Fixture table building questions

[SRdesign]

I’ve found a few posts about fixture tables but I have a few questions for the folks here who have built their own. I have a 4x8x1/2” sheet of steel that I was thinking of building a 3’w x 6’L x 6”h fixture table out of. I have access to a mag drill and annular cutters and I don’t mind drilling all of the holes, it takes a long time but they are nice clean holes. I built a table at work and drilled all 197 holes 4” on center. My table and plasma cutter cut very nice and smooth with very little bevel but I’ve never cut 200ish 5/8” holes with it. It would be much easier on the front end to just hit a button and watch it cut, but I don’t want to ruin a whole sheet or have to clean up 200ish holes. Any advice from someone who has built one of these would be appreciated, or someone who cuts a lot of holes in thick plate. Thank you.

[weldguy]

I have never built one but have always wanted to. For me I would stick with drilling them, it will be a long arduous job but is the way to go for something like this. If you end up building one I would love to see it.

[TJS]

I just converted my welding bench to a "fixture table" this past weekend. As Weldguy stated, stick to drilling them with annular cutters and the mag drill. I will be using pretty precision 5/8" round bar for my clamp set up. I made a jig on my Bpt mill to get the 4" spacing. You can see my jig in this vid.

[SRdesign]

Thanks for the feedback/confirmation guys. That’s kinda what I was leaning towards but I figured I’d ask. Do you see any downside to making a jig like the one in this video? Fast forward to 8:15

[acourtjester]

I hve a solution for one of your concerns and that is hole placement. Why not draw up a pattern in your CAD and dimple plasma for center marks on the steel quick and easy.

[SRdesign]

I hve a solution for one of your concerns and that is hole placement. Why not draw up a pattern in your CAD and dimple plasma for center marks on the steel quick and easy.

I’ll be honest, I’m not familiar with doing a dimple plasma operation.
I was thinking of going about it two different ways.
#1 One way would be to make a jig like the one in the video I posted, once the jig is bolted in and clamped down you can easily insert your annular cutter in the holes and turn the magnet on to lock the mag drill down. Then start drilling.
#2 The other way I was thinking of doing it is to buy a sharpie holder from you and draw a grid with my plasma table. Then mag drill at every cross hair.

The con I see with #1 is building the jig and not having one detail right and screwing things up.

The only con I see with #2 is that I would have to make sure the sharpie stays perpendicular and lining up the pilot on the annular cutter this way can sometimes be annoying.
The more I think about it I might go with option #2. I can always double check my lines with a straight edge and even center punch all of my holes first.
I appreciate you guys that are always active on this forum to bounce ideas off of.

[acourtjester]

Your choice here is a video of me using to make drill holes on a project dimple were on separate parts of the nesting G-code. and the second is a PDF file explaining the setup.

[SRdesign]

Thank you for that

[adbuch]

This is some great stuff! I really like the idea of the pattern - either cnc plasma marked as Tom suggested, or perhaps using something like the Easyscriber to scribe the marks (I would use cross hairs instead of circles). The use of the moveable drill guide could be problematic due to the tolerance buildup as the drill guide is moved along the table. The cumulative error for hole location using this method may be a problem. Particularly if the table is also to be used for precision fixturing.

DAvid

[SRdesign]

One step closer. Made a sharpie holder completely based off of Tom’s (acourtjester) design. Still have a few tweaks left to do as far as offsets and plunge rate so I don’t leave a large ink dot where the pen starts and stops.

A987D864-E207-4869-9A61-35CB45272DB6.png

[acourtjester]

You can also mount a standard Bic ink pen in your holder. Here is the tool I use in SheetCam for the pen, I also preload the springs by moving the Z down and zeroing the pen about 0.020" on the paper to 0.0. And the plan sets the write position about -0.010" that way the pen is off the paper for the rapid movements, only touches when writing.

ink pen tool.JPG

[dtdetail]

SRdesign,
I’ve attached some files of how I make my 5/8” holes on anything thicker than 3/8” plate.

To make them, i plasma them undersize so that they’re smaller than 5/8” diameter after plasma cutting, ideally a max of 9/16” both bottom and top side diameter.

After cutting, flip the plate over so that the bottom of the plate is facing up (holes will be a touch smaller on the bottom of the plate after cutting, you want this side up).

Then simply take a 5/8” drill bit and hand drill and go to town. When the taper of the holes faces up (following directions above) the drill won’t grab nearly as much as if the plate was right side up.

Hold on tight, and when it’s time to sharpen your drill bit, decreasing the included cutting angle from 118 deg. Down to 110 deg. Helps even more.

Then use one of the Amazon/Chinese special carbide bevel tools to give the appearance they’re countersunk.

[SRdesign]

SRdesign,
I’ve attached some files of how I make my 5/8” holes on anything thicker than 3/8” plate.

To make them, i plasma them undersize so that they’re smaller than 5/8” diameter after plasma cutting, ideally a max of 9/16” both bottom and top side diameter.

After cutting, flip the plate over so that the bottom of the plate is facing up (holes will be a touch smaller on the bottom of the plate after cutting, you want this side up).

Then simply take a 5/8” drill bit and hand drill and go to town. When the taper of the holes faces up (following directions above) the drill won’t grab nearly as much as if the plate was right side up.

Hold on tight, and when it’s time to sharpen your drill bit, decreasing the included cutting angle from 118 deg. Down to 110 deg. Helps even more.

Then use one of the Amazon/Chinese special carbide bevel tools to give the appearance they’re countersunk.

That awesome man. Thanks for the suggestion. I just might go that route. I’d love for the cnc table to do most of the work for me

[SegoMan DeSigns]

If your mag drill allows it I would also tap the holes, that would save you from having to make the fixture clamps. A 3/8' would suffice for hold downs.