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Gonzo Machining for the Day

Not really today -- and not metalwork, technically.

You may have noticed me whining about needing a 2mm reamer on Friday. I didn't get one, and by golly on Sunday I needed to make something fit on a 2mm motor shaft. I had a 5/64" bit, which in theory is a bit smaller than 2mm, so I tried it -- no luck, like any other drill it's a bit oversize, and it was too big.

I thought "Ah ha! It's Delrin, so it's flexible! I'll use the 1/16" bit and see what happens!" No go -- the hole was too small, and I couldn't press the result on straight.

Then I thought "Ah ha! Delrin is a pain to machine because it squirms away from the bit! I'll drill a 1/16" hole, then widen it with the

5/64" bit!" Success! the 5/64" bit took out enough material for a good press fit on the shaft.

Never say die, and you may just succeed!

(Interestingly enough this also doesn't belong on _rec_.metalworking because it's for a customer project -- I needed a flywheel on a test article that I'm writing control algorithms for -- the _real_ metalworking involved was making the steel outer edge for the flywheel, that the Delrin hub presses into).

Reply to
Tim Wescott
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======== Thanks for "the rest of the story."

-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).

Reply to
F. George McDuffee

What do you mean work doesn't count? I made a crappy little tool consisting of a .55 dia pilot that fits into a pneumatic piston we have to put a U cup on. Round thing screwed to a piece of .50 x .25 x 3" stock that has a strategically placed 3/16" dowel pin pressed though the rectangle stock that just clears the edge of the piston by 0.010" so if they get the U cup started, a twist of the wrist spins it on.

Request from one of the ladies on my assembly line.

Of course the engineer had to approve it, he of course started improving it (we will see) but he did take it out to the line for use until he gets his tool made his way.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

Reply to
Wes

of a .55 dia

thing screwed to

(we will see)

Well, if he does improve it then huzzah! And if he's smart enough to get out of the way when yours works -- huzzah twice!

One of the things I needed to learn as an engineer is when you want to just get by with a crappy little tool, and when it's essential that you step back, take a deep breath, and really _design_ something.

I don't know if I'm there yet -- I've finished projects, fat and happy in a pile of new tools, then realized that I could have done the whole thing with a sharp stick and a rock.

Reply to
Tim Wescott

(we will see)

I found his solidworks file on the network today ( I have RO access to engineering) and inserted the piston into his assembly. He did okay. Drew it with the pin tangent to the piston but he has enough clearance for the fastener that I can slide the handle out enough for it to work as I made my proto type. I wanted the pin 0.01" proud of the piston on the diameter.

(worse comes to worse, I have a round file ;) )

I made a sharp stick and a rock product to prove my idea. He did pretty it up a bit. Wish I could post pictures of mine and his but that NDA is in the way.

He did okay, there was one change I wanted to make and he made it as I suggested.

I'm pretty happy with it.

Wes

Reply to
Wes

Tim sez:

"I don't know if I'm there yet -- I've finished projects, fat and happy in a pile of new tools, then realized that I could have done the whole thing with a sharp stick and a rock."

Right on, Tim ! It kinda differentiates engineers from the "inspired tinkerers" from whom most great ideas originate. It adds validity to the old saw which states, "Technology without mathematics would only be two weeks behind".

Bob (I are one) Swinney

Reply to
Robert Swinney

Nice make do. Did you ever find the machine shop suppliers in your area?

Reply to
Roger Shoaf

No -- I made do instead. I should look, though I'll have to push myself. It is rare for me to need something in a hurry -- over 99% of the shop usage is either hobby, stuff I already have tools for, or long range projects that can stay on the back burner for a while. So I almost never need something right now.

Reply to
Tim Wescott

Everyone does. If you can remember what tooling you have on hand, (that is starting to be an issue for me both at home and at work) your options have increased.

IOW, if you have three ways to do something, maybe you will think of one of them before buying something else. ;)

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

Reply to
Wes

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