Looking for a DSR regulator to build?

Matt F. · May 26, 2011

maknwar · May 27, 2011

The mathesons are great regulators. I have two and they are solid. Just remember to check if they need fine threaded cga 320 stems.

Matt F. · May 27, 2011

maknwar;68037 said:
The mathesons are great regulators. I have two and they are solid. Just remember to check if they need fine threaded cga 320 stems.

Most of the older Harris built regulators (Model 8s, etc.) need the fine threaded CGA nipple/stem.

Here is what I initially wrote on my experience (with the help of others):
As some of you know, I recently aquired a like-new Matheson Model 8-580. Thanks to the help of S&KGray at Barr's site, I was educated that I needed a fine thread CGA nipple, not the standard 1/4" npt that Victors and other regulators use.

According to my Jim at Regulator and Torch Repair, Matheson Model8s are made by Harris, who uses a strange inlet port thread. The output on these Mathesons is 1/4 npt, so you don't have to worry about post body kits.

Here is the link for the correct part:
http://www.regulatortorchrepair.com/store.php/products/cga-320ft-nut-and-nipple

You can also order them from Western Enterprises via Airgas: part number CO-7 (thanks again to S&KGray for the part number)

You use a regular CGA 320 nut with this fine thread nipple.
Below are some pics.

The difference between 1/4" npt and the 1/2" 27 thread:

Here is the old CGA 580 next to the new CGA 320

Here is the new CGA 320 installed on the Matheson Model 8-580

maknwar · May 27, 2011

The stems are about $20 too, so include that into the build price. Worth it IMO cause you can get a matheson DSR for cheap.

Left C · May 28, 2011

Matheson has a very good line of two stage regulators. I'm only familiar with the 8-320 which is one of their tri-gas models of which the CGA-320 model is one of them. There is one for inert gas with a CGA-580 fitting. I waited until one with the CGA-320 fitting came along and purchased it.

Matt F. · May 28, 2011

Left C;68077 said:
Matheson has a very good line of two stage regulators. I'm only familiar with the 8-320 which is one of their tri-gas models of which the CGA-320 model is one of them. There is one for inert gas with a CGA-580 fitting. I waited until one with the CGA-320 fitting came along and purchased it.

Also the 3104C is nice...I think Fordtrannyman had one. I think it's the high purity version of the Model 8.
I think the Matheson 3100 or 3800 series is stainless steel (forgot which one) like the SGTxxx series for corrosive/toxic gasses.

Looking for a DSR regulator to build?

Matt F.

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maknwar

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Matt F.

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maknwar

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Left C

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Matt F.

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