Good day to all. Few years ago I wrote the instructable, titled: "Laser Cutting Table - the Better Version". The reason for that project was my search for a good laser cutter/engraver table, which in my opinion were not available (see the reasons, I listed, in that instructable so it makes sense to you), but those available were very pricey. That table served me very good, but it was not easy to do/replicate for many people and even to myself due to needed tools and hands-on time required. This summer I ripped the kanthal wire by accident and instead of repairing the table, I had an idea how to made another one. I'm very satisfied with the table and decided to share another instructable with you. It requires very minimal amount of tools; cheap/widely available parts; and a very little time. End result: very flat/parallel/even surface to hold your work-piece; easy gas evacuation, not possible with honeycomb tables; no reflective damage to the bottom sides of your work-pieces, not possible with any other types of tables; uses kanthal wire, high melting point; cheap and repeatable process.
Short description: table's frame made of 2020 aluminum extrusion. Surface is made of kanthal wire wrapped around ~40 small diameter bearings and fixed with two handle screws at opposite ends. This is it. It may not make sense by reading, but please look at the pictures and you will see how easy it is.
This is what you need:
1. 2020 aluminum extrusion 4 pcs set. https://www.aliexpress.com/item/32861402365.html?s...
2. 2020 corner brackets 4 pcs. https://www.aliexpress.com/item/32922071230.html?...
3. 3x12x4mm V623 bearings 50 pcs set. https://www.aliexpress.com/item/32816393349.html?s...
4. M3 12mm bolts 50pcs set. https://www.aliexpress.com/item/32981714992.html?...
5. M3x6x1mm nylon spacers 100 pieces set. https://www.aliexpress.com/item/33021883302.html?...
6. 20s M3 block nuts 100 pcs set. https://www.aliexpress.com/item/32825357262.html
7. Handle screw M5x25mm x2 pcs. https://www.aliexpress.com/item/32870272717.html?...
8. 2020 M5 block nuts x2 pcs. https://www.aliexpress.com/item/32706766495.html?...
9. Kanthal wire 100 in 24 Gauge. https://www.amazon.com/gp/product/B07CHSG169/ref=p...
10. M5 bolt x8 pcs. https://www.aliexpress.com/item/32966157667.html?...
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Step 2: HOW TO
This is pretty much a self explanatory process, if you looked at those pictures. So I'll quickly summarize the steps:
1. cut the extrusion to desired length: for my 300x600mm table I cut 30cm x2 and 55cm x2
2. place those pieces on flat surface; align those cut pieces together; and bolt them together using those angle/corner brackets; M5 10mm bolts; and 2020 M5 square nuts. Do it on flat surface so whole table is as flat and square as possible.
3. measure and decide what distance you like between the wire and mark the extrusion's upper and lower sides. I did 25mm. One thing to note. If you do 25mm as I did, the wires will not be parallel to each other, which is totally fine with me. If you desire you may place the bearings closer, but it will be difficult to tighten the wire at the end
4. slide the right amount of 20s M3 square nuts in the upper and lower extrusions. Place one nylon spacer onto M3 12mm bolt; place a bearing onto the M3 bolt; tighten the bolt to the square nut lightly so it may move along the extrusion
5. align those bearings to your marks and tighten them hard enough. The bearing should be spinning with little or no play
6. use a drill press or a hand drill and make 1, 2, or 3mm hole close to the handle of the M5 handle screw itself. I have a mill available and shaved some thread and used center pin punch tool to start drilling, but you may use any available file and then center punch tool to achieve same results. Those available everywhere. Harbor Freight is probably cheapest alternative.
7. decide where the M5 handle screw will mounted and drill 6mm or larger hole through the extrusion at that spot. It will give you more room for tightening the wire later. Slide 2020 M5 square nuts from each end of lower extrusion; put M5 regular nut onto the M5 handle screw and screw it closer to the drilled hole. Screw the handle to the 2020 M5 square nut in the lower extrusion.
8. slide kanthal wire in one of the M5 handle screw's hole and do a couple of winds around it to keep it in place
9. wind the kanthal wire around those bearings and when done, slide the end into the other M5 handle screw hole and slightly tighten
10 start tightening the M5 handle screws and use your fingers to tighten the wire starting from center and moving to the side
11. now tune your "harp" to a desired tone ;-)
12. place the table on flat surface to make sure the table itself is flat and if not, bend it as desired by placing the opposite corners against any surface or even your leg and applying some force.
Happy cutting/engraving. Vlad