[Devastator]

Do you still have the DXF files you can share? Looking to make me a drag knife. Thank you

They were not my files and I haven't been given permission to share. I'd contact Brian @ Grunblau: Brian Oltrogge | Gr

[Devastator]

Picked up another harmonic drive for my A axis from ebay for $75 shipped. Stepper is NEMA 23, 1000 steps per revolution, harmonic drive is 1:50 ratio. So 50,000 steps per revolution X 8 microsteps is 400,000 steps per revolution. Pretty crazy resolution, should be smooth as butter. Not sure why it says "5-phase". It's just a standard 5 wire stepper as far as I can tell.

[louieatienza]

Picked up another harmonic drive for my A axis from ebay for $75 shipped. Stepper is NEMA 23, 1000 steps per revolution, harmonic drive is 1:50 ratio. So 50,000 steps per revolution X 8 microsteps is 400,000 steps per revolution. Pretty crazy resolution, should be smooth as butter. Not sure why it says "5-phase". It's just a standard 5 wire stepper as far as I can tell.

Wired differently inside. There are 5 phases instead of 2, so the rotor turns (moves) 2-1/2 times less than a 2-phase stepper. So they're usually 500 steps/rev (.72deg/rev) or 1000 steps/rev (.36deg/rev) as opposed to 200 steps/rev (1.8deg/rev). Needless to say, you need a 5-phase driver to run that stepper...

[Devastator]

Wired differently inside. There are 5 phases instead of 2, so the rotor turns (moves) 2-1/2 times less than a 2-phase stepper. So they're usually 500 steps/rev (.72deg/rev) or 1000 steps/rev (.36deg/rev) as opposed to 200 steps/rev (1.8deg/rev). Needless to say, you need a 5-phase driver to run that stepper...

Thanks, that makes sense. I'll probably just swap out the stepper then. I imagine those drivers are either hard to come by or expensive, or both. Mostly just bought it for the harmonic drive. Pretty cheap for a NEMA 23 HD.

[Devastator]

I bought this driver for it. Just slightly more money than swapping the stepper. I am currently using a three axis driver and have been doing cable swapping with my Y every time I need to use the rotary axis. This will take care of that issue.

[LS120]

interesting idea do you think??

https://www.facebook.com/guilherme.p...3164611045789/

[Devastator]

interesting idea do you think??

https://www.facebook.com/guilherme.p...3164611045789/

Depends on what you are building. Steel bearings on aluminum will wear. And if that part is subjected to torsion, it will twist due to the amount of threaded rod and thin aluminum tubing. Keeping the rails parallel might also be a challenge. It could be perfectly suitable for a laser cutter with low forces, but I would not consider it good for a router.

[Devastator]

So anyone who is on the fence about building a DIY machine from junk or other repurposed materials.....It's just been a few years since mine was finished. I've been machining aluminum rocket parts for the US military, in quantity. Sometimes you just never know where the path will go.

[LS120]

yes i know its too light for router but for laser or 3d-printer maybe.... i'm still stalled as no funds to complete at this time but trying real hard to get some

[Devastator]

yes i know its too light for router but for laser or 3d-printer maybe.... i'm still stalled as no funds to complete at this time but trying real hard to get some

That design is actually more expensive than just steel pipe and angle iron. It takes 12 bearings and a lot of threaded rod, whereas with pipe you could use 8 bearings and 8 bolts. Or if you utilized the method that I call the "clothespin method" like on the X carriage of the Solsylva, you'd only need six bearings per carriage for full constraint. And steel is cheaper and stronger than aluminum. Or you could spend just a bit more on bearings and use V-bearings which would allow you to only use 4 bearings per carriage, but it simplifies the whole thing because your linear rails can be steel plate that is ground to a V.

So all of these will be close in cost, but the rigidity will be much better with the latter options. By all means, don't let anything I say discourage you from starting with what you have. That's what my previous post was about. It is common on this forum to get the impression that if you can't afford profile rails and ballscrews that you are not going to have a machine that can do quality work. If I had let that get to my head, I'd still be saving for parts.

At the very least, you will have a machine to learn on and make upgrades to.

[lael]

Thanks! I used vinyl and rubber cement. Here's a couple more.

Wow - your anodisation looks amazing. How do you do this? Do you have a documented process you followed?

[Devastator]

Wow - your anodisation looks amazing. How do you do this? Do you have a documented process you followed?

Thank you!! It took a ton of experimenting. Because it is a form of art, I had to research the technique for years. Nobody would share their methods, most said they were proprietary, others said their methods were patented. So I experimented and made a lot of mess. After I got some working methods, I then understood why no one would just tell me their secrets. Maybe I should write an e-book.

[lael]

Yeah, seriously want to know now! PM'd you

[manofmanyhats]

... Maybe I should write an e-book.

I'd buy it...Just sayin.

[LS120]

why not.. try get back some the costs in learning..

[lael]

well... that makes three of us

[Devastator]

A good article in Popular Mechanics about the US Navy ramjet missile I machined the fin cans for on the Solsylva. Navy Builds Ramjet Missile with Model Rocket Engines and a Credit Card

[jlowe1224]

So I am at college and at my university I have unlimited free access to materials, most of which is a ton of aluminum stock and steel, as well as water jet, CNC milling machines and very large gantry. This gave me the idea that I can upgrade my machine at home for no cost other than my time, so my question is what should I upgrade on my solsylva first, mostly to minimize backlash on all axis? Or I could probabaly build a completely new machine but that would take too much of my time making the parts.

[Devastator]

So I am at college and at my university I have unlimited free access to materials, most of which is a ton of aluminum stock and steel, as well as water jet, CNC milling machines and very large gantry. This gave me the idea that I can upgrade my machine at home for no cost other than my time, so my question is what should I upgrade on my solsylva first, mostly to minimize backlash on all axis? Or I could probabaly build a completely new machine but that would take too much of my time making the parts.

If you have access to that, I'd say go for it. Solsylva is only for people with no money or resources, IMO.

[Devastator]

A 7075 aluminum rocket fin with bevels and polish. Finish pass was 1/8" ballnose with 5% stepover.