Air compressor (re)build

[pdg]

After being innundated with literally one request for a thread on my compressor, I thought it best I get on with it...

Many years ago (I think it was about 11 years back now, but I might be out by a few) I got a compressor. While it ran, it wasn't exactly happy. There was no valve or pressure release so the motor had to start against pressure, the pressure switch had very burnt contacts (high start load I assume) and was physically damaged, so I thought I'd give it a good going over.

Firstly, because it felt 'crunchy', I stripped the motor and found that the centrifugal contactor (to disconnect the start capacitor once up to speed) was also extremely burnt and also that the armature had a lot of bad scoring/damage from crap drawn in through the fan. The bearings had also seen much better days so feeling a little disheartened I decided to leave it for a while and come back to it later.

Well, now it's later.

Slightly less many years ago I got another compressor for some parts - the previous owner neglected to put any oil in the pump head and it munched the crank... He kept the motor, but it gave me a load of usefull parts (decent pressure switch, a bigger receiver, an aftercooler, good non-return valve, etc.) so it was worth the trip.

As a thread is worthless without pics, here are a few that I took a couple of years ago.

From the first compressor.

The pump unit, manufactured by Sherry:
https://i.imgur.com/bgkLdar.jpg

Data plate from the receiver, showing a 1959 build date:
https://i.imgur.com/jRtrPLg.jpg

And from the second one - a Dunlop ST5:

The receiver data plate, showing a 1947 build date:
https://i.imgur.com/6y8t9WQ.jpg

A pretty good quality and eminently serviceable pressure switch:
https://i.imgur.com/SbCVVq4.jpg

At this point, I shall continue in another post to break it up a little.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[pdg]

Continued....

The plan with this compressor is in 2 stages - stage 1 is to make it work by 'borrowing' the motor from the lathe because I have a sensible drive pulley that handily fits (well, the keyway needs expanding, but I have a file or two):

https://i.imgur.com/XWy3Px0.jpg

Stage 2 is when the lathe is up and running to fit a petrol engine instead - but that is later. I'll probably keep the thread running through this if there's any interest at all.

This evening I made a (-nother) start on it. Starting off with the pump unit.

Because I'm so thoughtfull, I left the pump outside in the garden for about a year or so.... As is probably to be expected the crankcase filled up with water, I drained it out and took off the side cover:

https://i.imgur.com/WBz3p64.jpg

Yes, it looks horrible and rusty. But:

https://i.imgur.com/ECgzenX.jpg

That's after a quick wipe off with a bit of rag. What appears to be rust is remnants of emulsified oil. It's really in very good shape.

I took the head off too:

https://i.imgur.com/ImKolax.jpg

The piston crowns have some stamping:

https://i.imgur.com/3kp7u69.jpg

Now, whether that's a date or not I don't know. If it is (and assuming the pump is the same 1959 vintage as the receiver) the pistons have been replaced. I'm not bothered either way really - the pistons move nicely in the smooth bores and seal against air. Considering it hasn't been spun for quite a few years and the bores are dry, that's a good sign.

The pump is currently completely stripped and ready for clean and paint - probably tomorrow or so and then I'll get it back together and nicely lubed ready to move on to the next bit.

To be continued again.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[pdg]

This evening / tonight I stuck some wheels on the receiver and slapped on a bit of paint. I bought those wheels specifically for using on the compressor, about 8 or 9 years ago.........

https://i.imgur.com/4CAZZNw.jpg

Epic brush marks and stuff showing, mainly because it was still very wet when the picture was taken. It should flat itself out fairly well by tomorrow, but it'll probably need another coat.

I did do a bit of a 'test' on it by plugging the holes, filling it with water and pumping it up to about 200psi, then I pressure washed the inside (and got out some crap) before drying and painting it.

Oh, and I cleaned up the pump block a bit - the old oily/emulsion mess inside came out easily when warmed a bit, soon I have to mask it up and give that a bit of paint too.

