4 ms·

I remember back in 2000 ish I worked in R&D of a PC manufacturer and had to check the new PSUs and cases with a 'Test Finger' to make sure all the holes were sm

by Neil44 4y ago

I remember back in 2000 ish I worked in R&D of a PC manufacturer and had to check the new PSUs and cases with a 'Test Finger' to make sure all the holes were small enough. The test finger was really expensive IIRC. I also had to strap a full CRT PC to a table that rotated through various axies to measure the EMI/RFI coming from the complete setup while it was running and every now and then the straps would slip and the whole thing would crash down and make a big bang and a mess. Good times.

auxym 4y ago
We often use stepped "reach gauges" for machine guards used in manufacturing and such: https://www.mcmaster.com/gauges/machine-guard-safety-gauges/ https://www.mcmaster.com/gauges/machine-guard-safety-gauges/ Not too expensive though.
Sohcahtoa82 4y ago
... Why was the "test finger" so expensive? What was it made of? Why not just use a $3 wooden dowel rod from Home Depot?
- JohnFen 4y ago
  Very likely they just wanted or needed certification-level accuracy. A wooden dowel would be very inaccurate for a bunch of reasons, including that its dimensions will change with humidity. Test fingers and the like are very expensive because of the serious precision they have to be machined to, and are made of expensive materials to minimize dimensional changes the result from environmental variations and use.
  - JohnBooty 4y ago
    I imagine they're small manufacturing runs as well. How many ISO-certified test fingers do they sell per year? Adds to the cost.
- Neil44 4y ago
  Maybe they just told me that to stop me loosing it all the time!
- Kon-Peki 4y ago
  All that cost savings goes out the window the first time you get sued ;) But also keep in mind that test fingers are used for more than just seeing if it can poke through a screen. Way way way back when I worked in the auto supplier industry, we needed to test to make sure the auto-up windows and auto-closing minivan doors would actually not cut your finger/hand/leg off. We always used pencils as a first try. They break a lot easier than a dowel rod of the same diameter. If we were happy with the results, we'd get out the test finger. If it looked a little iffy, we'd suggest that the engineers should use their own fingers if they were really confident in their work.
- queuebert 4y ago
  You can buy small stainless steel cylindrical gauges accurate to 0.0001" for not much more than that.
zh3 4y ago
BSI standard for test finger appears to have been withdraw [0] in favour of EIC standards. You can still get test fingers on Amazon though [1]. [0] https://knowledge.bsigroup.com/products/standard-test-fingers-for-checking-protection-against-electric-shock-and-mechanical-hazard/standard https://knowledge.bsigroup.com/products/standard-test-finger... [1] https://www.amazon.co.uk/GOWE-IEC61032-IEC60529-Probe-Finger/dp/B01GMGFNIE https://www.amazon.co.uk/GOWE-IEC61032-IEC60529-Probe-Finger...

by Neil44 4y ago

auxym 4y ago

We often use stepped "reach gauges" for machine guards used in manufacturing and such: https://www.mcmaster.com/gauges/machine-guard-safety-gauges/ https://www.mcmaster.com/gauges/machine-guard-safety-gauges/ Not too expensive though.

Sohcahtoa82 4y ago

... Why was the "test finger" so expensive? What was it made of? Why not just use a $3 wooden dowel rod from Home Depot?

JohnFen 4y ago
Very likely they just wanted or needed certification-level accuracy. A wooden dowel would be very inaccurate for a bunch of reasons, including that its dimensions will change with humidity. Test fingers and the like are very expensive because of the serious precision they have to be machined to, and are made of expensive materials to minimize dimensional changes the result from environmental variations and use.
- JohnBooty 4y ago
  I imagine they're small manufacturing runs as well. How many ISO-certified test fingers do they sell per year? Adds to the cost.
Neil44 4y ago
Maybe they just told me that to stop me loosing it all the time!
Kon-Peki 4y ago
All that cost savings goes out the window the first time you get sued ;) But also keep in mind that test fingers are used for more than just seeing if it can poke through a screen. Way way way back when I worked in the auto supplier industry, we needed to test to make sure the auto-up windows and auto-closing minivan doors would actually not cut your finger/hand/leg off. We always used pencils as a first try. They break a lot easier than a dowel rod of the same diameter. If we were happy with the results, we'd get out the test finger. If it looked a little iffy, we'd suggest that the engineers should use their own fingers if they were really confident in their work.
queuebert 4y ago
You can buy small stainless steel cylindrical gauges accurate to 0.0001" for not much more than that.

zh3 4y ago

BSI standard for test finger appears to have been withdraw [0] in favour of EIC standards. You can still get test fingers on Amazon though [1]. [0] https://knowledge.bsigroup.com/products/standard-test-fingers-for-checking-protection-against-electric-shock-and-mechanical-hazard/standard https://knowledge.bsigroup.com/products/standard-test-finger... [1] https://www.amazon.co.uk/GOWE-IEC61032-IEC60529-Probe-Finger/dp/B01GMGFNIE https://www.amazon.co.uk/GOWE-IEC61032-IEC60529-Probe-Finger...