Flywheel truing

[exeric]

My question is about Indian, or Harley flywheel truing. I have followed Tom Cotton's superb tutorial on how he does flywheels and I think it's some of the best advice I have seen. At this point I have lapped the shafts to the wheels and got a good matte pattern on all the tapers. I also indicated, and trued the pinion, and drive shafts to their wheels. With the shafts lapped, I put the assembly together. I put the assembly on the ways of my lathe and used a long 1/2 bolt to (hopefully) bring the wheels in line upon tightening the crank pin nuts. And, here's the problem; I always come up with high or low dial indicator readings at the crank pin section as reflected on the pinion, and drive shafts. I'm using a lead hammer, and I don't hit them hard. I've had some success with a hardwood wedge, and a C-clamp but it all goes back after the wedge, or clamp is removed. Is this indicative of a specific problem?

The wheels are in very good condition, with no cracks and tapers that looked good. All the shafts are new. I also indicated the seating face of the crankpin nuts to make sure they are perpendicular to the crankpin threads and they were good.

These are wheels for a 1941 Indian Sport Scout. I'm open to advice as I know there are some talented motor men here. . . . But that wouldn't be me. Thanks.

[exeric]

This forum doesn't like a Word document, or commas I wrote this in Word because I thought it might time out if I wrote it here. Sorry about the different font.

[T. Cotten]

Uh oh Eric,...

I did a tutorial? Beyond the lapping study (http://virtualindian.org/10techfly.htm), and editing a brief discussion at http://virtualindian.org/1techflywheel6.htm, you must please remind me..

Bringing the wheels in line on the lathe ways with a long bolt eludes me; There's infinite ways to skin a cat of course, but I could never do it fast and accurate without a press to hold the wheels, as described in the second link.

The assembly must be lugged back and forth from the press to the centers for progressive tightening and truing. But applying a pair of pry bars and a large C-clamp can often eliminate the need for a mallet. (I found with modern forged wheels, such as S&S and Evos, that the slightest shock would skew them from where you wanted them to go.)

Its all about careful observation, thoughtful application of pressure, and above all,.. patience.

....Cotten

[tfburke3]

I have had the same problem with wheels moving while tightening.
I made a clamp.Using about 8" long 3"x1 1/2" c channel. I machined both edges to about 30 degrees or so without moving the work so the faces are parallel the full length,then cut the channel in half and drilled a hole for a 5/8 threaded rod.
This aligns things surprising well and holds the wheels while tightening.

Tom

[exeric]

Its all about careful observation, thoughtful application of pressure, and above all,.. patience.

....Cotten

Patience, that's the clue! I'm trying Tom, but I don't do this for a living, and don't have your experience, and knowledge through many examples. In regards to tburke3's comment, my lathe bed is very accurate and similar to your application. I hoped that would get the wheels pretty close, and I guess it did, but as Cotten said, patience is the key, and finesse is what will get me home. Unfortunately, finesse isn't in my toolbox right now. Maybe Harbor Freight has it on sale right now. Believe me, I appreciate your comments and thanks for posting.

[T. Cotten]

I don't get it, Eric,...

The idea is to secure the wheels enough to tighten the pins, and that would be pretty rude to lathe ways.

My simple screw press (Toyota jack) could hold individual wheels or both, squared upon its parallel bed rails:

FLYJIG.JPG

Although it gave rudimentary alignment, all truing was performed between centers.

The press allowed the wheels to be quickly secured, released, and returned to the centers repeatedly, which is critical if you're going to make a living.

....Cotten
PS: A hydraulic press would have been folly.

[exeric]

I use the lathe bed to get the assembly somewhat aligned, and tight. I use a hydraulic press to hold them for final tightening. I know you can't give unequivocal advice on flywheels that aren't in your hands, so I appreciate your comments and experience. This is a job I do with years long gaps between the last one I did so I struggle, and get frustrated due to my inexperience. Again, the advice is appreciated.

[larry]

So a screw jack is superior to a pump jack?

