Jim:
I may need to go back to my message and see my typos.
I was specifying 5HP compressors, not 5CFM. At least I
meant to. I agree that 5CFM is almost useless for any kind
of auto shop work.
But your comparison of your 5HP compressor to mine
illustrates the issue I have with using HP ratings to
compare compressors. The important spec to go by is the CFM
rating. Is yours an oiless? I believe those are typically
over rated with respect to horsepower, as in the little
Harbor Freight pancake compressor I got a while back that's
supposed to be 2HP but can run, according to HF and in
actuality, on a 15A 120V line. In other words, not a "real"
2hp. I have a 1HP Sears (my 30 year old one) that could
never run on a 15A line.
But the pancake was acquired to be portable and to run my
nailers. 4CFM is enough for that.
And then the 5HP gas models bring a whole new perspective to
these specs.
There may be more involved with the type of pumps on these
as well. Both my 1HP and 5HP Sears units are twin
cylinder. I have never had a two stage machine, but my
nephew had what was supposed to be a two-stage 5HP machine
and it couldn't keep up with a pressurized sandblaster.
Mine (the 5HP) has no problem with this at all. I know
two-stage develops higher pressure, but maybe sometimes
that's at the expense of CFM.
Maybe this time, my CFMs and HPs are all in the right place.
Jim
James Gruber wrote:
> Jim, 5 CFM doesn't get it. I got a nice Capmbell- Hausfeld
> 5 HP, 30 gallon, but its peak output of 5.2 CFM isn't
> enough. Any of the decent air tools take more than 5 CFM
> to work. Things like air powered rotary sanders, air
> chisels, things that require lots of power all want more
> than 5 CFM. With filter and traps oil is the way to go.
> Next one will be bigger, stationary, larger tank so the
> compressor doesn't run so much.
>
> Jim Gruber
> Bugsy '68 Sprite (future Bugeye in disguise)
> Dayton, OH
>
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