Midway Spiral Gear Blower

[DavidManuel]

So I took the advice of the forums and let my and my wife's family know about my obsession hobby. This is the gem my wife's great uncle found at a trade sale for $25 dollars. (Was mounted to stand, not included in picture.)

                

The seller stated that they had bought it for decoration as it was locked and wouldn't turn.

So I began research. I found many results on Champion 400 blowers and gear boxes, but few on my specific model. A couple videos and 2-3 hours of research later, I felt less like a monkey with a wrench. I was a gorilla with a soft hammer!

Now unfortunately my phones camera was being interesting at that time, so no in process photos were taken. But I had decided to move forward slowly and methodically. Fan shroud disassembled easily enough. The retaining nuts broke over with little force, so the fan shroud and fan were off. Then the fun part began.  

The lid to the gear box was off with two screws and no hassle. It was then I noted that the key pin to the crank gear had caught the housing and took a small chunk out of the gear hub. I saw no spider webbing so decided to combat that issue when I get there. I generously coated the sleeves and remaining housing bolts with thread oil and pondered the rest of the process as I waited. I reasoned that the main handle gear should slide out following the removal of the square bolt in the cog and retaining key removal. This led to the first, of remarkably few, mistakes. I  mustered the courage and removed the middle sleeve from the gear box. Little twisting and yanking and it was a done deal. This emboldened me to take the same approach to the upper gear sleeve. I covered the sleeve with the cloth and started to twist on it. The vise grip gave a lurch and fell off. I noted that now the neck of the sleeve and a ~3cmx2cm chunk was missing from the housing! Oy vey.

(Note that this pic is after the cleaning and placement of quik steel epoxy putty.)

 

I abandoned this frustrating side and went to the rear. The sleeve here was flush against the housing. Et tu sleeve? Long tale short, I ended up breaking off the remainder of the key pin and extracting the gear (shaft/axle?) and gear itself. Thoroughly done with the last 1.5 hours on this gear, I turned to the precision bit. The lower bearing assembly.

The research I had completed led me to understand the bearing was more than likely a cup and ball bearing. Sure enough this was the case. Now looking back, I realized that I had a stroke of luck in removing the better of the two nuts. I was able to remove the rod and all the bearings following this one nut removal. Gear shaft out. I looked to the middle gearing. I admit that this one completely and utterly stumped me. I was more weary now to hammer away on the delicate material and noted that this assembly turned freely. I decided to err on the side of caution and leave it well enough alone. 

Now the fun, and dirty part. I opened all the windows and turned on the box fan to blow out, and began using liberal applications of brake cleaner to clean the gunk riddled gears and parts. I used my flat head screw driver to remove the majority of the large mud dobber residue, then hit all outer surfaces with the wire wheel on the old hand drill. Once it was relatively smooth and clean, I used a brake cleaner moistened hand towel to clean the dust/ particulates. I used a small metal bowl with a magnet on the bottom to contain the screws and bearings as I doused them in the cleaner. This is where my second mistake was made. In the midst of the chaos, 3 of my BB were lost. My hunt has not borne fruit, but I plan on using my magnet yard sweeper tomorrow to hunt again!

Now for the problem of the gouge in the housing. After some research, and some debate on learning to braze, I settled on the Quik Steel metal epoxy. I formed the putty into the divot, using the rod as a size guide, and so far am reasonably happy with the appearance. Whether it stand the test of work/time I will update as issues arise. 

I decided against leaving the traditional patina and decided to coat and seal with Rustoleum paint in red and black colors. I hung the parts from clothes hangers and applies as directed. Here are the results after a 6 hour dry.

I am happy with the outcome. Unfortunately I am unable to continue on the project at this time due to necessary work activity. However this leaves me in a nice position to show off my progress and ask for input/ answers. 

So IFI I request your expertise on these questions, if I may be so honored.

1. If I don't find the errant BB, What is my recourse in this situation. Do I need to size and match according to any MH standard or similar? Or do I just throw BB in and call it good?

2. Following the advise of other posts, I decided on using ATF for my lubrication of choice. I live in southern Oklahoma, so the seasons are temperamental at best, and didn't want a cold snap to turn any heavier oil to honey in nature. Is there a better choice at this time. Thoughts on Lucas full synthetic? I believe Frosty mentioned its use at one point. 

