Working with Castings

[Mosey]

Well, I am working on my Martin Die Filer kit, and  have a basic casting question.

Is it good form to remove the ragged line around a casting where the 2 pieces of the mold matched up? I'm speaking of areas where there is no machining necessary for the build.
Do you generally grind off these fins with a Dremel/Foredom or other hand grinder?
This would be only so the appearance is neat and clean.
The Martin castings beautiful, like iron ricotta cheese, and a great pleasure to work with. This casting stuff ain't bad.
Thanks,
Mosey   

[Jasonb]

I'll always fettle off the moulding flash and even out any step between the two halves if present. Usually just use files and a dremel in tight to get to parts.

J

[b.lindsey]

Mosey, I think its more a matter of personal preference really. Depends on how pronounced the parting lines are and looking at the pictures you posted after CF, the base casting doesn't look that bad. How you plan to finish a part can make a difference too. Since these are cast iron I am assuming you will probably paint them, might not be the case when working with aluminum castings for example.  Personally if the parting lines are not bad, I would probably leave them or file lightly only to remove any sharp places. Especially in the case of a tool like the die filer, I would want it to look like a casting even after painting and that would include some minor evidence of the parting lines. Just my 2 cents though...ultimately do what makes you happy

Bill

[Mosey]

Bill,
You are right of course, the castings are pretty clean out of the box, so I am just trimming up the small flash at the matchlines. Did it with a Dremel with the fiber metal cutting blade, and it is easy. I want this thing to look good for the pictures (Eric, got that)
Finished first part today, ready for the camera.
3 more castings to go, and a few Bar stock turnings.
Boy am I loving this thing.
Mosey
Here is the Scottish Yoke:
Milling the first register flat





Slitting the yoke on the F1 (Jo?)


By the way, my slitting saws have 5/8" arbor holes and they seem to fit nicely on the arbor with minimal run-out, unlike that other thread about this subject.

[Don1966]

Those are some beautiful casting and I bet they machine pretty good to. Nice start Mosey.

Don

[Mosey]

Don,
You wouldn't need any catsup to eat them! They are nice.
Mosey

[Dave Otto]

Looking good Mosey

Seeing how it is yours you can finish it how ever you like; but as it is a quality shop tool I would like it nicely fettled properly filled, smoothed then a nice coat of paint. 

I'm sure what ever you choose will look great.

Dave

[Mosey]

I hope to make it a proud member of my shop, and will give it  proper finish with auto enamel.
Mosey

[Mosey]

Are the dust and fine gritty swarf from cast iron as abrasive and potentially destructive to the machine as I suspect?
Mosey   

[sshire]

Looking good! I did some light fettling on the main casting parting line of the Dynamo. Just to even the top. I'm keeping the rest basically as-is so it looks like a casting after paint.
Re: the dust. Following One of Tubalcain's videos, I first wrapped aluminum foil around the ways, etc. and topped that with damp paper towels to hold the dust. Easy cleanup and all was protected.

[b.lindsey]

Mosey, they can be for sure and if mixed with oil its even more like an abrasive compound, not to mention harder to clean up.  Mostly, just vacuum up well after working with the cast iron, use a brush to get it out of all the nooks and crannies, and you should be fine. You might want to also check the scroll on you lathe chuck and jaws since some of the fine dust can be sucked up in there also. Good cast iron is a pleasure to work with, but does take some extra cleaning effort.

Bill

[Mosey]

An aspect of the Aciera F1 is it's completely exposed ways for all 3 axes, leaving it subject to swarf getting into the small fissures. Better protect it with a giant dental dam! I will have to do a thorough clean up and lubrication, as I am concerned about damaging those hand scraped slideways.
Mosey

[Tennessee Whiskey]

So Yo Mosey, how's things down Jersey huh? Just got my die filer castings that you stole out from under me at CF and they are beautiful, onlys one problem, they ain't no drawings huh, I talked to Gary, great guy, said he'd send them after NAMES. Since you stole my castings, how about sending me some Taylor's pork roll; you don't need it and I love it on a roll wit some spicy mustard

