El Grande ballpoint fun....

[redfishsc]

Well, I have a new love/hate relationship.

A while back I made my first El Grande ballpoint twist. I LOVE the mechanism (as well as the Perfect Fit, same tranny).


But today, I blew up the THIRD one in a week. So far I have a 70% success ratio on this baby. It's so thin-walled! Anyone else have this much fun?


Here is the problem: if you make the pen using the bushings you are given, the lower barrel is too fat to fit into the center band and the twist action is very stiff and cheezy.

IF you turn it down thin enough to fit inside the center band without it binding, you are a half-micron from nuclear fission.

What hurts the worst: I blew up a lovely osage burl and an azurite trustone that took me an eon to turn (that was only the lower barrel!).


Has anyone found a way to solve this?

 

[turned_for_good]

Sharp tools and light cuts.:wink:

Since I ususally do a CA finish on my pens, as I get closer to the finished dimension I coat the blank with CA to help stabalize it more and keep it together. No accelerator as to let it soak into the wood as much as possable. This seems to raise my success ratio on thin walled pens.

 

[jskeen]

180 grit gouge?

 

[Ligget]

Sharp tools and light cuts.:wink:

Since I ususally do a CA finish on my pens, as I get closer to the finished dimension I coat the blank with CA to help stabalize it more and keep it together. No accelerator as to let it soak into the wood as much as possable. This seems to raise my success ratio on thin walled pens.

Exactly the way Benjamin explained! :biggrin:

 

[leehljp]

JSkeen gets my vote. On fragile woods, I turn down to no closer than 1/16th inch or 2 mm of finished size and sand it down from there. It takes more time but but I get to see delicate woods get to the finished sizes without worry about blowouts, or chips.

I do my sanding at slower speeds. In the end, I figure I have spent 10 or 15, or maybe 20 minutes on the last mm or two, which in the grand scheme of things, is not to much extra time for sizing a fine pen.

I go through 180/220 and then the last half mm, use 320/400. Haven't lost any doing this.

 

[redfishsc]

Well, I have the "sharp tools" part right and I generally do take light cuts (I get the small whispy birdnest of shavings on my hand and a glossy sheen on the wood, so I figure it's light). I've suspected that I have the angle on my skew (the bevel) too long, because it has a tendency on some materials to catch a bit more than it did before I ground the current angle.


As far as the sanding, I'm going to have to on this one! I'm glad I have a Klingspor locally to buy scrap sanding belts cheap (the BEST sanding material I've found).

Thanks for the help all!

 

[rgordon]

As Tim Yoder says on his turning show on PBS Sandpaper is our Friend. Ralph

 

[redfishsc]

As far as the sanding, I'm going to have to on this one!

I just read and re-read my own sentence a dozen times and I still have no clue what I was trying to say. Lousy typing...

 

[PTJeff]

remember that sandpaper IS a cutting tool

 

[MobilMan]

When does Tim Yoder come on PBS. What day?

 

[marcruby]

I would venture that the problem you are currently experiencing with catches is because your hands haven't caught up with the change in the bevel yet. The longer the bevel the easier it is to lift the blade slightly and cause a dig. I like a bevel slightly longer than the 1.5 x thickness rule. I've discovered over time that I have a heck of a time adjusting to someone else's skew now. I just have to bring on of my skews with me if I'm 'visiting.'

Marc

Well, I have the "sharp tools" part right and I generally do take light cuts (I get the small whispy birdnest of shavings on my hand and a glossy sheen on the wood, so I figure it's light). I've suspected that I have the angle on my skew (the bevel) too long, because it has a tendency on some materials to catch a bit more than it did before I ground the current angle.

 

[redfishsc]

I'm with you 100% on that, Marc!

I still am amazed at just how thin you have to turn the lower barrel to fit into the center band on this kit, I'm afraid if I cut it any thinner I'm going to start a nuclear fission reaction.


Oh, BTW I discovered that you can solve a lot of this issue by using a 29/64th drill bit to eat the threads out of the center band. Apparently the center band on the ballpoint was just grandfathered over from the fountain pen and has the threads inside (which serve no useful purpose on the ballpoint). Cutting them out with the drill bit is really easy, cuts cleanly (delrin is soft), and works like a charm.