COMMON PROBLEMS MACHINING CASTINGS - MODEL ENGINEERING FOR BEGINNERS #8

[@gordonburns6721]

Hi Keith... a Yorkie here! My only observation (as an apprentice trained toolmaker) is that after the centre-drill operation, I would have drilled and reamed a good size smaller than finally intended (say 1/8 inch or 3mm smaller), matching the size of a 'standard' diameter tapered mandrel. Then after initial machining, we can force the flywheel onto the tapered mandrel (already machined work to the widest end), allowing the flywheel to turn freely between centres using a face plate and driving dog. This allows us to work on the flywheel from the rear face and boss, thus achieving perfect concentricity with the already machined front face. When done, knock the flywheel off the tapered mandrel and using a dial-test-indicator, centre the flywheel (within 4/1000 inch or 0.1 mm), which should be near enough for the balance of a steam engine flywheel. My father, now long deceased, was the most highly-skilled bench fitter that I have ever known. He was employed by Adamson's in Leeds (industrial sewing machines) as a 'sewing machine foot' designer for machines sewing things from hems and seams to buttonholes and buttons. I remember visiting his workplace in the late 60s and gazing upon his work, saying to him... How, Dad? How did you do it? The process was normally my Dad starting with a piece of Stainless Steel and the critical dimensions... hardly ever a drawing... he would then cut and shape the end result, using cold chisels, hacksaws, files and emery cloth... creating the correct piece for the job in hand. He was good! (nay... he was very good)! Simples! I absolutely enjoy your videos, so please keep them up! Best regards, Gordon

[@friotexas]

Bought some new small barbell weights for cheap and thought they would make great flywheels. Spent hours on my 9x19 lathe trying to turn it down. Used HSS then carbide inserts. Would not cut through specific locations. My lath was jumping around. Tightened the gibs. Still no luck. Gave up! Got on KZbin and finally found your video COMMON PROBLEMS MACHINING CASTINGS - MODEL ENGINEERING FOR BEGINNERS #8. Now I get it. THANKS.

[@davidrichards5594]

Keith: Absolutely the best machine shop camera work on you tube. I use the same sequence to re-machine flat belt pulleys. Your series should get anyone to order up a set of castings and build something. Dave

[@keithappleton]

+David Richards Thanks David for your kind comment :-)

[@oldsteamtoy]

Again an excellent video , both in presentation and the vast amount of education for your viewers. I feel you just saved me a lot of time from having to learn from my own experiences. Your videos are very informative and thanks for sharing your knowledge.

[@myfordboy]

Very well presented, I wish I could narrate with confidence like you.

[@keithappleton]

Thank You, it's only lots of practice doing it that makes it sort of flow. I don't use a script, I just make it up as I go along whilst watching the video footage. When I shoot the video of what I'm doing in the workshop I have a good idea of what the end product is going to be like.

[@jovevski01]

Hi champ, can you recomend some books or websites to start my hobby in building steam engins, etc I am finding hard to find drawings etc. Thanks and love your work. Keep it up I am sure many peps appreciate it cheers

[@keithappleton]

Buy old "Model Engineer" volumes from the 1950s & read the writings of LBSC :-)

[@nitro105]

I have had similar experiences, I once had to machine an 18 inch cast iron steering wheel and it "rang" so bad that i couldn't use carbide and run it at any speed so I had to use HSS and run it very slow, but until you get under the skin of the casting I had to sharpen every pass.

[@kgee2111]

Thanks Kieth. This explains why I'm having so much trouble trying to machine my flywheel casting. It's chilled! It's impossible to cut. They must have mixed in some Kryptonite! Not to mention the blowholes that are in it. The hub machined ok but the rim is impossible. I'll start over with a new one. Thanks again!

[@rustypanels1917]

Hey Keith, great video's you make. Very infomative and your explinations are excellent. Thanks for sharing your work.

[@MrCsigmund]

Thank you very much for your wonderful videos and your narration ! Makes me want to head down to the work shop and do some turning. Charles Sigmund

[@nitro105]

Have you ever tried to anneal a hard casting by heating and burying it in wood ashes to cool slowly?

[@chicagolathe-shopmaster-sh1680]

Wood chips will char and become charcoal releasing carbon and carburize your material, making it even harder.

[@hinz1]

Never tried it, but it should work, I guess. Cast iron already has so much carbon, that it hardly can take any more, so I doubt carburization would happen. It's all about heating it above a certain temperature and cooling it slowly enough, so that no martensite gets created.

[@rjordans]

You can also use some cat litter instead of the wood ashes. Try to get the silica based version, it gives you a nice porous material with good insulation properties that allows for a slow cooling of the casting. Get the part heated red and non-magnetic , keep it at that temperature for a while to make sure that it's thoroughly hot, and have it cool slowly buried in a bucket of the cat litter.

[@Unclejohntyskitchen]

Keith , brilliant videos . great to watch , you definitely get my like. can I ask were all you buy your castings from as im about to buy some myself . Regards Gareth

[@keithappleton]

+Gareth Johnston www.blackgates.co.uk

[@MustangGT4.6L-2A]

Hello Mr. Appleton i have a question, When it comes to machining metal do you need both a lathe and milling machine or can you get away with just one. I know that both have their own benefits to their use but im just curious. Thank you a ton.

[@keithappleton]

A Lathe with a milling top slide will be fine for most small jobs.

[@NamLeLa]

How do you fix casted part with draft on lathe? I’m making cast iron gears up to 66in in diameter...

[@andyg3]

i remember reading somewhere that you can get rid of a chill by heating the casting up red hot and letting it cool slowly.

[@johanengqvist4333]

It's called tempering

[@DeepPastry]

Close, but not really. Instead you'd need to anneal the part to soften it. Tempering is very close to annealing, but it's best to soak the part at temperature for an extended period and then use a very slow cooling time. The basic differences are time at temperature and cooling time, plus usually higher temps to temper compared to annealing. I just found it pretty interesting that chilling a cast part is/was done to create hardened surfaces before using hardened steel was common. It's still used in some industries to save costs compared to using hardened steel.

[@sammoore9120]

Anneal it?