Where to buy steel plates to fit into the cutting bed?

[Gene Uselman]

It doesn't seem that Russ is using his acrylic pin bed much lately- often acorn nuts on the steel bed. A lot depends on what you are doing on your laser- he mostly does experimentation. If you are producing products your needs will be different. The power of the machine makes a difference also.

[Tim Mellor]

Slightly off topic.

Different pin bed style. I saw a while back in one of the other forums, a guy was using small magnets and drywall screws to make an infinite pin bed on a steel plate.

I haven't made an acrylic version like Russ yet, and I'm considering that option.

My Acrylic pin bed was fairly short lived in use as it developed a curve. With more care on Laser power it would have extended the life but in the end I went to 4mm Aluminium and 2 x 25mm long pins. Still need to drill out the rest of the holes but working well on larger blanks as is. Masking taped the sheet then engraved the mark out, center punched and removed tape.

Could be done on a larger Laser similar to Russ's idea with several of them then moved around as needed, my baby is fine with one and the Acrylic frame and edge index system sits 3mm above the pins.

[Gene Uselman]

Steel sheeting is available with .125 perforations every inch or so [in the US] and roll pins are available in that size. I have made a couple 12x12 inch panels with on having more pins for smaller parts. I haven't used them much lately. I also have wood standoffs for my honeycomb panels to lift the material an 1/8" off the surface which usually eliminates the flashback, If I don't get to aggressive with the cut power.

[Hank Morgan]

I use a piece of 0.030” (22 gauge) steel. I removed the honeycomb bed which is not very flat and put the steel on the support bars.
The sheet steel has a couple of holes drilled in it around the edges so it can be pinned to the support frame and reliably located in place.
I strapped a Sharpie to the laser head and asked it nicely to draw some grid lines on 1 inch spacing's to help make it easier to position things square with the laser.

I use magnets, either with or without short deck screws on top to support the work. The grid drawn on the metal aids in putting put the supports in locations where the laser is less likely to cut directly over them.

Looks like this. You can see 6 of the magnets stuck on the surface.

[Jeffrey Aley]

I strapped a Sharpie to the laser head and asked it nicely to draw some grid lines on 1 inch spacing's to help make it easier to position things square with the laser.

Very cool idea!

[Hank Morgan]

"Strapped a Sharpie to the laser head" is a bit of an oversimplification but pretty much what it amounts to.

I actually made a holder for Sharpies years ago to use with the CNC router for drawing stuff.
It's a short metal tube that a sharpie jams in to, and that tube slides snugly inside a second tube that has a mount to bolt it to the CNC machine.
The outer tube has 3 little tabs cut in it at the bottom and bent inward so when it's picked up the inner tube and Sharpie can't slide out the bottom. That way it can be lifted during travel moves so it doesn't leave a mark and when it's down the sharpie can slide up and down under it's own weight so it works on uneven surfaces without messing up the felt tip.
I just strapped the whole assembly to the laser head with some electrical tape for this job.

I really like the grid marks. Very handy for alignment.

[Jeffrey Aley]

"Strapped a Sharpie to the laser head" is a bit of an oversimplification but pretty much what it amounts to.

I actually made a holder for Sharpies years ago to use with the CNC router for drawing stuff.
It's a short metal tube that a sharpie jams in to, and that tube slides snugly inside a second tube that has a mount to bolt it to the CNC machine.
The outer tube has 3 little tabs cut in it at the bottom and bent inward so when it's picked up the inner tube and Sharpie can't slide out the bottom. That way it can be lifted during travel moves so it doesn't leave a mark and when it's down the sharpie can slide up and down under it's own weight so it works on uneven surfaces without messing up the felt tip.
I just strapped the whole assembly to the laser head with some electrical tape for this job.

I really like the grid marks. Very handy for alignment.

You might also add a strip of something along the zero lines so that you can push material into the corner to align it. Like aligning a piece of paper on the glass of a photocopier. I find that it's really handy if I want to do repeated cuts.

[Dave Vigness]

Love the Sharpie idea for the grid. I'm still using the honeycomb, but fighting bed space because of the edge frame. Luckily I have a 1" ladder tube frame under so I'm wide open for replacement beds. Some type of pin bed looks good at the moment, but that is subject to change up to, and maybe after, installation day.

[Doug Fisher]

Just to follow up, I bought a sheet of 20 gauge .036 cold rolled steel from Metal Supermarket for about $28.

Steel Sheet on Laser Bed 2.jpg

I was skeptical that my honeycomb drop-in cutting bed was completely square and was also worried about cutting variance by Metal Supermarket, so I had the sheet cut 10 mm smaller than my bed in each direction and I am glad I did that. They cut the sheet very accurately but my honeycomb frame is not square.

The 20 gauge steel seems like a good thickness. Not too heavy but should not warp/bend if handled with reasonable care.

As a previous poster mentioned, there are three Metal Supermarkets in my area. They are franchises and the level of service and competence varies between locations. I didn't have confidence in the first place I called since they said they could not supply flat material because it gets very warped when sheared. The second place wasn't worried about warping although the guy became very agitated and wasn't willing to work with me when I quoted my cut dimensions in mm (even though their website, which wasn't able to complete order payments, allowed quotes in mm). When I quoted in inches with decimals, he still refused to cooperate. It was only when I did the calculations myself to convert to the nearest 16ths of an inch that he agreed to do the order.