cnc workholding

Nov. 17, 2023

Harbor freight has an affordable set:

https://www.harborfreight.com/58-piece-combination-step-block-and-clamp-set-3-8-eighth-inch-16-nc-studs-1-2-half-inch-clamps-5952.html

Printable version of the harbor freight item above: https://www.thingiverse.com/thing:6308416

Here’s a similar idea using 3d printed long clamps. Printing them is a good idea in case you crash an end mill into it accidentally, but milling some out of Delrin or ABS might be stronger and more long lasting. https://www.thingiverse.com/thing:4168018

Another similar clamp that you would use the t-slots in the cnc’s table with, but same advice, purchase or mill out of aluminum or even plywood, if possible :

https://www.thingiverse.com/thing:4769680

Another long clamp. The idea is to keep the metal parts away from where the tool head is, in case of an accidental crash. 

https://www.thingiverse.com/thing:4948898

Aluminum versions are available, and arguably balance cost to strength well: 

UTOOL 2 Pack T-Track Hold Down Clamps Kit, 6-1/3″ L x 1-1/5″ Width, Heavy Duty Anodized Clamps for Woodworking, Starlight Blue 

https://a.co/d/f8q8dcn

Similar: 

O’skool Multi-Positionable T-Track Hold Down Clamp Kit for CNC Router Clamp, Metalworking and Woodworking T-Slot T-Track Clamp,2 Pack

https://a.co/d/9n5sk7x

Similar: 

T-Track Mini Hold Down Clamp Kit, 2Pcs Aluminum Alloy M6 T-Slot Hold Down Clamp, CNC Router Clamps for Woodworking and Metalworking-3.2″Lx1″Wx2.7″H

https://a.co/d/8eD86wi

For higher risk but more repeatable fixturing, a cross sled vise can work, with the risk being crashing your end mill into metal. It definitely can work for special tasks but might not be a good generalist solution.


Nov. 19, 2023

Horizontal cnc jig results

Alright, this jig I made to hold the dremel flex shaft horizontally worked *beautifully*. I hand-programmed the gcode, and I obviously have some more fine tuning to do, but overall, I’m on the right track!

Here’s the nice clean hole the jig produced. Adjustments required, but almost there.

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Here’s the jig that’s holding the case down.
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Video of the jig in action:

Horizontal cnc mod

Alright so one of the last hurdles to jump before I’m ready for production is being ready to cut holes in the sides of the enclosures for the USB cable. I’ve been doing this by hand with a dremel with *extremely* variable results. :-/ So, when my pal Jim was up for a visit earlier this year, he helped brainstorm on some ideas and this was the concept we ended up with. Using the dxf files for the cnc machine, I was able to locate the hole pattern and design a new piece that will bolt on to the existing z axis gantry. This new piece, with the help of some shape lock, securely holds a flex shaft attachment for a dremel… Which in theory should let me jig a beatseqr enclosure to the table and cut nice clean square holes without and problems or sloppiness. In theory. But man, I’m getting really close to having the infrastructure in place to do what I want. Getting pretty exciting up in here!!

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Solving problems: LRF support

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When I have a bit more time, I’ll post a video, but I just couldn’t locate mechanically fastening LRF’s to the specs I need. So I drew up a concept on some paper, redrew it in illustrator, exported it to dxf, imported it to sheetcam, and cut a casting mold. I used the smooth-on shore hardness 40 silicone since I’ve decided it’s too tough to work with for my buttons… Turned out pretty good! Maybe a little too tall. But it will be easy enough to slice off this mold and try again. I’m loving the time from concept to iteration. Very fast!! And I’m not committed to hundreds of failed designs. Just a couple few. I’ll even use these for experimental projects.

Version 4.51 silicone button array development

Research and development continues with cutting (and recutting, and recutting) the new silicone button casting mold. I’ll be verifying the dimensions tonight, but things are moving along nicely. I may be able to get one of the new v4.51 boards close to fully assembled. Which I am very
much looking forward to. The last major task is to engineer a jig to hold a dremel flex shaft that will attach to my cnc machine. This will let me cut a hole for the USB jack with precision and repeatability on the case. After that, I’ll be able to kick into a higher gear for producing units and kits. Whew!

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Fail. 🙁

 

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a sea of machineable wax chips. This mold would end in disaster.

 

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Present and future casualties of my learning process

 

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Try number 3. This one went well after 5 days of chipping away at it.

 

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Smooth-on dragonskin-30, a two part a/b platinum cure silicone, in the happiest place on earth: a beatseqr button mold

 

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It. Looks. GOOD!