Positioning material

[woodworx]

What are some of the methods you all use for positioning your smaller pieces that are being cut? When I have to be precise and when my vacuum won't hold I pocket a piece of mdf, or particle board and set the piece down in pocket. I see that some people use t-tracks and others just screw their piece down to the bed. How are you getting accurate cuts? With a tape measure?

[beacon14]

I cut a long narrow strip of 1/4" scrap material into an "L" shape, with each leg 2" wide. I place the "L" shaped piece up against my stops (I have stops bolted to the edge of the table). I place the workpiece in the crook of the "L" shape, and place more scraps of 1/4" material all around it to lock the workpiece into place and to cover up the rest of the zone. I then create the toolpath with the workpiece bottom left corner at 2,2.

Here's a couple of pics of a variation of this technique. These pieces were 2 1/2" x 3 1/2".


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[myxpykalix]

I have a jig with a 90 degree corner that corresponds to the corner of the table and i just screw down scraps of mdf to hold the part into the corner.

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[chiloquinruss]

Good responses, thanks Justin for asking, I wanted to know also! Additional question for the posters, is the hold down strictly mechanical or do you also have some vacuum running through the jig? Is the piece you use for the jig removable for other uses or is it a one time only piece? Thanks in advance! Russ

[Gary Campbell]

I use air operated "fences" and pins that slide in to the Y zero or pop up for the X zero.

We use them to locate parts on both the Y = 0 and Y = 49 positions on the table. That allows us to accurately locate and process both end panels of a cabinet at one time. (or any other 2 parts)

We use a custom zero routine that electronically locates the fences and pins and insures that they are square. Sorry, no pics at this time.
Gary

[beacon14]

In my case including the pics above there is only vacuum holding the workpiece down; the vacuum also holds the 1/4" masking down which locks the workpiece in place. In order for the workpiece to shift the masking would have to shift also. Can't tell from the pic but the masking has a non-porous face on the side facing the table, it's not just 1/4" MDF.

[chiloquinruss]

'Can't tell from the pic but the masking has a non-porous face on the side facing the table, it's not just 1/4" MDF' - thanks for the clarification. Russ

[cmagro]

For smaller parts I create a "groove" and a "base". For what I do it works out very well as I am able to keep the "base" or make multiple ones for a lot of parts.

Here is a sample...

First I make a base for the part to shape and include "wings" for securing it down.

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Then I make a groove...usually using some scrap around the shop and locating it anywhere on the bot. The "x" and "y" location can be anywhere within the scrap and from this point will be maintained for the rest of the part.

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I use the "base" and draw an outline on the wood blank and cut around the outline leaving 1/8" or so. Then I secure the base to the wood blank..in my case I use a couple of trim screws.
The base along with the blank pops right into the groove and gets secured down at the wings. Everything is super tight.

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Shape the part..which has already been aligned by creating the groove.

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I usually keep the base for future use...when needed I just throw a scrap piece of osb or something on the bot..cut the groove...slab the wood blank that is secured to the base in the groove and run it.

Most of my smaller stuff is done this way. I do not use a vac hold down for anything.

Christian

[woodworx]

Christian, I have found this method to be the best. Building jigs that come in pieces can be time consuming. Say if I am doing a carving in a door and the door is 15X20, all I have to do is put a piece of scrap sheet I have lying around and lay it on the table. I can screw or use the vacuum to hold this piece down. I take my 15x20 shape and cut an inside profile on the scrap board all the way through with an allowance of -.05". That way the door fits snug down in the pocket. Usually a small shim will get that bugger in there really tight. Now I know my piece will be accurately coordinated.

[cmagro]

There you go Justin....what I like most is by cutting the inside profile you are perfectly aligning the door at the same time. When I first used this method I did not make an allowance and the base (or part to cut) was a little too snug. Climbing on the bot and jumping up and down on the part to make it fit was maybe not such a good idea.

[myxpykalix]

Justin,
What you may not see with mine is that i have take the mdf over to the tablesaw and cut a small dado in it so that when i screw the mdf down a lip is hanging over the edge of the material keeping it from raising up.