Board index Flathead Power-Technical Questions, Answers, and Suggestions 45 Flatties Good quality engine sprocket source?

Good quality engine sprocket source?

Post Thu Sep 01, 2011 8:04 pm

Posts: 36
What is a good place to buy a 33T engine sprocket that is not junk?
I just waited weeks for an aftermarket repop to arrive from the USA, and the tapered hole in the middle is roughly turned on a lathe, not ground/lapped like the original - and the taper is totally wrong. A .030" difference in size of the hole at the large end on the original and the repop, which only goes on to the shaft halfway and flops about loose.
I will send it back to the supplier but really not interested in exchanging it for more junk from the same sloppy manufacturer.
Any suggestions?

Post Thu Sep 01, 2011 8:41 pm

Posts: 53
Which company was it from so i don't waste time and money . I always had success from 45 restoration myself.

Post Thu Sep 01, 2011 9:01 pm

Posts: 36
flathead1943 wrote:
Which company was it from so i don't waste time and money . I always had success from 45 restoration myself.


Well, I don't want to name them at this stage because this might be a one-off defective part that slipped through, and I have not contacted them yet.

Have you bought engine sprockets from 45 Restoroation before?
Were the tapers ground/lapped to a near-mirror finish like the originals, and not just rough turned on a lathe like the one I got?

Post Thu Sep 01, 2011 9:25 pm

Posts: 426
Location: Tucson Arizona

Just so you know, there's supposed to be a 1 degree interference difference between the shaft taper and the sprocket taper so as the nut is tightened it bites into the shaft.

I've sold probably close to a 1000 sprockets over the years and no one has complained about fitment before.

AFAIK.....I believe most sprockets come from the same manufacturer......there are a couple who make odd sizes though. How many teeth does yours have?

Kurt
Last edited by Kurt on Thu Sep 01, 2011 9:33 pm, edited 1 time in total.

Post Thu Sep 01, 2011 9:28 pm

Posts: 53
Can't say i have ordered any to be honest i mostly got carb,electrical,clutch stuff.Have you look at ebay under NOS WL/WLA/WLC, sometimes there are gems in there. I found that looking at the seller other items for sale bring cool stuff too . Frank

Post Thu Sep 01, 2011 9:37 pm

Posts: 53
http://cgi.ebay.com/ebaymotors/33-Tooth ... 20b7daaf4f

Got stuff from them before with no problem fast shipping hope this help

Post Fri Sep 02, 2011 6:12 am

Posts: 72
Location: South Australia
Hey Pete , most of the gear I have used over the last few years have come from 45 parts or NOS parts, both have good quality and service,Just can't wait for Kurt to reopen, soon I hope.
I have a 33 tooth on my and find it to high for around town, runs better with 31 tooth and still cruise the open road at 100kph.
" The more I learn the less I know"

Post Fri Sep 02, 2011 7:06 am

Posts: 304
Location: Jonesville, Louisiana, USA
I've ordered both a 33T and a 34T sprocket from Kick-Start M/C Parts (and a host of other NOS and aftermarket parts). I have been totally satisfied with them.

Post Sat Sep 03, 2011 1:14 am

Posts: 36
Thanks for the info, guys. Yes it is a 33T sprocket, and way more than one degree difference in taper. I guess will send it back and try again.

Post Sat Sep 03, 2011 4:54 am

Posts: 36
LOL - just checked and Australia Post wants $47US to ship that $35 sprocket back to the US, including a $10 "security surcharge" on packages weighing over a pound. Waiting to hear what the supplier says he can do for me.

Post Sat Sep 03, 2011 9:14 am
Pa Site Admin

Posts: 5837
Location: Ohio USA

Hopper....try Tony Blain at redfern motorparts in OZ. His email addy is redfernmotorparts@bigpond.com . I believe he is in the US for the Davenport swapmeet so you may wish to try him in about a week. Tony may have an nos one on hand. Pa

Post Tue Sep 20, 2011 3:24 pm

Posts: 199
Location: Cedar Springs Mi USA

"Just so you know, there's supposed to be a 1 degree interference difference between the shaft taper and the sprocket taper so as the nut is tightened it bites into the shaft."

Kurt, I don't know where you got that information, but in my opinion, ans a parts manufacturer and tool and die machinist in the auto industry for over 35 years, I can tell you, according to SAE standards "locking taper" fits have to match within 5 minutes of one degree.

One degree off to make it "bite into the shaft" is a excuse from someone that can't make a part right.

Post Tue Sep 20, 2011 3:34 pm
Pa Site Admin

Posts: 5837
Location: Ohio USA

I worked with tapers for many years, matching male mating female sets mostly. The pair wre not correct until we lapped both tapers together 100 %. At 100 % and fatener tension applied, the two tapers become parent metal [one piece].

