before putting another one on top, just don't want to have the t-track get in the way.

I have seen pictures of the edge of peoples spoil boards, where every time the get a new one, the just glue it on top of the previous one (never removing an old one). Then they use a surfacing bit, basically a flat bottom router bit that is pretty large, lie 1 to 2" diameter or more, to just quickly 'scrub' the surface of the spoil board, making it absolutely flat in relation to the router. Every time they do that, it takes about 20 to 50 thousandths off the current 'top' of the spoil board. Since the bit is so large, it can go half the radius off the edge of the routable area. So to that extent, be careful when positioning anything close to the edge of the routable area! :)

Does that make sense?

Another thing I saw was a 'quick xy zero' method. One guy went to extremes and had pneumatically controlled boards that would pop up from the edge area for the X and Y axis,
then he would slide his plywood or whatever to be routed to these boards, turn on his vacuum hold down, and have the pneumatic boards go back down into the table, so he has a perfectly aligned piece of wood ready to be routed. ... Neat technique, his implementation was pricey, but a great idea of a feature to optionally include.

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Awesomeness
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Re: Hold Down

Postby Awesomeness » Thu Dec 09, 2010 7:38 pm

But you don't have to worry, because you can't route outside the routable area. So as long as we keep it routable area plus 1", it should be ok. I think there are 2-3" of wasted space on each side of my threaded rod machine.

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servant74
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Re: Hold Down

Postby servant74 » Fri Dec 10, 2010 7:01 am

Good. ... I am sure all will become clear as we start seeing sketches or alpha versions of plans!

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airnocker
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Re: Hold Down

Postby airnocker » Wed Dec 15, 2010 10:55 pm

One of simplest, most versatile and elegant hold down methods I found was using pinch blocks and spoon shelf supports. Cheap and very effective. 95% of all the things I've cut, especially 3/4" plywood, I used slide, pinch blocks made from scraps of Pergo laminate flooring. My second method is simply a few wood screws, or more Pergo laminate flooring scraps and a few wood screws.

I lean toward low profile hold-down methods so there is no worry about accidentally running into something standing higher that the work piece.

When talk of hold-downs include vacuum tables, and T-tracks creep into the conversation, the concept of low-cost flies out the window, doesn't it?
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Awesomeness
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Re: Hold Down

Postby Awesomeness » Sun Dec 19, 2010 5:48 am


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Keith
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Re: Hold Down

Postby Keith » Mon Dec 20, 2010 6:22 pm

T-track is costly however anyone have a link to that chinese machine which looks soooo much like Patricks machine? They used staggered pieces of MDF to achieve a T-Track system. We could too!


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