I have a Bosch DU-4 magneto being driven off of a Bosch triple gear unit on my '14 speedster.
I'm posting from my phone so I can't upload pics right now, but here's an accessory of the day thread with the exact same item I have. http://www.mtfca.com/discus/messages/331880/370388.html?1381924692
The center gear on mine the teeth are worn almost to points, they look more like a bike sprocket than gear teeth. Also, there is a bronze bushing in the center of the gear. That bushing is worn and is letting the center gear move around a lot. I think a better fitting bushing to the post it rides on will help reduce the wear a lot.
Is there anybody on here (or someone you might know) who could machine me a new center gear and bushing? I could mail gear and even the post it rides on for reference, as well as the larger gear so that the tooth sizes could be matched up. I've taken some pics and will post them on here tomorrow. Just PM or post on this thread.
I'm almost done with my valve job (new stainless valve and fresh cut seats, plus new Stipe 280 cam). I noticed the play in the gears when I was disassembling things for the new valves and cam. I figured I might as well work on fixing this while the car is out of commission and before it becomes a problem.
Sorry, wrong accessory of the day thread! Lol, here's the right one. http://www.mtfca.com/discus/messages/331880/371536.html?1373403034
See what Boston Gear has in their stock gear catalog. You should be able to match the pitch from pictures in the catalog. Teeth will most likely be 14-1/2 degree pressure angle. I suspect you can modify one of their stock gears to fit.
Here are some pics. From what I can tell it looks like outside diameter of gear is 2-5/8", and diameter of bushing is 3/4". There are 30 teeth. The last picture is of the largest gear and essentially what the teeth should look like on the center gear.
dan mceachern most likely makes those gears. get him at firstname.lastname@example.org high quality stuff every time
Here's your gear,12 DP,30T. machine to correct thickness and add your bronze bushing.
Boston Gear 12 DP.pdf (83.6 k)
Thank you for the responses and help! Hey Ted - I went and checked out the Boston Gear website and for the most part felt like I was trying to read Chinese. =) How do you know/how can you tell it's 12 DP? I'm not saying you're wrong just want to get educated on this.
Clayton - I sent Dan and email and will see what he says.
I may give BG a call after work today and see what they say - explaining that I have no idea what I'm talking about. I don't have the tools or access to a machine shop to bore out the gear or the bushing like I need, and there's really nobody local willing to fool with it. All of the little projects I've brought in to the couple of local places either say they don't have time for or "Yeah, I can work it in sometime in the next 2-3 weeks for $500". Quick tangent - what really sucks is I work at one of the largest and most capable aviation re-work facilities in the US and the guys here would be more than happy to make me ANYthing I want for my T - except that it's all government property and home projects are highly frowned upon. The machine shop area here is literally the size of a Walmart with jig-bores and multi-axis computerized milling machines and you-name-it out the wazoo, plus a TON or artisans with decades of experience.
Anyway! I can get my hands on a mic and put out some good measurements for someone else though if someone is willing/able to fool with my little gear requirement. If the price is right I'll even buy two so I have a spare.
Well, apparently I can't type or proof-read today. Sorry for all the errors.
The number of teeth is 30, the pitch diameter is 2.500" and the OD is 2.567. I think this matches your dimensions.
I know the picture doesn't show it very well because of the perspective, but OD (from outside edge of tooth to opposite outside edge of tooth) is exactly 2-5/8" or 2.625" I don't know if that changes the DP or not.
I've called Boston Gear but so far I'm on infinity hold waiting for tech support to help me figure out exactly what part # I need and how it needs to be modified if at all.
You probably have a local distributor (a good bearing supply house) that should be able to help you as you stand at the counter. They will not likely have it on their shelf, but should be able to get it for you quickly. Hub modifications can be handled easily by any decent machinest.
I will highly recommend that you replace all the gears that mesh together at the same time. Replacing only one is false economy!!
OOPS! The OD is 2.667, seems I can't add sometimes.
Howdy Les - I called a few places and ended up being recommended to call Gear Makers Inc in Pennsylvania. They were super nice and just want me to send them the gear drive part of the unit I have and they'll give me a quote. I'm going to get 3 prices - one for just the center gear as it's really the only one with wear (in case it's super expensive for options 2 and 3), one for a whole new set of gears, and one for a new set of helical gears (right now the gear drive is really noisy, these might be way quieter). And then, depending on how realistic the price(s) are, I'll pick one of those options. I have nothing to go off of, but I'm hoping I can get at least a new set of all 3 for less than $250. That may be unrealistic, I don't know.
McMaster Carr has a 12 DP 30T gear in stock:
Your other gears are going to be harder to come by, the smaller is 23 teeth and larger, 46T.
We will see how much it costs, but I'm hoping Gearmakers is going to be the answer for me.
To find the DP of a gear; count the teeth add 2 divide that sum by the diameter of the gear and round off the number ---- 30 + 2 divided by 2.567 = 12.46 rounded to 12.
Please tell us how you make out
Will do Les. We are snowed out in North Carolina today, so I won't be able to ship my pieces out until tomorrow or Thursday. Probably be next week before I hear anything one way or the other.
Just email Dan McEachern, ask him to make you a set and send them to you. You will be happy with the quality and the price, I think the last set of gears he made for me he sent the gears and the invoice. He is a Gentleman and a quality machinist. Just my .02 worth. Bill
Danís Antique Auto & Machine
920 Pearl Street
Alameda, CA 94501
Danís Antique Auto & Machine
Engine Rebuilding, Rebabbitting & Machine Shop Service.
Complete Stock of Model T Engine Parts and Speed Equipment.
Dan emailed me and said he isn't making these right now - he can't just whip some up for me. If I don't get what I need from these other guys to contact him and he will see what it will take to make them.
Sorry for bumping up such an old thread but just wanted to give everyone an update: I sent all of my stuff to Gearmakers Inc up in Souderton, PA, and they are working on it for me. I got a quote of 3-4 weeks. Well, 4 weeks was last week on Wednesday, and the guy up there tells me today he thinks it'll be done by the end of the week but only after I've called him. Don't waste your time or money with them. I don't care if what I get back is amazing. A 50% refund of the $815 I spent UP FRONT with a sincere apology is about the only thing that might make me not tell everyone about their crappy business. They're terrible at email communication and the only way I've accomplished anything has been on the phone. Wish I had found someone else to help me with this.
$815 - ouch! Maybe you're throwing good money after bad into your magneto drive?
I think it would be possible to find another complete working magneto drive with good gears for much less?
I've got about $50 in mine, $40 of that in the quality bicycle chain
Let's see how good it holds up..
Nice job on the mag mount Roger, here is an original chain drive Bosch mount.
There was about 7 complete Bosch front drive units for sale at the Bakersfield meet this year. When it rains it pours I guess.
I have asked folks to look for me a mag drive unit and I never got any bites. One guy on here had a chain drive mount but for about the same price I'm getting these gears done. I figure if nothing else they should last a long time. I have a pre-generator block but am running an alternator up where a chain drive magneto would go. Anyway, just wanted y'all to know not to do business with these fools.
Get this from Boston >>> http://engr.bd.psu.edu/rxm61/MET210/CourseSupplements/Manufacturers%20Data/Bosto n_Gear_-_Spur_Gears.pdf
Scroll to 12 pitch CHANGE GEARS.
See if you can find what you need there and if you do contact a Motion Industries branch in your area >>> https://www.motionindustries.com/motion3/jsp/mii/miLocations.jsp?LANGUAGE=0