3.Ant tips on reassembly would be appreciated. 

Thanks for reading!

 

[Latticino]

Well, I'll be following this as I just got a similar blower (though I paid almost 5 times as much I still think I got a deal, so you surely did).  Mine has a Champion blower casing and a Midway Spiral Gear gearbox.  Perhaps it was cobbled together by someone else, but it still seems to turn OK and blow air, so all to the good.  I don't think I'll be going for disassembly, like you are, but just cleaning out the gearbox and refilling with oil.  I'll also need to rig up some kind of stand and decide whether to mount directly on the coal forge or make an independent stand.  Thanks for posting the photos, those will certainly help.

[DavidManuel]

I'll post final assembly and stand as they are finished. If it had not been in need of repair then I would have done same as you. 

Also mine is the same with the Champion blower and Midway gearbox, but Midway commissioned maybe?

[DavidManuel]

Here's the finished pictures. Still thinking about the pole. Trying to convince my self to paint it instead of just wiring it off and clear coating the surface. 

Just a few questions;

1. When I turn the handle and release, the handle travels 1/4 to 1/3 a rotation and stops. Is this typical?

2. It has a good whirring and wiring sound. But feels like the spiral gear is grinding a bit. I'm using ATF for the lubricant. Should I use/add something more viscous?

Been a real treat working on this beauty. Learned a lot about working and respecting older parts, and Cast Iron

n.  

 

[ThomasPowers]

My favorite large blower travels 3 full turns after I release the handle. I've seen blowers that stop dead---too much work for me. I don't have that particular model and so can't speak about it.  Is it easy to turn?

[Marc1]

Mine keeps on turning for almost a full turn, depending how hard you turn of course. The inertia of the whole assembly is what makes it continue turning, especially the fan. If the fan does not turn freely it makes it heavy to turn fast and stop as soon as you stop turning. 

How is the fan bush? How do you lubricate it? Are the gear immersed in oil or just oiled from time to  time? An oil bath would stop the gears quick smart too. 

[DavidManuel]

 

Turns easy enough to my amateur arm. I recorded this video to see if anyone with a better ear could hear something I couldn't. 

Using Automatic Transmission Fluid for the  lube. I made sure the fan was off the shroud wall. 

 

[Marc1]

The fan is touching somewhere. Are the gears in an oil bath?

[DavidManuel]

1 hour ago, Marc1 said:

The fan is touching somewhere. Are the gears in an oil bath?

Not a bath per-se. Put about a half pint or so. Will double check fan when I get home. 

[Latticino]

Definitely hear more grinding than mine, and I haven't even cleaned and lubed it yet.  I would certainly check the fan.

[Marc1]

When you check it, check if it is centred. Make a fixed point with a wire wrapped around one of the screws and bent close to the edge of the fan and turn slowly. 

I prefer to use chainsaw chain oil because it sticks more, but wouldn't help to keep the thing turning more freely. 

[Irondragon Forge ClayWorks]

Transmission fluid is a little too thin, a better lube is chainsaw bar oil with a little STP or similar added.  It does sound like one or more fan blades are dragging on the case, but it could also be gear "chatter" due to light or not enough lube.

[DavidManuel]

So finally got round to messing with it again. The balls in the bearings were a little on the rough side. So I followed up on a hunch and it paid off. The ball bearings in the blower are just  about the size of a traditional BB. After I seated the cup and used some bar and chain oil to lubricate, the blower gives a turn and a half from full blow. 

Thanks all for the helpful tips. Now to find a way to revamp the pedestal.

[jlpservicesinc]

Just a note:  These old blowers with loose ball bearings the tension for the bearings is usually pretty low.. Somewhere about finger tight.. 

That is a mighty nice blower.. It will offer another 3 or 6 lifetimes of use..   I'm used to be a big fan of conventional oils as that is all they had in the old days.. 

I recently (10 years ago) moved over Mobil SHC and find it works very well in all the blowers and especially worm drives like the Champion 400 and is safe with brass and bronze which a lot of gear oils and regular oils are not.. the high pressure additives are designed for shear loads vs face to face loads..