5 ms·

I've been on a MIL-DTL-38999 journey over the last few weeks. There's a lot of surplus tooling on Ebay, and they're by far the best connectors I've ever used. R

I've been on a MIL-DTL-38999 journey over the last few weeks. There's a lot of surplus tooling on Ebay, and they're by far the best connectors I've ever used. Rugged, really high pin density, and impossible to insert wrong. The prices are high for new tools, but there's tons of surplus floating around thanks to government standards. There's also solder-cup versions of a lot of the connectors so that no crimp tools are required. If you want to use the crimped versions, you'll want the M22520/1 basic tool or M22520/2 miniature tool for smaller wire gauges. You'll also need a positioner to hold the crimp in the right position within the tool (these are interchangeable for a ton of different models). You'll probably want the M22520/1-04 turret head. A Chinese company called JReady sells new crimp tools with the positioners for $300. It sounds like a lot, but it's much less than the $800 American made tool and even less than the single purpose crimp hand tools for cheaper Molex and JST connectors. One tool standard, lots of different high quality connectors!

techdragon 3y ago
I went down this road a bit too for a project where I wanted to minimise the enclosure complexity, keep everything in and out of the box to nice circular conectors... and yeah it was tempting to get into the MIL-DTL-38999 train, but I needed some high amperage low voltage DC stuff for power (it was a 3d printer project and I needed stuff like 8-14 Amps and 24-48V DC for various heaters, and a lot of these are nice for high density data, but its hard to find one that can do multiple higher power connections. I ended up giving up since I would find so many that got close but in the end the project form factor changed due to cooling issues (larger enclosure for more airflow due to insufficient fan static pressure) They are definitely cool connectors though if you only need a bunch of data and don't need the higher power density I needed at the time.
- mlyle 3y ago
  The size 12 contacts can do 15-25A. There's e.g. the Amphenol size 25 / 24 connection version, with 12 high current contacts and 12 smaller contacts. There's not too many that have a variety of pin sizes and that are military qualified, though. And it's not cheap stuff, for sure.
  - techdragon 3y ago
    Yeah I probably could have explained a bit more, I did find connections that could do it but it was never quite right in terms of a size pin count or cost trade off for this specific project. The standard absolutely has options for higher current but it comes with a smaller pool of available suppliers making those parts and thus they cost more. I wasn’t prepared to spend $50 Australian on a single pair of connectors for this project, especially since due to wiring limitations I’d have probably had to get two pairs. They firmly entered my mental toolbox as a go to for a flexible circular connector when I don’t need to join existing physical interfaces like Ethernet or higher speed USB where the signal reliability is potentially worth just using a sealed socket with matching circular screw on connector, but for the sort of thing where I’d have made up a DB9 or DB25, I’m definitely going to be reaching for these again in future (I did get a few of them and used the solder cup versions to avoid needing the crimping tools and the associated extra costs)
wtfmcgrill 3y ago
The positioners and tools are much cheaper if you buy direct from a DMC distributor. I bought the afm 8 and af8 from patlon in Canada and I got charged the MSRP on the DMC website. AF8 and the universal positioners was like 400usd when I got it and it covers like 90% of use cases. It can't do db pins though. If you buy the 38999 connectors from PEI genesis it also costs a lot less than what you would expect.
wildzzz 3y ago
We use 38999 series 1 at work for lots of things but mostly for I/O panels on thermal vacuum chambers. Offers up to 61 pins and they are extremely robust which is good for connectors that are going to get a lot of mating cycles. We typically don't use them on the products since they are so large and heavy.
83 3y ago
For those of you watching ebay - the M22520 tools are DMC (Daniels Manufacturing Corp) AF8 and AFM8 crimpers. As someone who just got into using these for an automotive application, there is a great set of lessons on wiring/crimping using these tools from High Power Academy on Youtube or $50 if you pay for their full wiring class (worth it).

techdragon 3y ago

I went down this road a bit too for a project where I wanted to minimise the enclosure complexity, keep everything in and out of the box to nice circular conectors... and yeah it was tempting to get into the MIL-DTL-38999 train, but I needed some high amperage low voltage DC stuff for power (it was a 3d printer project and I needed stuff like 8-14 Amps and 24-48V DC for various heaters, and a lot of these are nice for high density data, but its hard to find one that can do multiple higher power connections. I ended up giving up since I would find so many that got close but in the end the project form factor changed due to cooling issues (larger enclosure for more airflow due to insufficient fan static pressure) They are definitely cool connectors though if you only need a bunch of data and don't need the higher power density I needed at the time.

mlyle 3y ago
The size 12 contacts can do 15-25A. There's e.g. the Amphenol size 25 / 24 connection version, with 12 high current contacts and 12 smaller contacts. There's not too many that have a variety of pin sizes and that are military qualified, though. And it's not cheap stuff, for sure.
- techdragon 3y ago
  Yeah I probably could have explained a bit more, I did find connections that could do it but it was never quite right in terms of a size pin count or cost trade off for this specific project. The standard absolutely has options for higher current but it comes with a smaller pool of available suppliers making those parts and thus they cost more. I wasn’t prepared to spend $50 Australian on a single pair of connectors for this project, especially since due to wiring limitations I’d have probably had to get two pairs. They firmly entered my mental toolbox as a go to for a flexible circular connector when I don’t need to join existing physical interfaces like Ethernet or higher speed USB where the signal reliability is potentially worth just using a sealed socket with matching circular screw on connector, but for the sort of thing where I’d have made up a DB9 or DB25, I’m definitely going to be reaching for these again in future (I did get a few of them and used the solder cup versions to avoid needing the crimping tools and the associated extra costs)

wtfmcgrill 3y ago

The positioners and tools are much cheaper if you buy direct from a DMC distributor. I bought the afm 8 and af8 from patlon in Canada and I got charged the MSRP on the DMC website. AF8 and the universal positioners was like 400usd when I got it and it covers like 90% of use cases. It can't do db pins though. If you buy the 38999 connectors from PEI genesis it also costs a lot less than what you would expect.

wildzzz 3y ago

We use 38999 series 1 at work for lots of things but mostly for I/O panels on thermal vacuum chambers. Offers up to 61 pins and they are extremely robust which is good for connectors that are going to get a lot of mating cycles. We typically don't use them on the products since they are so large and heavy.

83 3y ago

For those of you watching ebay - the M22520 tools are DMC (Daniels Manufacturing Corp) AF8 and AFM8 crimpers. As someone who just got into using these for an automotive application, there is a great set of lessons on wiring/crimping using these tools from High Power Academy on Youtube or $50 if you pay for their full wiring class (worth it).