Full size Cretors from castings

[black85vette]

I am off on a new adventure. Bit off a big chunk this time. Looking at a box full of parts and the first thing that strikes me is how different this is than anything else I have done. Up to this point I was feeling pretty comfortable thinking through a sequence of operations that will give me good reference points in an order that makes sense and ends up with parts that line up, are square and concentric. Now I am looking at parts with ZERO finished surfaces. None of the sides are square or parallel. Also became comfortable with trashing a part when I screwed up and just making another one. Oh no, not now! Now I get ONE shot at getting it right.

Castings are from Cole's Power Models. Since this is my first casting set I can't give a comparison to others. All the parts appear to be fine. The plans are a couple of generations old copies. Still readable and I can always check a mating part to verify a dimension if necessary. Had a duplicate set made for use in the shop and "just in case".

Should be interesting. I plan on starting with the crosshead guide. Looks to be one of the more complicated and critical parts to get right. I will need to order or fabricate a boring bar. Nothing I have is nearly long enough. Then to the heads and cylinder since all of that has to line up.

In the mean time. I have plenty of flashing to remove and clean up to get done.

Expect a bunch of questions from me since I have no clue what I am doing. First question; where to start on the cross head guide? Any suggestions on the setup and order?

 

[Jasonb]

First thing is to set it up on your marking table and go around the casting lightly marking it out to make sure you get the best of teh casting, its no good machining a load off one end and then finding the other is too short. Take your time with this don't rush to be cutting metal

If the hole in the guide where it bolts to the cylinder is cast hollow then fit a hardwood plug so the centre can be marked out. If you give teh casting a spray of car primer it makes marking out easy. Shim it and pack it until you cam mark a full length centreline and teh vertical centre of the bolting flange.

As you only have a small mill I would suggest now mounting it on the lathe carrage so the flange can be faced and the trunck guide bored. This will then give you a true face to set all the other surfaces out from. You will likely need a between centres boring bar, and a boring head.

J

 

[black85vette]

If the hole in the guide where it bolts to the cylinder is cast hollow then fit a hardwood plug so the centre can be marked out. If you give teh casting a spray of car primer it makes marking out easy. Shim it and pack it until you cam mark a full length centreline and teh vertical centre of the bolting flange.

As you only have a small mill I would suggest now mounting it on the lathe....
J

No hole in the flange end so finding / marking the center should be OK. I will post a picture of it tonight.

I can take this over to my friend's Bridgeport mill if it is easier to do on a large mill.

 

[black85vette]

Here is the crosshead guide:

 

[black85vette]

Was planning on starting with the crosshead guide, but looking in the box of castings realized that there was actually a part I knew how to machine. The flywheel. Pretty straight forward.

Put the large hub in and used a dial indicator to get the spokes running straight in line. Then a center drill in the outboard hub for a live center. Then machine the outside hub. Flip it over and machine the large hub and side of the wheel. Flip back and do the other side of the wheel. Spins nice and smooth in the lathe. I will get the outside edge done next and then see about drilling and reaming the hole for the shaft.

 

[black85vette]

Spent some time this weekend getting the flywheel running true and cleaned up. Got the rim nice and shiny.


Also started work on building a jig to hold the cross head guide for boring. Need to pick up some stock to get that done this week.

 

[black85vette]

Flywheel is on stand by waiting for the cleanup of the spokes.

Back to the crosshead guide.



Did a light cleanup of the long side which I intend to use as my reference for the rest of the work.



Then I machined a block for the guide to set in. Made a recessed channel for it to sit in so it will always be square to the block. Then cut away some of the block so when I bore out the guide I will not hit the block with the boring bar.



Drill and tap for some all thread so I can clamp the piece to the block. Had to cut some out of the clamping pieces also.


Drill and tap the block so I could mount it on a right angle plate and bolt it to the compound slide of the lathe.

Need to get the material to make a between centers boring bar. Then have a shot at boring the guide. Will face and bore the hole in the end of the flange at the same time. At least that is the plan.

If I did everything correctly the top of the mounting block will be aligned with the work piece enough that I can use it with a dial indicator to set up the piece for the boring.


=build discontinued=