Textile Mill Diorama

[zeeprogrammer]

A skill I wish I had was the ability to pick and match colors.
I can't even choose a proper shade of white.

The diorama is looking great John.

I've been following along. 

[J.L.]

Thanks Zee.

From what I can see as a novice to the hobby, the 4-jaw is most often referred to as the way to go to drill holes where centres have to be moved. But I am finding that rather than loosen and readjust jaws in new positions, the drill/mill does the job much more easily.

With the crankshaft webs, for example, the holes are 1 1/8" apart. No problem.

But I can see an advantage to reaming holes to finish size on the lathe. The reamer can drill right through into open space in the bore of the headstock.

With the table, enough packing has to be placed under the holes for the end of the reamer to finish its cut. The last 1/8" of a reamer does not engage the hole.

Offsetting for eccentrics makes sense to me for eccentrics, but I've heard that some fellows do them also on the drill/mill wth a rotary table.

Different strokes  to achieve the same goal I guess.

[J.L.]

The steel crank webs are complete.

Through hole is the axle diameter - 7/16". The other hole is a smaller 13/32" hole to allow the crank pin to have a shoulder.

I am not sure how to turn the crank pin. It sounds simple to just take a piece of 7/16" rod and put a 13/32" x  3/8" shoulder on each end.

A 7/16" rod in my chucks does not run true. AlsoI have had little luck removing a part from the chuck and turning it around. Once it leaves the chuck all bets are off that both ends will be concentric.

If I started with 1/2" bar stock I could face and turn the right 13/32" shoulder and check its diameter with the crank web hole; turn the 7/16" through hole and check it again with the crank web through hole; but the left shoulder could not be checked physically with the crank web. Only after the crank pin was parted off could it be trial fitted to the crank web to see how close I came to the correct diameter.

But everything would be all turned in one go without removing the bar from the lathe. I'me sure 1/2" bar stock could hang out far enough  from the chuck to do this.

Something to sleep on...

[Chipswitheverything]

Hi John, I would tend to go along with the thought of turning the pin at the one setting in the chuck.  Assuming that the 13/32" holes reamed (?) in the webs are identical in diameter  ( in any case, you can check the similar fit of both on the first section that you turn down ) , then your measuring of the inboard turned section is just using the micrometer as a "comparator" with the reading for the dia. of the accessible bit of turned length .  Particularly if you use the friction thimble on the 'mike to ensure similar pressure.
 If the diameters are nicely the same, then it should be fine!     Dave

[J.L.]

Yes Dave, I turned the crank pin from 1/2" round bar all in one go.

Mind you, It took three pins before I got it right. 

I think the moment of truth for everyone who makes the crankshaft like this is when it is set up after cutting out the web and watching to see if the flywheel is wobbling all around.

In theory, making the shaft like this should work, but picking up the hacksaw... well...

[J.L.]

It is recommended that the Loctite in the crankshaft and crankwebs set up for 24 hours before pinning.

So a little bit of panelling in the shop is being undertaken.

Get a grip...

Also, a sneek peek at the boiler below the bar clamp.

[J.L.]

Back to some metal.

It is interesting how different companies cast their metal and the level of precision that is realized when the parts are cast.

Here is a photo of two castings. You can guess in an instant which one is cast in England by Stuart Models. Some have recently criticized them for the quality of their work, but I find their castings crisp and exact.

A  takeoff pulley from the Stuart line is going to be modified and used on the Bolton engine. They suggest making the pulley from large bar stock, but this casting has so much character with its deep insets.

I would like to lighten the look of the flywheel quite a bit by reducing its OD. I remember when I was making the paper vertical steam engine model, the takeoff pulley was very wide and thin. A nice look I think.

[Ramon Wilson]

Hello John - well I finally caught up and have been through all your images. It's looking truly 'special'  I love those shots with the 'peek' of the boiler showing through the arch - this is going to be yet another fine display once completed for certain. That recessed door is (very) effective too 

Incidentally I've built a number of crankshafts but have always made the shaft in two parts eliminating the need to hacksaw and machine the inner faces to clean up. Also, if your fits are right and you are using a high strength retainer (Loctite 638 -ish) you should be able to pin within an hour or so. If you pin from the end of the shaft rather than across - you still get two shear points but only one area to clean up 

Keep up this fine work 

Tug

[J.L.]

Thanks Tug.
 
Cutting the arc or crown on a soft bronze or aluminum pulley is easy to do with this jig.  A cutting block is mounted on a bar with a hole in it at a predetermined radius to create a pivot point for the cutter. It cuts a symmetrical arc on the face of the pulley as you swing the cutting block back and forth and then slowly advance the cross slide to repeat the process.

But this jig was not robust enough to handle cast iron. I got lazy and tried to use it anyway. The finish on the pulley looks like the tread on my winter tires!   

But the arc is true and centred properly. 

Time to get out the files and emery cloth...

[J.L.]

That's better...

[b.lindsey]

That finished up very well John. Sometimes there is no substitute for elbow grease

Bill

[wagnmkr]

Looking very good John ... that looks like a perfect profile for the belt drive.

Tom

[J.L.]

Thanks Tom,

I always find it fascinating when watching a belt centre itself on a crowned surface. It just does.

Hi Bill,

Yes, elbow grease did the job. As a matter of fact, I may just file the arcs on the other softer line shaft aluminum pulleys.

I understand you have retired. Welcome to the club. I've been a member so long now, teaching was another life. 

Cheers...John

[ddmckee54]

John:

Is that as thin as you are going to make the flanges, or are you going to turn the inside of the pulley too?  Since this is a power take-off wheel and not a flywheel it really doesn't need the mass.  You just don't want to go too thin and make it fragile.

Don

[J.L.]

Don, I'm going to cut my losses and quit while I'm ahead with what I've got now. I agree about less mass required, but I like the look of the pulley as it stands now. Did you see the paper one above?

Don and others, I need some advice about whether to use spring pins or solid steel bar to pin the crankweb and crankshaft. The spring pins would put less percussive force and stress upon installation. Solid pins would leave a clean, almost invisible face. But hammering them concerns me.

The diameter is 1/8". Regardless of what happens the pins will be installed with Loctite 680 Retaining Compound. It is advertised as 'slip fit'. The spring pins would be more forgiving and more goop would go in with the pin. A tight, hammered fit would not take much compound in with it.

Thoughts?

John