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SmithingWitch

Champion 400 blower gear measurments

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Hi folks! about a year ago i posted about a recently acquired champion 400 blower i got thats got all the parts in great shape...minus the bronze gear which has been worn so hard the teeth are like razor blades. At the time there wasn't much i could do as the gear was well and truly stuck to the shaft and i couldn't get it out of the housing to try and do anything to it and there it stayed as I was living in las vegas and the blower was on my parents farm in North Carolina. Ive since moved back east and due to the current state of the world have had plenty of time to work on my projects backlog, and finally through soaking in cleaning vinegar, heating the xxxxxxxx out of it, and liberal applications of ATFcitone and a bit of nervous tapping ive managed to get the little cuss out. 

I was told earlier by a local older machinist theres not anything that could be done on his equipment given the helical nature of the teeth of this gear, which leaves me with two options short of finding another parts blower with a good gear, which given the aforementioned state of the world it doesn't seem like many swap meets etc are coming in the near future.

One option is model the gear or the necessary characteristics of it, and have it CNC cut out of bronze. this will likely be more of a hassle and more expensive but may make a longer lasting gear in general. 

Option two, and one i think has potential from a diy sense that can be done in-house, is again model the gear but instead of sending it off to be CNC'ed, print it on a 3d printer using a fiber reinforced filament and 100% infill. while i cant see it lasting quite as long as a bronze gear, other blowers have gears of phenolic/micarta materials that continue to run well, and there are videos of 3d printed gears replacing metal ones on machines such as lathes and even engines, when printed using the right filament. While it wouldn't be as strong as bronze, once the code for the gear was created all it would take would be to hit a couple buttons and wait a day for a new one to print for a very low cost in materials, so a new one could easily be made when the old begins to wear out, and be printed by anyone with a suitable 3d printer. As a side benefit it would be much quieter running using a reinforced plastic gear vs an all metal drive, and the part I really like: If made, the file code for the gear could be made available to others with a broken or worn bronze gear as thats whats keeping many of these 400's out of commission, short of ones folks have tested gravity with and shattered the casing etc. 

Heres the issue though. My gear basically has just enough tooth to tell it isn't a smooth wheel, and as i've never done this sort of thing before I really don't trust myself to pull accurate measurements off of mine. with the proper measurements i could plug it into a simple program and create the tooth profile then just fiddle around to make it dimensionally the right size on the shank etc. 

Does anyone who has a champ 400 with a non-torn up bronze gear happen to know these measurements or know how to get them/would be able to get them off their gear? 
The measurements Id need are:

Pitch Diameter

Diametrical Pitch
Pitch Angle 
as it is i count 86 teeth but if feel free to correct my math as i can restore things extremely well but when it comes to fabricating of this nature i'm a total novice and am basically operating under the assumption i'm doing something wrong unless told otherwise. 

 

If anyone could help me with this dilemma id be extremely grateful and I truly think it'd be a boon not just for myself but for others looking to maybe save one of these machines from the junkyard.


(And before anyone asks why not get another blower, i've got a lot of very good memories using a champion 400, this one i own was a very good price despite the gear and i'm maybe a little overly emotionally invested at this point, but I absolutely prefer using a manual blower to an electric because it gives a tactile feedback to the fire much more than flipping a switch ever could)

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I'd find another blower and use the one you have for parts or the one you find for parts. Having one 3D printed would probably work though I'd have it printed in wax, make a mold, cast it in bronze and hand finish it to serve penance for doing it the hard way. 

Have you priced phenolic and the kind of fiber you'd need? Forces aren't the issue it's wear on the other gears and solubility in lubricants that are the issues that come to my mind. 

Heck, I've been keeping my eyes open for a new champ 400, my old one is maybe done for. I brought it to a hammer in summer before last. The blower started to catch on something like maybe a pebble or piece of broken gear and one of the guys using it just cranked harder rather than trying to find out the problem. Slammed it harder ad harder till it was locked solid. THEN said something. :angry:

So, anyway. . . I'm going to buy one to replace it or for donor parts.

Dat's my two bits.

Frosty The Lucky.

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i can get a roll of carbon fiber reinforced nylon filament for around $50 usd and would maybe use 1/3rd of that volume for the gear. as long as youre not using anything that would eat nylon as a lubricant I dont see that as being an issue, and likewise doubt it would be capable of noticeable wear to the worm drive which is the only other part this gear interacts with aside from the shaft its mounted on. Ive repaired sewing machines as a hobby for years and have seen numerous cases of a nylon gear contacting a worm drive similarly to the arrangement in this blower and short of some freak cases of extenuating circumstance the steel gear shows no visible signs of wear. the upside of nylon is its got a little flex in it so it would move out of the way rather than cut into the other parts

That said, if anyone has a working bronze gear from an otherwise broken machine they want to be rid of, by all means let me know as that by far would be the easiest option but would still like to try going with a printed one just because if it works it would mean a lot more than just my machine being fixed. 

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