Post Wed Sep 21, 2011 6:55 pm
jib

Posts: 575
Location: devon,england
pa ,doesnt that depend on the actual angle of the taper? like a 'morse' taper used on drills lathes ,mills etc ,the male and female are virtually the same ,however thier taper angle is not such,that they cannot be seperated. 37.5 degrees comes to mind???
and remember 'ringing' two flat measurment gauges together , they cannot be pulled apart ,yet if twisted 90degress will fall apart
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years

Post Wed Sep 21, 2011 8:50 pm

Posts: 36
Pa,
This is what has me concerned about some of these aftermarket sprockets - the taper appears to be merely a lathe-turned finish, not ground, not lapped. I haven't received my replacement sprocket yet so not sure if they are all like that. But the pics of the new-style turned-from-billet sprockets all look like a dull turned finish in the hole.
The old NOS style sprockets made from a forging or casting all have a mirror finish on the tapered hole.

Post Wed Sep 21, 2011 10:00 pm
Pa Site Admin

Posts: 5837
Location: Ohio USA

jib wrote:
pa ,doesnt that depend on the actual angle of the taper? like a 'morse' taper used on drills lathes ,mills etc ,the male and female are virtually the same ,however thier taper angle is not such,that they cannot be seperated. 37.5 degrees comes to mind???
and remember 'ringing' two flat measurment gauges together , they cannot be pulled apart ,yet if twisted 90degress will fall apart


It depends on the application. Does one wish a parent metal bond or and easily removed fitment.

Post Wed Sep 21, 2011 10:22 pm
Pa Site Admin

Posts: 5837
Location: Ohio USA

Hopper wrote:
Pa,
This is what has me concerned about some of these aftermarket sprockets - the taper appears to be merely a lathe-turned finish, not ground, not lapped. I haven't received my replacement sprocket yet so not sure if they are all like that. But the pics of the new-style turned-from-billet sprockets all look like a dull turned finish in the hole.
The old NOS style sprockets made from a forging or casting all have a mirror finish on the tapered hole.


Again we are looking at application. In an engine sprocket we need a good solid connection to the shaft. Tool marks, such as lather turned marks will quickly loosen up as the tool marks are crushed via the load. As far as the finish on nos tapers go, the mirror look was caused from the process and tooling in which they used to gain a solid taper to taper fit. Lapping creates a dull gray, but smooth finish. The whole purpose of grinding or lapping in tapers is to obtain a metal to metal fit all over. Mating tapers cannot hold true center with each other if the contact surface between the two tapers is tight at one end and loose at the other. They will wobble. In regards to tooling, such as morse tapers, the male and female tapers give to comform to a metal to metal fit as they are joined together. Only the felmale gives if the male is solid. The tapers are what really holds the tooling together, not the tang as you find on tapered tooling sleeves and drills. The tang is only for an additional insurance against spinning one taper within the other taper, while under load. In other words, the tang on such tooling represents the nut and lock washer on engine sprocket, pinion, and crankpin shafts. Keys are used as a drive but more so as a stop to prevent taper to taper spin. On a 45 engine, the pinion gear shaft uses no key where it is attached to the flywheel. Only the tapers keep the two parts together. But...the nut and lock washer keep the tapers from loosening and spinning.

Post Thu Sep 29, 2011 1:28 am

Posts: 36
Well, got my replacement sprocket today. Identical to the first one. Defective taper and all. Doh!
I measured up and calculated out the taper on the original factory sprocket is as near as dammit to 13 degrees.
Both the aftermarket replacements work out at 9 degrees. Just totally wrong.

So in the meantime I bought one from one of the suppliers someone mentioned above.
You guessed it: same wrong taper as the other two duds.

Must all come from the same bamboo shack.
I'm frightened to try any more as it costs more than the sprocket price to mail it back to the US.

Maybe I'll just mount a Dremel up in the lathe and grind the right goddamn taper on one of these duds. Trouble is I have a few health issues so just taking the primary cover and sprocket off the bike takes me several days, so don't fancy my chances of making a Dremel rig for the lathe right now. Talk about frustrating, sheeit!

Post Thu Sep 29, 2011 8:06 am

Posts: 641
Location: Wisconsin, USA
You should be able to cut the taper with a carbide bit in your lathe if you can find a way chuck the sprocket properly. On the subject of tapers, I saw some info stating that flywheel pin shaft tapers were designed for slight mismatch to facilitate the truing process. I was looking for the info to back that up but couldn't find it so I thought i'd throw it out there anyway.

Post Thu Sep 29, 2011 8:15 am
Pa Site Admin

Posts: 5837
Location: Ohio USA

I agree with being able to cut the taper.... but.... only if the smaller end needs cut. If the larger end needs cut, the gear will sink onto the shaft to far and miss align other components.

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