Sunday, September 26, 2010

Pen Disassembly Parts Catcher

(Sorry, I forgot about this one. THIS is the last one for the night. REALLY!!!)

I often have to disassemble parts for one reason or another. A barrel needs to be refinished, or I don't like the end result, or I'm tired of the barrel on a personal pen, or whatever. The worst part, aside from getting a bit of skin pinched during the process, is chasing the little part after I've removed it with strong whacks from a mallet.

I've tried boxes. I've tried bags. I've tried all sorts of things, but the stupid part always ends up buried in my junk in the garage.

I got the idea to use a bench brush after seeing how much crap gets stuck it in when it's just hanging there minding its own business. I figured it couldn't hurt. So I gave it a shot.

Lay the brush on its back and aim the pen part directly into the bristles. If your brush is worn and the bristles are bent, I doubt this will work. But if it's relatively new, and the bristles are straight and soft, go for it! It works awesome! I did three pens and not one part went flying!

Pipe Mold Rack (Casting Polyester Resin)

(Last post of the night, I promise. I've been sitting on these ideas for a while and just need to get them out.)

I own lots of molds from expensive silicone molds where you cast the resin straight to a pen tube, down to lowly pieces of plastic pipe. The pipe are my favorite molds. They use less resin per inch of usable blank than a rectangular mold, and are more flexible than the "Resin Saver" molds with the pen tubes. Plus they're round, so the resulting blanks are easy to drill.

I use two sizes: 1/2" and 3/4".  The small one is for Pentel pencils and 7mm kits, the larger one is for everything else. I also use 2" pipe for "bottle stopper" sized castings, but that's outside of this article.

Anyway, the biggest challenge to using the pipes is how to keep them standing upright both during pouring, and when moving around (I'm ADD... I can never do only one thing at a time!)

If simplicity is brilliance, I should call MENSA. I made a rack to hold 'em. Took two lengths of "white wood" from Lowes (1x4 aka 3/4" x 3.5"), used a 1 1/4" forstner bit and cut holes. The top board got the holes all the way through, the bottom board got them 1/2" or so. Ripped some scraps from the wood and fastened them with Kreg pocket hole screws.Slapped a coat of garnet shellac (what else am I gonna do with that stuff?) on it to seal the wood. Then sanded smooth and put a buttload of wax on it with the buffer to help keep drips from sticking.

Works a treat! First cast is in there now. I love it! I can't believe I didn't think of this before!!!

Dust Collection at the Lathe

I picked up a 2hp dust collector off Craigslist for $50. I haven't had the $$ to get a proper hood to mount to the lathe, but having a DC at the lathe makes a HUGE difference in how much mess gets on the ground and in my face.

So I bungie corded the bare hose to my tool rest banjo. Works great!

Polyester Resin and Plastic Cups

Yup. Polyester resin and plastic cups don't mix. At least not the ones with a "6" in the recycle triangle:

I was out of my usual wax coated paper cups, and grabbed some of these. Ugh. Don't do it!

Tuesday, September 14, 2010

Delta 46-700 Lathe Reeves Drive Warped Pulley

Video at the end of this post.

I noticed last week that my lathe was making more noise than it should. Being a Reeves drive, it already makes a fair amount of noise, so it took a bit for me to catch that it was louder than it should be.

A Reeves drive is a pulley system that allows infinitely variable speeds while keeping the motor speed consistent. It does this by moving the two pulley halves further apart for slower speeds, closer together for faster speeds. The V-belt moves in and out, effectively changing the pulley diameter.

It's a good design and less expensive than an electronic speed control. Being mechanical, it does have its drawbacks. Namely that parts wear and break. When I bought this lathe (for $100) the outboard pulley bearing set was broken. I installed the new outboard gear and it worked fine, but noisy.

I pulled the cover off today to find out why there was so much noise. I found three problems:
  1. Inboard pulley mounted incorrectly-
    The inboard pulley set screw was on the motor shaft, not on the key as it should be. This made it impossible for the key to be fully seated, making the highest lathe speeds unavailable because the two pulley halves couldn't get as close together as they should.
  2. Belt is old and stiff-
    The belt was old and dried out, resulting in bumps preventing the belt from traveling smoothly.
  3. Warped pulley-
    The inboard pulley is warped. This was slapping the belt around, causing a lot of noise and some vibration.
You can clearly see the belt slapping around in the video below. The low resolution of the video doesn't really show the pulley, however.

A new inner pulley is only $15 from, but it's still annoying to have to replace it. Especially considering how slow their shipping is.

At least I've found the problem!