Has anyone built/upgraded their compressor DIY style?

[lowkee]

So I have owned a 5HP Craftsman direct-drive oil-less 25Gal compressor since new (~16 yrs) and it still runs fine, but my ears seem to enjoy the noise of it less and less, and some of my tools simply tax it too much. Being so old, the pump is not very efficient; It only gets 7CFM @ 90PSI.

Seeing as the tank is still in good shape and the motor is a true 5HP GE which can be wired to 220V, I'm hoping to do the following:

-Remove the pump assembly
-Pivot the motor 90 degrees
-Wire to 220V
-Add a v-belt pulley to the shaft
-Change the pump over to an oiled twin pump belt driven setup

Has anyone done this before?
Is it worth the effort?
Is there a formula to convert motor HP to CFM output?

I hate the thought of selling this for $150, then spending $600 for a cheezy compressor with a weaker motor and a tank 3 times bigger than I need, just to get higher CFM output.

 

[rbh]

Re: Has anyone built/upgraded their compressor DIY style?

How about a rebuild, those plug/pistons wear out (most are even ringless)
and add a big muffler to the exhaust port/ports.
an oversize intake filter/air filter.
everything helps.

 

[bruceb58]

Re: Has anyone built/upgraded their compressor DIY style?

I don't blame you changing to an oiled pump. I would never buy one of those oilless pumps. My suggestion is just to sell it as is and buy another one. I really doubt you will get $150 for it though.

Go buy one of the harbor freight compressors. Get a 20% coupon and they are very reasonable. That is what I am going to do when I upgrade my 110 compressor to 220.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=65903
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=34887

Are you sure you get even 7CFM at 90PSI. That seems high for a 110 compressor. Not that you can measure it but seems very high.

 

[bruceb58]

Re: Has anyone built/upgraded their compressor DIY style?

an oversize intake filter/air filter.
everything helps.

Unfortuantely, most of the noise is not due to the air intake.

 

[rockyrude]

Re: Has anyone built/upgraded their compressor DIY style?

Before you get carried away, look closely at the motor, if your oiless is like mine they made a custom motor shaft that was shorter than normal to be able to bolt the "crank" for con-rod to. I wanted to do the same thing but when I added the motor cost and the cost of a decent piston pump, replacement of the whole thing started looking better. I do a fair amount of painting so I just put the old tank in series with my paint gun to soften the start surge when I'm painting.

 

[bruceb58]

Re: Has anyone built/upgraded their compressor DIY style?

Also, don't go by the HP rating of a motor. The 5HP they put on it means absolutely nothing.

 

[lowkee]

Re: Has anyone built/upgraded their compressor DIY style?

Well, you guys deflated my optimism in short order . I'll take a look at the motor to check for shaft length. I recall reading somewhere about someone else complaining about shaft length as well. And here I thought 16 years ago I was buying the only compressor I'd ever need..

 

[bruceb58]

Re: Has anyone built/upgraded their compressor DIY style?

Well, you guys deflated my optimism in short order .

That's what we're here for!

 

[JustJason]

Re: Has anyone built/upgraded their compressor DIY style?

Check out the Home depot branded husky compressors. I have a 7HP 60 or 80 gallon (can't remember) that I bough brand new for 399 5 or 6 years ago. It is only a single stage, but the only tool that really eats up the air is the DA. I'm pretty sure they are repainted Campbell haufelds.

 

[Bob_VT]

Re: Has anyone built/upgraded their compressor DIY style?

Check out the Home depot branded husky compressors. I have a 7HP 60 or 80 gallon (can't remember) that I bough brand new for 399 5 or 6 years ago. It is only a single stage, but the only tool that really eats up the air is the DA. I'm pretty sure they are repainted Campbell haufelds.

Husky is a rebranded Campbell Hausfeld I have been doing my homework

 

[jonesg]

Re: Has anyone built/upgraded their compressor DIY style?

I recently snagged a 220v 21 gal vertical tank compressor from harbour freight, paid $120 with a coupon on new yrs day. They're LOUD though.
Works good for my plasma cutter, not enough for the die grinder.

 

[j_martin]

Re: Has anyone built/upgraded their compressor DIY style?

The 5 hp is B as in B, and S as in S.
1 HP in electricity is 746 watts. 5 would be 3730 watts, which would be 34 amps at 100% power factor, or 42 amps at a more realistic 80% power factor. That would be with no losses. More realistically, a motor that draws 20 amps at 110 volts is about 2 HP.

I used to have a commercial 3 HP, 2 stage compressor that ran 12 CFM at 175 psi. It drew 15 amps at 220V. It would run a couple of air wrenches and a zip gun chisel all day.

If you need volume cheap, get a few of the little pancake compressors and manifold them together. If you can afford a real air compressor, just go buy it. If you need high pressure (over 110 lbs) then you need to get a 2 stage compressor.

I was working on a remote building site (Way North in MN, 20 miles off the grid) and they tried to run a compressor about like yours off a generator. The generator wouldn't start it. I took inventory, and the volunteers had 3 of those pancake compressors. I went to town and got a handful of fittings, and rigged them up in a gang. Started one at a time, set at slightly different pressures. Started right up and kept them all in air for 3 days.

my 02
John