Wire forming techniques used in making the VERSA-OHM Decade box - Page 1
Forum section: electronics / projects

author: robrenz
author_rank: Super Contributor
timestamp: March 19, 2015, 03:12:19 am
content: This is a video covering the wire forming techniques I used in making my VERSA-OHM decade resistance boxes. Hopefully there will be some ideas and tricks that you find useful.

author: Vgkid
author_rank: Super Contributor
timestamp: March 19, 2015, 05:13:20 am
content: That is an impressive video, thanks for posting it.

author: es
author_rank: Contributor
timestamp: March 19, 2015, 07:16:24 am
content: Wow, that's serious craftsmanship, I'm really impressed.I couldn't find info on the Versa-Ohm box, is it a product you're planning to sell?

author: robrenz
author_rank: Super Contributor
timestamp: March 19, 2015, 11:48:10 am
content: Quote from: es on March 19, 2015, 07:16:24 amIt is a very small double eight decade resistance box. I am making a run of 25 of them. I don't know what the price is going to be but they wont be cheap. There is an extreme amount of manual labor in making them as will be seen in more videos of the design and construction.

author: krivx
author_rank: Frequent Contributor
timestamp: March 19, 2015, 11:59:31 am
content: I really like these posts, it's a look into disciplines I don't get to see much of. Silver soldering looks quite useful, I might have to look into that

author: george graves
author_rank: Super Contributor
timestamp: March 19, 2015, 12:04:49 pm
content: Awesome!!!!!Amazing video. The custom jigs, flag and the wire bending is insane. The silver solder of parts. All the machining. Really crazy stuff. Hats off.You wire straitening technique is something we've all done. I find that a quick "snap" does the job a bit better. But maybe you have an opinion on that.I couldn't get a good fix on the end product. But I think you've show it before no? A project box with jumpers to make a resistor sub box. IIRC.So, what I don't understand (I'm missing something) is why go to the length of all that amazing wiring, and use header pins as an interface rather then some beefy switches? Would love to hear some of your design decisions.

author: pmcouto
author_rank: Unknown
timestamp: March 19, 2015, 12:11:39 pm
content: 23:18 of pure art!Thank you robrenz.

author: con-f-use
author_rank: Unknown
timestamp: March 19, 2015, 12:46:55 pm
content: Awesome as usual. However, I'm missing the context a bit. What do you want to achieve and why do you need this sort of precision in the mechanical construction?

author: dom0
author_rank: Super Contributor
timestamp: March 19, 2015, 12:52:21 pm
content: Looks like equal-length wiring to me.

author: robrenz
author_rank: Super Contributor
timestamp: March 19, 2015, 01:14:27 pm
content: Yes equal length wiring. All residual resistances are calibrated as shown on the picture of one of the Versa-Ohm instruction sheets. This allows you to add these values if you are trying for highest accuracy.

author: vinicius.jlantunes
author_rank: Regular Contributor
timestamp: March 19, 2015, 01:15:19 pm
content: This is very cool!

author: zapta
author_rank: Super Contributor
timestamp: March 19, 2015, 01:15:51 pm
content: Quote from: robrenz on March 19, 2015, 11:48:10 amIs this a low resistance high current box with the wires acting as resistors?Is investing how the standard tools are just a starting point for you. It's a different kind of thinking.

author: robrenz
author_rank: Super Contributor
timestamp: March 19, 2015, 01:30:19 pm
content: Quote from: zapta on March 19, 2015, 01:15:51 pmThese wires are only to connect the .025 jumper pins to banana jacks. Here is a picture showing how it uses jumpers to set what resistance you want.

author: Chipmunk
author_rank: Contributor
timestamp: March 19, 2015, 02:23:40 pm
content: The tool making is if anything more fascinating than the eventual construction but it's a close run thing. This is most awesome, thank you for posting!

author: georges80
author_rank: Frequent Contributor
timestamp: March 19, 2015, 06:27:58 pm
content: Great to see a machinist at work in his skill area. Appears most of the 'fun' is building itThough, I've never owned a resistance box etc and can't imagine any application that *I* would ever need one. Given most things I work with are surface mount and layout critical any long wire leads to an external resistance (or capacitor) box would totally mess up the operation of the circuit.cheers,george.

author: nanofrog
author_rank: Super Contributor
timestamp: March 19, 2015, 08:07:08 pm
content: Amazing work as per usual.

author: SArepairman
author_rank: Frequent Contributor
timestamp: March 19, 2015, 08:16:07 pm
content: im contemplating mailing you a gallon ofhttp://www.okeeffescompany.com/working-handsgood video though, hate the close ups of your hand injuries though

author: quarks
author_rank: Frequent Contributor
timestamp: March 20, 2015, 06:20:50 am
content: I wish my english would be better, so I could express the superlative words for your amazing work.Thanks a lot for sharing!!!

author: robrenz
author_rank: Super Contributor
timestamp: March 20, 2015, 12:47:22 pm
content: Thanks to everyone for your encouraging comments. Its always nice to have your work appreciated.Quote from: george graves on March 19, 2015, 12:04:49 pmI wanted to build a decade box that was versatile enough that people would actually want to use it. This istwoseparate 8 decade units in one box and each decade is a string of 10 resistors with a socket connection at each junction. This allows multiple resistances to achieved simultaneously and paralleling of decades for higher wattage etc, etc. There will be videos of it in action and the Video below shows the general layout in the beginning before going to making the Kelvin jacks.Quote from: SArepairman on March 19, 2015, 08:16:07 pmMy hands are fine, they look worse than they are. That is all callous skin and the cracks don't go into live flesh. I use a dremel drum sander to grind the callouses off every so often.... I guess I should do that before shooting videosThese residual resistance value measurements are why I had to make Kevin banana jacks and .025" kelvin probes and sockets to measure the values. Video of the design and construction of them below.Making Kelvin Banana Jacks and .025" Kelvin pins and sockets. It shows the Versa-Ohm in the beginning for a few minutes.

author: robrenz
author_rank: Super Contributor
timestamp: March 23, 2015, 11:56:05 am
content: Bump