The Home Machinist!

I am sure this has been written about. That said, how does everyone bore cylinder castings too large to turn on a faceplate or in a four jaw. Does anyone use a milling machine?


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Fred,
this sounds like a topic that belongs in the regular Live Steam forum rather than the marketplace.
Jim

Ohhhhh


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Fred:
To answer your question, Yes, I have bored cylinder sets on the mill.
Move your question to the Live Steam topic forum (where you will get more useful responses) and we can continue this in detail.
RussN

Rent some time on an HBM. Tis what they were designed to do.

Mountaineer.

Down feed on a Bridgeport style mill will let me bore my steam cylinders, but there isn't enough spindle travel to bore the valve cylinders without some manipulation.

In an old Live Steam, there was a photo of cylinder being bored on a Bridgeport style milling machine with the head turned horizontal and the spindle parallel to the table. The table provides the travel.

Some have mounted then on the cross slide of their lathe and bored them with a boring bar between centers. Easier if your lathe has t-slots on the cross slide.

I guess it all boils down to what type of equipment you have available to you.?...in my case, I have always used a horizontal boring mill. ...a large machine, but it makes mince meat out of boring cylinders

Not hard to bore single steam cylinders on an ordinary metal lathe. As long as there's not a lot of bulk of extra metal on the casting in the way of mounting them on the bed. There's a couple ways of doing it. One of them would do quite large cylinders for the size of lathe.

My lathe does not have T slots in the saddle. I got a small piece of aluminum tooling plate, a hunk-o-steel that I turned to match the "spigot" that is on the bottom of the top-slide, and bolted them together. Take off top slide, install tooling plate ass'y, ready to go.

The quill on my mill did not have enough travel to do this, and it was going to be difficult to hold the piece at the correct 5 deg. angle.

I have bored a long (6") cylinder on my mill using the power feed knee for the vertical motion.
It worked perfectly.

I also machined the cylinder set for my Mikado on a tight DRO-equipped Bridgeport mill.
I milled the saddle and mating cylinder flats, Bolted the three pieces together, and secured them to the mill bed cylinder head up.
I was then able to face and bore both cylinders, then drill and tap the head ends. Everything was square and planar.
Next I flipped them over, secured the machined flat cylinder head ends to the table, and faced, drilled and tapped the exposed ends of the cylinder assembly.
This assured assembly alignment and worked very accurately. The DRO helped immensely.
The engine operation verified this method.
RussN

Here's how I did mine. In the first photo the cylinder block is attached to a t-slot cross slide. As Rudd points out above, you can do this without the t-slot cross slide. The fat boring bar is between centers to minimize any flex of the bar. You can see the toolbit sticking out of the bar. In the second photo, the cyl. block is faced on one end with a toolbit in a block on the face plate, without moving the cyl. off the cross slide. The cross slide is run in and out to make the cut. Thus the face is perpendicular to the bore. This face then becomes the reference surface for the other cuts on the cyl. block.

Thank you all and sorry for posting in the wrong spot. [IMG]https://uploads.tapatalk-cdn.com/201912 ... 3e6502.jpg[/IMG]. Big cylinder little mill. I will be doing a cross slide project I guess.


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