I'm not being overly picky with the finish, just so long as it's clean and protected that's good enough.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[331X2]

Looking good, love the pump.

I've got a single cylinder pump of similar vintage on my dad's yard, thinking of dropping it on a 47kg propane cylinder with a 2hp motor as I've got one of those wank little 25l oil less hobby compressors at the minute and it's loud as fuck.

[pdg]

Tonight's job was to clean up the pump block with a selection of wire brushes and mask it up ready for paint.

https://i.imgur.com/YvGFraL.jpg

I used a high temperature paint - these pumps get pretty warm when they're running and the old paint was peeling quite badly from the cooling fins so a finish that can take the heat seemed a good plan. The only 'thing' with this paint is it needs curing....

So, spray the paint on then pop it in the oven after it's touch-dry. Then set to lots of degrees (gas mark hot) and bake for a while or so. Best to put the item in with the oven cold and let it come up to heat evenly.

https://i.imgur.com/8iuPGgS.jpg

I'll take it out tomorrow, cast iron doesn't cool down all that quickly.

So, while that was cooking nicely I got the pulley to fit on the motor. The shaft was the right size but the key on the motor was too wide for the slot in the pulley. Make the slot a bit wider and:

https://i.imgur.com/lHrryYK.jpg

https://i.imgur.com/ISUQAcV.jpg

Now it fits.

All the covers and the head from the pump need prepping and painting, then I should be good to put the pump back together.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[pdg]

[331X2]

If it goes in the shed it'll be vertical, agree with you on that I'd rather bung it in an insulated box outside though, will see at some point. Oil less one came in for a repair and never got picked back up, good for dragging down the drive but the noise makes me baulk.

No welding needed on the cylinder, all pressure connections go through the original threaded boss at the top, might be slightly restrictive but I'd rather not be blowing holes in it with my stick welder

[Pete.]

[331X2]

Good call! Mount the cylinder upside down and have a drain on the low point of the pipework then

[pdg]

[pdg]

Time for a little tiny Sunday update I think.

Earlier, I cleaned up some more parts of the pump (covers and head), slapped on some paint and popped them in the shed oven to bake.

https://i.imgur.com/swQqpYy.jpg

When I took it all apart, I didn't take a lot of notice of weight etc, so assumed the whole thing was cast iron. As it turns out the two rectangular cover plates are cast aluminium instead. Seeing as it's a bit of a bugger to get paint to stick to aluminium reliably I thought I wouldn't bother painting them. I think they look alright.

https://i.imgur.com/mtmKY12.jpg

Jumping ahead a little, I cleaned instead of replaced the UNC bolts that hold everything together - have a before and after comparison.

https://i.imgur.com/fzHJgk4.jpg

Now, the oiling system on this little machine is really quite ingenious. Usually, as in small stationary engines of similar vintage, I would expect to see splash oiling where there is a 'dipper' on the con rod cap that literally splashes oil about. In here, there is a split ring around the crankshaft, held captive by a special bolt. As the crank turns, the ring is turned through the oil and carries it up to a double cone affair, where it is centrifugally pushed into the outer roller bearings and also through a channel into the plain big ends. With that 'explanation' you might be able to see what I mean in these pictures:

https://i.imgur.com/OjeE4ZV.jpg

https://i.imgur.com/uvYAp09.jpg

Having got most of it back together I dropped on the head and put the side covers on lightly for this, just to see what it looks like:

https://i.imgur.com/fEIqR35.jpg

Getting there. There are still a few little bits to do on the pump, I have to make a new head gasket and rectangular side cover gaskets and get it bolted together. Before the final reassembly though I have to get it (at least roughly) mounted to decide which way the head is going to face, and also which way round the side panels are going - that way I can make sure the pipework from the head is going the right way and that I can easily reach the oil filler and dipstick. Oh, and there are cap bolts for the valves in the head to get cleaner too...

More later.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[pdg]

I've done a bit more messing around...

