Dime Radius or Nickel Radius?

[bbb]

Here's an illustration showing the different minimum coin-sized curvatures that "fit" on different size tips - i.e., that span at least 60 degrees of arc (so maximum spin can be applied without hitting "off the edge" of the tip).

pj
chgo

View attachment 729276

so on a 12 mm shaft a nickel or dime radius is smaller than the ideal (quarter per your diagram)
whats the theoretical downside to having a smaller size radius ie dime or nickel?
is there a PRACTICAL downside?

 

[Bavafongoul]

Have you ever seen the videos where guys roll the shaft on their lap while shaping the tip with sandpaper?

I haven’t but I suppose it amounts to a slower motion substitute for a poor man’s manual lathe technique.

 

[Patrick Johnson]

Here's an illustration showing the different minimum coin-sized curvatures that "fit" on different size tips - i.e., that span at least 60 degrees of arc (so maximum spin can be applied without hitting "off the edge" of the tip).

so on a 12 mm shaft a nickel or dime radius is smaller than the ideal (quarter per your diagram)
whats the theoretical downside to having a smaller size radius ie dime or nickel?
is there a PRACTICAL downside?

Sorry, my mistake - I meant to say "the different maximum coin-sized curvatures" (corrected now in the original post).

Smaller radius is OK - with a larger (flatter) radius you can't apply maximum spin without hitting "off the edge" of the tip.

pj
chgo

 

[Rusty in Montana]

I've not seen the video of people rolling a shaft up and down their lap , I've done it many times and it works quite well if you don't have a lathe .
One thing's for sure you have to pay close attention and use some painters masking tape to protect the shaft and ferrul

 

[Flakeandrun]

I've not seen the video of people rolling a shaft up and down their lap , I've done it many times and it works quite well if you don't have a lathe .
One thing's for sure you have to pay close attention and use some painters masking tape to protect the shaft and ferrul

Absolutely! I had to get someone to put a new ferrule on my snooker when I first learned to re-tip my cue as a teenager. Brass scuffs up so much worse than a pool cue ferrule.