Zee Needs Popcorn

[propforward]

That's where experience comes in. I was really afraid of melting the brass. (I did that once with aluminum.)

I completely agree with all your sentiments.

I seem to remember, in regards to annealing aluminum specifically - once upon a time, back in the UK in metalwork class - this was when I was 10, and when they still taught the use of lathes, mills and tools in school - we had a project which was to make a simple aluminium coat hook. So it involved cutting, drilling and bending / forming on a jig. Good fun. Anyway, the shop teacher showed us how to anneal aluminium with a hand held blow torch. First we coated the aluminium part with liquid soap - just smeared it on - then heated it. Once the soap turned black, it was done. A brilliant trick, and we could bend and curve that piece of aluminium with ease.

I don't remember many things, but I do remember that. Of course, I've never needed to do it since, but now I think I'm going to think of some sort of aluminium bracket for something, just so that I can do that again.

I don't recall it being difficult to clean the black soap off, but that was a long time ago.

Anyway - there you are. 

[zeeprogrammer]

Those are short and thick pieces to bend, so it's easy to understand the difficulty.

Just to clarify...I wasn't trying to bend them when they were that short.
However, you do point out one of the mistakes I think I made.
I was using a long rod. The idea being to thread an end, anneal it, bend it, cut it off, then do the next spoke.
So when I was trying to anneal the end I was going to bend, the rest of the rod was a heat sink.
I should have cut blanks, maybe 3 inches long, thread, anneal, and bend.

Although, as I mentioned, threading first left me too little rod to clamp onto. Or there may have been another way.

@Stuart - I didn't know one could anneal aluminum. I'll have to remember that (and the trick).

[crueby]

When annealing the brass, the color reached is the guide. Do it in dimmer lighting or it does not show well. Heat till the area being done is a dull red, and you are done. You dont need to keep it hot for a long time, and cooling slow or quenching makes no difference to the results in brass or copper.


What may have been the issue: With that thick a bar, it will work harden again during the bend pretty quickly, so you need to bend till you feel it stiffen up, then reanneal it again for more bending distance. When doing boiler end caps in thinner copper, it can take half a dozen cycles.

[zeeprogrammer]

Rats...or more strongly 

Squared up some brass, put it in the 4-jaw, faced, center drilled, and drilled badness.

I don't have small enough boring bars so I intended to drill 31/64 and then ream.
But as soon as the drill got past the angle of the center drilled hole...everything went wonkers, the tailstock chuck started spinning, and then everything stalled.

I had half expected it so was well puckered.

Lowered the speed a little and had at it again and fed with a tad more strength.
All went well and then reamed.

The result is that horrendous step inside the bore (see pic).

Thinking to myself...maybe it'll be okay. Perhaps the piston is thick enough and won't go so far as to hit the step.
So I flipped the part and faced to length.

Gosh darn it.  I had about 1/8" to take off and should have done just a slight face and taken the majority off the end with the step (effectively reducing the step).
And gosh darn it.  When I flipped the part I got it backwards and the cylinder bore was no longer on center. Not a real issue but I had intended to put a slight chamfer on the rim of the bore.

I wasn't rushing. I wasn't interrupted. I was dumb. 
Since retirement, I don't believe I've made a single part correctly or to spec. Sigh.

Anyway...some questions...

1) Do over?
2) Step up in drill size rather than in one go?
3) Forget drilling and reaming...get a proper boring bar?
4) Forge on and do the holes, ports, and mill the round. That'd be good practice.

#4 is a given. Thoughts on #1 - #3?

Is it 5 o'clock yet? Drat!

[Tennessee Whiskey]

First of all, if you have to wait on five o’clock and you’re retired, that’s a problem  . Secondly, since you are retired and it’s such a small bit of stock, I’d go with one through three 

Cletus

[zeeprogrammer]

First of all, if you have to wait on five o’clock and you’re retired, that’s a problem  .

Any earlier would cut into machining time.

Hmmmm. Not necessarily a bad idea. 

[crueby]

Get a proper small diameter boring bar, I have one that goes down to about 1/4" diameter hole and love the finish I get on cylinder bores. If the one you have looks like the one you pretzeled the other day, that is more like the ones you put in boring heads on the mill, there is another type meant for the lathe that has a smaller starting hole needed and better reach, you can find ones that take inserts which take out the resharpening issue. Mine was a gift from a retiring machinist, so I don't know what brand it is. Here is a picture of mine:

With a proper bar, you can start with a small hole (much over 3/8" drill gets grabby if you feed too fast, I like to start at about 1/4" and bore from there) and work up to whatever you need in multiple passes. The little bar I showed has been used on everything up to my Corliss cylinders. No need for reaming, just bore directly to size.

[zeeprogrammer]

I do like boring better than drill/reaming when the hole gets above 3/8. I've had very little luck bigger than that.

I don't worry much about being able to do the holes/ports but I do intend to practice milling the curve on the cylinder.

Sigh. 28 more minutes.

[b.lindsey]

Drats indeed Zee. I would make it over as you won't be happy with it otherwise. A.R. Warner has a nice boring bar in several sizes. I don't think their smallest will go down to 1/4" but should work with a 3/8" starter hole.

Bill

[zeeprogrammer]

I think I need Chuck's recliner.

Must not have tightened down enough or tried to take too much of cut.
Pulled the part right out of the vise.

I knew I should have stopped at 5:00.
It is now 5:45.

Cheers. 

[crueby]

Ouch.

But, i been there, done that, will do it again, I am sure. Just had it on a couple of my track parts yesterday, slipped in vise and chewed down the side.
 

[b.lindsey]

Not a good day Zee. Guess that settles the remake issue though. Some days you're the windshield, some days you're the bug 

Bill

[Kim]

Aw man...
What a bummer, Zee!
I've certainly done this before.  And you just wish you'd stopped sooner.

But now, you can start fresh tomorrow and try again, right?!
Kim

[zeeprogrammer]

Thanks guys.

But now, you can start fresh tomorrow and try again, right?!

Perhaps. Or a day or two or three later.
It's well after 5 now. About to finish the first sheet. 

I don't have a picture yet...but I did finish rounding the cylinder. I should have made more passes at different angles but for a first time I'm fairly pleased with it.
Most important...I managed that point where the curve meets the straight.

So the day ends up okay...and I'm feeling good. Decent anyway. Okay for sure. Better than an hour ago.  No pain.  

[zeeprogrammer]

Here's a pic of the 'practice' cylinder.
Overall I'm happy with it. More passes at angles, or a different setup, might have been an improvement.
I'm especially glad the junction where the curve hits the straight seems to be good.

It also turns out I have a boring bar that will fit within a 7/16 hole. That may do to get to 1/2".

I do have a question about drilling up to 7/16".
All in one go? Or go in steps? (I've tried that before - just once - and it wasn't good.)
If I go in steps...what step size?

This is brass...which never seems to like being drilled.