Plastic roll pin

FWIW, 3/4" pipe and PVC electrical conduit is 1.050" OD by 0.824" ID.

-jsw

"Tom Gardner" wrote in message news:UK6dnUS5vIjDFlzOnZ2dnUVZ snipped-for-privacy@giganews.com...

On 7/12/2014 1:06 PM, Carl Ijames wrote:

They will supply tubing 1.040" UD x .500" ID and want it bored to

11/16". I wonder if their original size of 1" OD x .75" id could be stretched open to provide more holding power? That would eliminate yhe boring op. [/quote]

I figured I better check if you are going to try this, and my memory was a little off. Here's a table I found online for lots of different plastics, handy as a guide

I was using 1/32" thick by 1" Delrin strip that was straight, cutting 9" lengths, coiling them inside a 1-3/4" od stainless steel tube, putting four side by side and four layers. Any more layers and the id was too small. Put that into a toaster over that is room temp-ish, set to 325F and turn it on. It was a big oven that could do a 12" frozen pizza so it had a decent amount of heater power. I used the convection toast setting so the fan, upper heaters, and lower heaters were all on. Reached temp in about 20-30 minutes and the timer turned it off after 45 minutes so 15 minutes at full temp for the soak. Let cool to under 175F, maybe 45 minutes, so I could grab it barehanded, pop out the coils and reload. That gave me coiled rings I snapped around 3" iron pipe as trim rings that would grab tightly enough to stay put but if the annealed diameter got too small they wouldn't lay flat and look good. I wasn't going for a perfect anneal, I just needed them to hold the coiled shape. Anyway, that table recommends a much slower heat and cool, soaking at 300F, but that is a general recommendation for machined pieces up to 1/4" thick. Your pieces will be thinner and I don't think need the greatest precision so you can rush it a good bit. Yes, I'm sure the 1" od would work fine - you can even make the slit 1/4" since it will grow about 1/8" when you anneal to the larger dia.

----- Regards, Carl Ijames "Tom Gardner" wrote in message news:UK6dnUS5vIjDFlzOnZ2dnUVZ snipped-for-privacy@giganews.com...

On 7/12/2014 1:06 PM, Carl Ijames wrote:

They will supply tubing 1.040" UD x .500" ID and want it bored to

11/16". I wonder if their original size of 1" OD x .75" id could be stretched open to provide more holding power? That would eliminate yhe boring op.

The more you tell us, the more I see why they're still looking for a supplier. I'd run away if I were you, Tawm.

P.S: What's their lab guy's name, DeweyBob? (as in "Hey, hold my beer and watch this!")

I can see his point. It's extremely statically charged and sticks to everything. I've slit PVC pipe and don't think I want to try THAT again.

One would think filling it with a fast setting epoxy / resin would be as good or better and cost less.

Buy by the 55gal drum and inject.

When they installed a new telephone pole in my side yard - I have 1800 foot of 2-phase HV to the house and shop. :-) They had the pole set and the hole a bit large but not much. Before setting, they dumped a mixed up resin and poured it in the hole. Then dropped the pole and another 5 gallons of the stuff was poured around it. The two men then did heave plenty of dirt atop of the hole and stood atop that! They rose by maybe 6" as the plastic resin expanded and filled every crack. It also helps protect the pole from insects. No hidden holes to allow the pole to lean after a rain storm.

Martin

I like it! 1" dia x 4" long = 3 cu in =

I'm sure their markup on the finished product will cover the rework cost. Perhaps they'll make $5/ea profit on these reworked brushes vs. $10/ea on the new correctly built ones. $50k profit is still plenty good.