[chuckthebeatertruck]

I'm confused by your description.

Are you placing the assembly between centers to measure run out or using the lathe bed? What type of indicator are you using and how is it mounted/oriented? Are you pulling those bolts out after initial assembly? Do you often use centers and are you able to set consistent tension? Are you centers well ground and the shafts also in blemish free condition?

Often, when folks don't do this but now and again, challenges can be induced by inconsistent measurements from loose or tight centers, nicks, or even mounting indicators at an acute or oblique angle. I've also helped a few folks whose indicators were old and stiff from disuse and dry lube in the clockworks. I mounted a starett last word for them and the wheels were done in minutes ;-)

Generally, on splaying, you need to move them much more than you think to get the correction to "stay" and more than once I've wedged wheels and tightened with the hard correction in place. No joke, the wheels spring back and that's where the experience comes back in.

Im always amazed at how a glancing soft blow can move wheels more than bashing on rims. It's an art. . .

[chuckthebeatertruck]

I use a hydraulic press as well, but two ground c channels top and bottom to hold the wheels square vs the bed. The trick is to apply only enough pressure to hold them against the torque. A screw jack makes it easier to feel that point. You can easily nick or dent wheels with a hydraulic press with one or two pumps.

A LOT of professionals will not use a hydraulic press. They use a holding tool in the vice or mounted to the bench. I've heard the arguements and I've done it both ways. I've not yet had an issue with wheels I've built, regardless of the method used to secure them for tightening.

[T. Cotten]

So a screw jack is superior to a pump jack?

In infinite ways, Larry!

There is no sense of touch with a hydraulic press, and you only want to hold the wheels so they won't move, which is less than a ton.

(Even my 60 ton screw press can be brought down firmly on your finger without risk.)

J&LPRES2.jpg

And screw presses are lightning fast by comparison, although I 'spose that's only important when you are working flat-rate.

....Cotten
PS: Yes Chuck! The press was only used to hold the wheels for tightening. It was then straightened between centers:

centers.jpg

[exeric]

I believe my centers are good as I aligned the tailstock, and actually machine a 60 degree center in the headstock so I know it's dead on. I use 1" travel indicators on magnetic bases but they are on angles to the flywheel shafts. I have 2 Last Word indicators so I'll give them a try. To clarify the lathe bed thing, I use the parallelism of the lathe ways to align the wheel assembly. I put a heavy plate on the bottom of the lathe casting and a long bolt through the wheels, and use a 1-2-3 block as the top clamp. I snug up the crank pin nuts, and then indicate between lathe centers from there. I use the hydraulic press to hold the wheels for torqueing the crank pin nuts. It doesn't take much pressure to hold the wheel assembly for torqueing. Indian SS wheels don't have the holding fixture holes like Harley wheels do, so they can't be tightened like H-D wheels.

[T. Cotten]

I Indian SS wheels don't have the holding fixture holes like Harley wheels do, so they can't be tightened like H-D wheels.

I've never bothered with the holes in HDs, Eric!

It appears only one wheel can be held at a time, and torquing laterally would rip my vise off the bench.

And since the wheels might be in and out of the centers a dozen times, I only worried about the vertical aspect of the indicators when it got close enough to make a difference.

....Cotten

[Buster]

Out of curiosity, what is the torque specs on crankpin and pinion/sprocket shafts on a Scout? There was just a discussion on difference in torque specs for a Harley 45 and big twin motors.

[T. Cotten]

Out of curiosity, what is the torque specs on crankpin and pinion/sprocket shafts on a Scout? There was just a discussion on difference in torque specs for a Harley 45 and big twin motors.

From my experience, Buster...

Seventy-five is as high as you can go on a 101 Scout cast wheel without splitting it. (Its a door stop now....)

Malleable "Z" wheels can go twenty-five more. Didn't late-model HDs have specs?

The thread diameters should give a reasonable equivalence. A quick web search brought up dozens of charts, but I always let the torsion wrench tell me.

....Cotten