Jump to content

Re-engineering the Shift Spring


Scud

Recommended Posts

I'm interested in 2.  Won't  there be a formal method for payment and receiving address?

 

Frank

 

Yes, after I am sure about postage cost I will give prices and payment options.  I think I might put some of the details in my profile, since that is only visible to members. 

Link to comment
Share on other sites

I want 2. One as a talisman, and one for an upcoming 'new addition.' And count me in for more if needed to get numbers up.

Wouldn't that make "three?"

Link to comment
Share on other sites

 

I want 2. One as a talisman, and one for an upcoming 'new addition.' And count me in for more if needed to get numbers up.

Wouldn't that make "three?"

 

 

I'm counting the one I'm "going" to need :whistle:      The Tenni is happy with her "fix" for now.

Link to comment
Share on other sites

 

 

I want 2. One as a talisman, and one for an upcoming 'new addition.' And count me in for more if needed to get numbers up.

Wouldn't that make "three?"

 

 

I'm counting the one I'm "going" to need :whistle:      The Tenni is happy with her "fix" for now.

 

Ah! Durn, I simply forgot about that coil spring. :thumbsup:

Link to comment
Share on other sites

I fitted one of the newly manufactured springs to the spare pre-selector. It shifts well. The short arm of the spring is noticeably longer than the original, and contacts the stamped steel part further out, by the shoulder (rather than in the curve).  Here's pics of how the spring fits.

 

IMG_7487.jpg

 

IMG_7488.jpg

 

IMG_7489.jpg

 

 

  • Like 1
Link to comment
Share on other sites

I fitted one of the newly manufactured springs to the spare pre-selector. It shifts well. The short arm of the spring is noticeably longer than the original, and contacts the stamped steel part further out, by the shoulder (rather than in the curve). Here's pics of how the spring fits.

 

IMG_7487.jpg

 

IMG_7488.jpg

 

IMG_7489.jpg

It will be difficult to predict the effect of this.

One thing, longer arm less force on the bend, since the spring angle stays the same or even reduces a bit.

That could be a pro.

 

Otherside:

The shoulder will introduce an other direction of the force on the bend. Possible with some friction. That a con.

 

 

Verstuurd met Tapatalk

  • Like 1
Link to comment
Share on other sites

Uh oh. The springs I made, and the drawing shows it to be shorter than that. They'll probably be fine, but  they are "supposed" to ride on the flat. From memory, the leg length from the center of the coil to the center of the leg is .7"  I wonder if they added the bend radius to the dimension?

Edit: here's the picture before adding a matching radius to the Mighty Scura. You can see the short arm is on the flat.

38811578495_b1f4dbb1dc_c.jpg2018-01-15_01-15-11 by Charles Stottlemyer, on Flickr

Link to comment
Share on other sites

I think the arm is 0.7 inches as you specified, but the hand-made ones you sent me were closer to the 0.62" measurement that you originally had on the drawing. However, the angle is 30 degrees on the new springs, not 1 degrees as you specified. The caliper is open to exactly 0.70 inches.

 

IMG_7490.jpg

 

I think we would be justified in refusing these springs just on the basis of the angle - and asking for another batch. But if we do, should I change the length specification back to 0.62"?  Or maybe the 30 degree angle (vs 15 degree as specified) has contributed the issue.

 

From what I can see, the spring will work. The short arm doesn't move around on the stamped piece - and so long as it can't slip off the shoulder it should be fine. (and it cannot slip off the shoulder - I tried).

 

Chuck - it might be good to talk this through. I'll be available this evening.

Link to comment
Share on other sites

From the spring calculator..

 

.071 dia. spring with 2.45 active coils. The spring calculator says this spring has 62.5 degrees safe travel. Total travel of this spring in service is 39+15= 54 degrees.

If it is truly 30 degrees, 39+30= 69 degrees.. that's over the safe travel limit. I'm not buying that. Yes, it would probably work. I've already tested one like that as a worst case scenario, and it went through a quarter million shifts without issue.

That extra .075" ? I'm not sure what happened there. Probably, I misread my scale? :huh2: I do remember crossing out the .62 right as I was packing the box to send to Scud. If so, I'll eat the cost of making new ones. 

Link to comment
Share on other sites

It's just play money, Docc, and everyone knows that play money doesn't count. :)

Count my PlayMoney in, then . . .

 

Seriously, though, if the product doesn't fit the working drawing, the manufacturer *should* square it away, yes?

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...