Novice Machinist : Metal Stock

[Antman]

Well, you guys pretty much turned me away from looking for stock at the scrapyard. Not much has been posted about the use of tractor weights as stock. I want to start with my shaper by first making as accurately as possible, a pair of V Blox, Then I want to try making a pair of dovetails, the screw when we get the lathe. Aren’t real World blox and slides made from cast? We have a brazed on carbide roughing tool and for the rest HSS square stock which we will grind ourselves. Should we try to preserve at least one surface with the cast skin? Are there strength or stability issues with machining all surfaces? I want to make tools that I can use before I tackle a simple engine, will the CI be a waste of time, just something to play with, get used to the Machine? Are there not cleanliness issues with CI, the shavings being abrasive to your machine?
Also I have some of the Work Shop Series books and will be making some of their gadgets. I’m off again to the big city soon, Durban this time, 500km ( I won’t drive long distance again in a hurry, just settle down to some serious machining ) to visit me old Mom, buy a lathe and, I suppose metal stock. I don’t want to machine much in aluminium or brass. What good steel should I be looking for in Flat and Round, suitable for a novice who wants to get it right first time and make tooling that I can enjoy later?
Thanks for all your help, I really appreciate the mentorship of you guys who answered my threads.
Ant

 

[Dhow Nunda wallah]

Ant, as far as I've worked CI, the only "cleanliness" issue is possible sand inclusions from casting.
Fettle the material with an angle grinder before introducing to to your machine shop and you should be ok.

The cleanliness relates to graphite in the iron (search on "SG cast iron", spheroidal graphite).
It's filthy stuff to turn, but won't harm your machine any more than pencil graphite.

Rgds,
Lin

 

[b.lindsey]

Ant, if you can find it "leaded" steel machines like a dream. The common version around here (Southern USA) goes by the name 12L14 and is used extensively in screw machine shops, etc. Other than that the milder steels like C1018 would be a second choice.

I disagree somewhat as to the CI "dust." I have always been told that it IS abrasive, even more so when mixed with cutting oils or fluids. What experience I have turning it (CI Flywheels, etc.) I didn't leave it on the machine long enough to find out. Generally it is machined dry so the dust can be vacuumed from the ways and then cleaned with a rag.

Bill

 

[Dhow Nunda wallah]

wlindiii, agreed, re coolant
I've always machined CI dry, with sharp HSS tooling.
Otherwise, I've never had a problem except for the dirt.

One tip is to put a NIB magnet inside a plastic bag on the ways or saddle under the tool.
The magnet grabs most of the the swarf before it spreads too far.
When you finish, lift off the bag and magnet and turn the bag inside-out, tie the neck, then remove the magnet.
You can then dump most of the mess straight in the bin.

We used to use old telephone magneto or speaker magnets for this. Now that small NIB magnets are available for a coupla bucks, the trick can be used on small home lathes.

Rgds,
Lin

 

[tel]

Don't be dissuaded from seeking materials in the scrap yard - probably 80% of my stock comes from there.

Cast iron is generally pretty good stuff to machine one you get under the skin - no point in leaving the skin on one side, clean it up all round. Most bits of CI are ok - even window sash weights (despite what some people will tell you).

Haven't come across any unwanted tractor weights to try, but I do have a 2' solid flywheel (ex traction engine I think) that I am very tempted to attack with the angle grinder. For tool bases and bodies etc, CI is the best of the best IMHO