British 0-4-0 Toy Locomotive: he said

[mklotz]

Use the 4J. It will give you a better grip than you can get with the 3J.

In the (likely) event that the workpiece is thinner than the jaw thickness, back the wp with a ring or similar so that it is supported against the (axial) forces of a trepanning cut.

Aside: Whenever possible collect offcuts of various diameter pipe to make just these sorts of spacers. (I have a box with about a dozen different sizes.)

One can unwittingly exert a lot of force with the jaws of a 4J. It's very easy to mark brass workpieces. Use some shims to prevent denting finished surfaces.

 

[Deanofid]

I think Marv has your solution, Zee. Or, make a split collet from aluminum, (or whatever) and use the outside three jaw, and have at it. That way, you won't have to concern yourself with jaw marks, either.

What are the dimensions of the caps?

Dean

 

[zeeprogrammer]

Thanks Jim. That's a method I've seen in other threads but never think about on my own. I have some practicing to do with soldering before I can work on the fuel tank and boiler...so I've made a sticky note to remind me to try your suggestion.

Thanks Marv. That was what I did when I worked the drive wheels. I now have 3 spacers in my collection. When I made the space for the drive wheel I drilled a hole in the center so it was easier to drill and ream the hole in the wheel.

Thanks Dean. I've tried the split collet approach twice now with no luck (on other parts). Not sure what I'm doing wrong. I suspect the hole needs to be a closer fit to the part. I set the collet such that the split is centered between two jaws...I wouldn't think placing it closer to a jaw would help in anyway? (And I'm sure placing it under a jaw would be stupid. ;D )

By the way...if I made the collet it would have to be bigger than the part I'm trying to hold which I can't hold in the chuck because it's too big....see where I'm going? ;D Ah! I could cut a lengh off in the bandsaw and set it up in the mill to bore the hole then hacksaw the split. Hm.

1 and 3/8" OD, 3/8" long

 

[Deanofid]

I may have misunderstood this bit, Zee:

"I think the reverse jaws won't work either...the part will be to far inside."

I took it to mean the outside jaws wouldn't close down far enough, meaning they would be to big around. Maybe you meant the piece goes too far into the recess in the jaws?
Straighten me out!

I'll just put down here how I make a split collet. You might find something in it.
Usually start with a piece that is only slightly larger in dia than the work piece, but that changes a lot as needs are met for work holding limitations, and jaw opening.

Put the piece that will be the collet in the chuck, bore it through to where it will just take the work piece. I mean, a nice sliding fit, not sloppy. Talking about 2 thou for the work piece you describe, or even an easy push fit won't hurt. Then split it with a slitter or a hacksaw. You already know it will fit in the chuck, 'cause you made it there.

If the work piece is kind of thin, I make the collet the same way, but with a stepped bore, so the step will keep the working end of the piece proud of the collet, and can be use to locate for length if you have a number of the same pieces to make.

You have the slit in the right place, between the jaws.

By the way...if I made the collet it would have to be bigger than the part I'm trying to hold which I can't hold in the chuck because it's too big....see where I'm going?

Won't your outside jaws take 1.375" plus a bit for the collet?

Dean

 

[JimN]

Looking good Zee, nice work.

JimN

 

[zeeprogrammer]

I may have misunderstood this bit, Zee:

"I think the reverse jaws won't work either...the part will be to far inside."

I took it to mean the outside jaws wouldn't close down far enough, meaning they would be to big around. Maybe you meant the piece goes too far into the recess in the jaws?

Yes. I meant the part goes too far into the recess of the jaws.

As for the collet..what I meant is that so far...whenever I've put a split collet into my lathe and tightened down...the part is still loose. I'm thinking the hole for the part is just too big. A slip fit (?) is needed. Rather, a hole 'just big enough'.

I like the idea of a step in the collet. Neat. Thanks.

JimN...thanks. I appreciate that.

 

[mklotz]

If your split collet doesn't close, perhaps it is too thick to bend easily under the pressure from the jaws. If this is the case, it can be remedied by cutting a blind slot in the exterior of the collet opposite the full depth slot. Make the slot deep enough to weaken the wall so the collet can clamp together more easily.

