Chicago pneumatic CP-728 speed ratchet

[cowades206]

Any one have specification or a manual for this thing?
According to the CP web site this was their first air ratchet.
I've tried using it a few times but it has always let me down with too little torque to move anything that wasn't free running. Today I tried some cleaning and lubricating and the best I could get was to run a 5/16 bolt through a nylock, which I think is an improvement.
Any info would be appreciated.

 

[driz]

I’m not saying it’ll work but what the heck try this. Take it apart lube it up and put it back together. I’ve fixed a couple by doing just that. They are as things go painfully simple to break down.
When it’s apart really look at the ORings for the usual. Are there any seeps or hisses, what about around the trigger when it’s pulled, that sort of thing.
If the vaines are worn or broken you may be able to buy a rebuild kit[emoji1695]. Check the vanes and make sure they’re going in the right direction too. I fixed a HF special once just like that. Must have been made on Monday at the communist gulag factory and they put it in backwards[emoji75]


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[cowades206]

Thanks for the tips driz. I'm wondering how well it ever worked. Maybe that's as much torque as it ever had. If anyone out there has used one of these I'd like to know what to expect. Not in a hurry to take it apart in case there is some weird size o-ring I could damage and not be able to replace.

 

[lilredex]

I'd take it apart, there might be a simple solution to fix it......no good the way it is now?

Maybe something like my case:

https://www.garagejournal.com/forum/showthread.php?p=8631493#post8631493

 

[cowades206]

Well I guess no one whose read this has a copy of the owners manual. I tried measuring the stall torque, before I took it apart, with an old torque wrench. The set up really didn't work well. I think it measured about 5ft ft-lbs.
Took it all apart and cleaned things up . All the bearings moved well and the vanes were nice and flat. There seems to be quite gap between the vanes and the wall but all the vanes measured the same width so maybe the gap is supposed to be that large. I did replace the the o-ring on the trigger, but nothing else. Cleaned it up, put it all back together with new lube and tried measuring the stall torque again; maybe 7-10 ft-lbs if you round up. Or maybe it was still 5....with that set up you could come up with about any number you wanted.
It would run a 3/8 bolt through a nylock, so I gained a bolt size, woo-hoo!









Still hoping to find some one who has actually used one of these, or a factory published torque spec. As far as I can tell this was the worlds first commercially available air ratchet, so this might be as good as it ever worked.
I'm sure modern ones work better, or will at least smash your knuckles against something if you aren't paying attention.

 

[BlakeTheCarGuy]

I thought Chicago Pneumatic was Harbor Freights low brand. I never knew they were there own company.


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[cowades206]

You are thinking of central pneumatic which is the HF label to make you think Chicago pneumatic.

 

[Robby321]

I have a old one too. Aint used in 35 years. Never was a power house, just enough to spin the nut on then hand tight/torque..

 

[cowades206]

Thanks Robby321. That is the kind info I was searching for.
Looky what I found in the 72-73 sear catalog. 8 ft-lbs is all it was designed to do. I guess that's why there is such a large gap from the vane to the wall. I'm going to stop trying to improve it.

 

[BlakeTheCarGuy]

You are thinking of central pneumatic which is the HF label to make you think Chicago pneumatic.

Oh ok thanks for the information


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[cowades206]

OK, last post on this I think. Anyone who has searched for this on the internet has learned Chicago Pneumatic developed this tool for Ford Motor Company. It was designed to be a factory assembly tool, not a mechanic's tool, so they purposely limited the torque to 8 ft-lbs.
Seems to have been manufactured from 1969 (CP website) to about 1974-75 (Craftsman tool catalogs). By 1976 they had a newer version with 45 ft-lbs of torque. Something a mechanic might find useful.

Guess I'll throw it back in the drawer and forget about it, like I have the last 20 years.

My first 4 wheeled vehicle was a 71 F100. Maybe a CP-728 was used to assemble it. Didn't really like the truck either.