Who is doing Blueprinting? Clutch Bell Turning

Dave Thacker /

I haven't noticed anybody offering blueprinting services. I've ordered the materials to to build tooling for Tomos clutch bell turning. I've decided I'm going to chase down vibration to entertain myself. I've noticed on the machine I have down for clutches now the bell varies in thickness about .012". The inside surfaces being machined, it should vibrate less with the outside surfaces concentric to the inside. (edited)

Re: Who is doing Blueprinting? Clutch Bell Turning

I've found that you can come close by taking away material, drilling holes on the heavy thicker side, I have a 1/2 drill that I spin the clutch on and look for that inner edge to hold steady at speed. Its pretty much trial and error thing with washers taped on, sharpie marks all over and your clutch bell looking like swiss cheese. Kinda feel better doing this way instead of thinning out the outter bell. Of course your clutches should be balanced as well. Makes a world of difference vibration wise, plus all that wasted energy going into your wheels instead of shaking.

Re: Who is doing Blueprinting? Clutch Bell Turning

Dave Thacker /

I got the 3MT blank arbors today. It's a way of making a repeatable on center fixture in my lathe. I'll be turning the stub down for a precise fit inside clutch bell roller bearing bore. Bolt down the middle to secure it all. Everything should be turned off the roller bearing bore. Will true up the outside. I realize this isn't balancing, but I'm moving in that direction. I have a very sensitive Hi-Point balance fully capable balancing a 6mm nut. I could fit the clutch bell on it and take it further if I wanted. For now, I just want to get rid of the extra metal that is not concentric with the bore. Trying to get rid of the strong vibration at speedo 35mph. Very curious if this will make a difference or if the vibration is crank related.

Re: Who is doing Blueprinting? Clutch Bell Turning

That's awesome! The thing about the clutch bells is that when the clutch is expanded into it, it takes up the bearing clearance and becomes a complete system, I'm sure you realize that, the clutch is way more important in the whole thing. Some tomos bells are just welded way off.

Re: Who is doing Blueprinting? Clutch Bell Turning

Dave Thacker /

I realize it all becomes one locked up unit. The space between the shoe an bell is taken up. No bearings or bearing bores change. I've built and blueprinted racing kart engines. ALL vibration is horsepower lost. It takes energy to shake or vibrate something. I will be making the tool this weekend to turn bells on the lathe and machine away the out of center material on the outside of the clutch bell. This will reduce a source of vibration. Detailed balance of the bell and shoes would reduce it further. One side of the bell is thicker by .010. Which means it is heavier on that side. The first step is removing that material. Removing it in a precision way.

Re: Who is doing Blueprinting? Clutch Bell Turning

Ϫ‡☄ಬ∞ ƀƖḬƝƊ ƤǂƿƎ ∞ಬ☄‡Ϫ - Hoke from Black Pipes Moped Gang /

good stuff here, keep us informed

Re: Who is doing Blueprinting? Clutch Bell Turning

Dave Thacker /

Just so nobody in this thread thinks I'm a kidder.

20200627_165520.jpg

Re: Who is doing Blueprinting? Clutch Bell Turning

roy jongejan /

so... why not balance the whole crankshaft assembly?

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