There's been a selection of bits and bobs sat about in various tubs and boxes for a number of years now, all patiently waiting for me to do something with them - well, I did something with them:

https://i.imgur.com/KPAVMdq.jpg

I have there a pair of outlets, one of which is direct from the tank and the other is regulated. Each outlet has it's own pressure gauge so I can see what the tank pressure is and also what the regulated output is set to.

While I was playing, it seemed only fitting to do a bit more plumbing:

https://i.imgur.com/tfUZclj.jpg

At that point, my crappy camera battery decided it was a bit chilly and died again... But, I did do more.

In fact, it's nearly ready to run up. Left to do is:

Make gaskets for the rectangular side panels.
Put oil in the pump.
Find/fix/fit an air filter.
Attach the motor (which means 'drilling' slots in the mount plate).
Wiring.

I really should fit a guard over the belts as well - I have one, so I'll have to make some brackets for it.

With any luck, that'll get done tomorrow evening/night - then it'll be time to plug it in and run away
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[pdg]

Right, so I think I mentioned that when I got the 'first' compressor it came with a motor. I also think I mentioned that the centrifugal switch system was a bit worn.

I found the wear when I took the motor apart shortly after I got it, which would be aroundabout 11 years ago.... I did intend to put it back together at the time, so I even painted the end covers.

Earlier on, I had a dig around and found all the bits of the motor. It turns out the wear wasn't as bad as I remembered, and with some sensible cleaning/filing/polishing it came good enough. The only thing I couldn't find was the wiring schematic that I'm quite sure I did at the time.

https://i.imgur.com/GExjtfQ.jpg

Well, as it happens (because I'm just that good) I figured out which winding was for what and wired it up - and it span around and everything. So I decided to use that instead of borrowing the one that came with the lathe.

https://i.imgur.com/aJXYmzz.jpg

The paint is looking like it's seen better days after being randomly shoved around for over a decade, but I did 'poverty chrome' the main motor body! To translate into English, I covered it aluminium tape (or, to put it another way, I wrapped it in sticky-back tinfoil). Still, it was quicker than paint and easier than trying to polish it.

So then I found an air filter - it's a proper compressor one which works like a silencer (it has a filter section and an expansion muffler bit) which 'should' quieten down the air-rush noise a little.

Wiring was next, what can I say? I put wires on it in various places...

So here's where it stands now:

https://i.imgur.com/azOIuZb.jpg

Getting there, there are a couple of little bits left to do - make those last 2 gaskets and put oil in the pump, and now an additional bit of replacing the oiler felts in the motor (but, if I remember to keep the plain bearings on the shaft oiled manually, I can do without those if needs be). Oh, and testing/adjusting (make sure it pressurises properly and that the pressure switch operates at a suitable pressure). I did slather some oil on the pump bearings and plug it in for a few seconds - it squashes air and shoves it in the tank!

I think I'm going to declare it done. So, unless there is any related discussion I will make one last post (probably tomorrow) just to say that it's lubed, adjusted and running as it should.

Now, take into account the fact that less than a week and a half ago this thing was a selection of parts from 2 completely different compressors which were scattered around the garden/shed/loft for an average of about 10 years - I reckon it's turned out reasonable.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[pdg]

Gaskets got made.

https://i.imgur.com/NPoTGiK.jpg

So I put them in, put the covers on and filled the pump sump.

Then, it was testing time.


Yes, the test failed............ Sort of.

I want to be able to use the compressor running off my generator, but the motor draws too much current at start-up with the pump connected to spin up. This could be the generator not having the oomph to do it (even though it really should) or there are age issues with the motor meaning it's not as efficient as it once was.

That being the case, there's not much point trying it on the mains, so it looks like another motor is the order of the day after all.

Still, gives me something to do this evening.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[Pete.]

[pdg]

[Pete.]

Rental gennies are very often 240V/110V. Check it's not putting out 110V
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[pdg]