On the 4J, can you superglue a ring or plate to the back of the workpiece to make it stand sufficiently proud of the jaws to accomplish what you want to do? Remove the glued part after the work is done by heating everything to weaken the glue, then tap parallel to the glue line with a hammer. Superglue doesn't have great strength in shear.

 

[zeeprogrammer]

If your split collet doesn't close, perhaps it is too thick to bend easily under the pressure from the jaws. If this is the case, it can be remedied by cutting a blind slot in the exterior of the collet opposite the full depth slot.

Ah! Great idea. I'll try it. Thanks Marv.

 

[DavesWimshurst]

Zee,
Perhaps two extra slots so all the cuts are equally spaced between jaws.
Dave

 

[zeeprogrammer]

I admit it. This is a rank attempt to get my thread up a page. I got nothing to show.

I started on the front and rear sheets (end caps) for the boiler.
Which means the cap is in the chuck during trepanning.
Which means the boiler that needs to have chrome sanded off can't be in the chuck.
Which means I can't use the boiler to determine the 'right' size to bore the cap to.
Which means I'll make it too tight (no solder flow) or too loose (no solder fill).

I told you it was rank.

Ah...I'll get close enough. It'll be okay.

 

[slick95]

It Worked

Still, I look forward to your progress Zee...

Jeff

 

[Deanofid]

Cheater, cheater, pumpkin eater.
When my build drops to the nethers, like yours, I'm just gonna bring it back with a story about the cat's latest hair ball episode.

Dean

(You'll do fine with the measurements, Zee!)
; )

 

[zeeprogrammer]

Thanks Jeff!

Sticks and Stones Dean.
I'll pack a few with the bon-bons for you when I come visiting. ;D

So...I managed to do some work undetected. Turns out she'd gone shopping.

Finished the front and rear sheets (end caps). That was more fun that I thought it'd be.

That hole will have a 'bolt' soldered through it and is used to attached the boiler to the front of the cab.

Here's a mock-up...

Some poster blue-tack is holding the brass bits on top of the boiler.

Boiler is getting a bit scratched...maybe should have put tape all around?

She's back. Time to weed and mulch.

I hate weeding and mulching.

 

[Foozer]

Thats starting to look real Cute

Few hundred pounds of rock salt will take care of them weeds for ya

Robert

 

[ozzie46]

Looking good Zee.

I know what you mean about yard work. Its that time of year.

Ron

 

[Deanofid]

Ah, it's beautiful, Zee. Really is.

Now get back to work!

Dean

 

[user 1493]

Hey Zee,

I live in a college town and it is amazing how many responses you get from an ad at the university offering $8.00 per hour for yard work. Fortunately for my wallet the kids don't know how much I would pay them to do the work.

Your project looks great as usual. You set a very high standard.

Thanks,

Jack

 

[putputman]

Zee, take Jacks advice. We won't squeal on you. That way we see that piece of art work running sooner.

 

[zeeprogrammer]

Hey Robert! Thanks. As for the rock salt...I'm sure it'll take care of weeds...and I'm sure my health will suffer as a result too. ;D

Thanks Ron.

Thanks Dean. I'm working! I'm working! She has roses and there's a holly tree in back. I'm getting poked enough. ;D

I live in a college town and it is amazing how many responses you get from an ad at the university offering $8.00 per hour for yard work. Fortunately for my wallet the kids don't know how much I would pay them to do the work.

Zee, take Jacks advice.

You guys got wallets? She took mine away after my last tool purchase.

Thanks for looking Jack and putputman.

 

[cfellows]

Ahh, look at that. That's a fine looking boiler, sure you don't want to leave it chromed?

Yuk, yard work. When I lived in Arizona, we had a yard full of rock with no grass in sight. We also had a landscaping service who came out once a month to trim the shrubs and smooth out the rock (no kidding). Now that I've moved to Texas, we have grass, such as it is, shrubs, weeds, and fire ants. And, since I'm retired (I think), can justify getting a landscaping service. I thin I liked it better when I had a full time job!

Chuck