Whiskey

[Mosey]

You are so bad! I'll send you the drawings, but you wont need them for 6 months with all that other stuff.
Mosey
 

[Tennessee Whiskey]

How bout the pork roll?
Whiskey

[b.lindsey]

I had forgotten you ordered those Eric!!  May need to back off just a tad on the bean and BBQ spice, but I can't complain, you got far more metal at almost half the price compared to the mini-mic.    It's all good though!!! Now if you start making noises about the pending delivery of a maroon Packard, I may start to worry

Bill

[GailinNM]

Now if you start making noises about the pending delivery of a maroon Packard, I may start to worry
Bill

It's called a color chip!
Gail in NM

[b.lindsey]

Hmmmmm...as nice as she is, I don't think even Lou would buy that explanation Gail   

Bill

[Mosey]

Back to the subject, my castings of the die filer seem to have a very hard crust on them. I want to cut through the crust with a minimal depth cut and establish a smooth plane (table top). I also don't want to knock the piece loose from it's clamping to the table.
How do I hold the piece down?
What cutting tool would be best make a smooth flat surface? Flycutter?? Large indexible Face Mill? Carbide inserts?

Keep in mind the mill is medium size, 5/8" shank mill max.
I think I will have to face clamp it (6" x 6"), mill sections roughly, and then flycut for final surface using miteebites.

What do you think of taking off the crust on the belt sander first?
Open for suggestions, thank you.
Mosey   

[Jo]

Heat treat it, then use a hand file to give you some basic clamping points.

Jo

[Mosey]

oooh, thank you. Will do.
Mosey

[Mosey]

Jo,
How long in the oven, what temperature, and I assume air cooling?
Mosey

[Roger B]

I think that Jo generally chucks the bits in the bonfire   

[Jo]

Roger is right  you need temperature far beyond what the domestic oven can provide and you need to heat up slowly and cool down just as slowly 

For small hard spots then a localised heating with a gas torch can work but with a full casting if you have not got a temperature controlled metal workers furnace like Rod's  then you will be forced to use a bonfire like I do.

Jo

[Mosey]

I have buddy across the street with a metal-working shop and foundry who could heat treat it for me if I knew the parameters.
Mosey

[Dave Otto]

Hi Mosey

What I have done in the past is to cook the castings at 1500 degrees F long enough so they are heated clear through. Then shut the furnace off and let it cool over night; don't open the door! Most furnaces have enough insulation they will cool slow enough as not to chill the castings.

I did this with two sets of Little Brother castings and they machined beautifully afterword. I didn't do the flywheel as they were ok.

Dave

[Jasonb]

I thought Martin's annealed all their castings. Is it just a bit of a skin you have or are there actual hard chilled areas that are taking the edge off a HSS tool?

J

[Mosey]

I believe that the castings have a thin, hard skin. I am gradually skimming them down through the skin, and it is slow going, but I expect to get there.
Mosey

[Jo]

Leave it in a bonfire for a day or so

Jo

[Jasonb]

If its just a skin then something like a little hogger will get through that, I think someone sells them in the US.

J

[Mosey]

I skimmed the surface with a 1/2" roughing mill, lots of passes but finally got a cut thru the crusty surface all over the table. Switched to a fly cutter. HSS cutter doesn't cut very well, as it bounces and skids across the surface, so I am using carbide. I have the way locks tight to minimize vibration. Here is where I want a big mill, like a Bridgeport. My mill has Y axis travel of 3-1/2", and my big flycutter is 4" so I still have to make several passes to cover the 6" table. I am getting a decent finish but not smooth as a baby's you know what. Since this is a table that will have hand held parts being  worked on, the imperfections of a thousandth or so don't affect the results, but they do bother me. Maybe some time on Emory paper to further smooth the finish will need to happen.
Mosey..still learning...

[Mosey]

I attacked this problem with new vigor today.
I decided that the flycutter in my lightweight machine is not rigid enough to do the job properly, so I mounted that largest end mill, 1", in the spindle and set the speed to 100 fpm, locked everything tightly and went to work. This setup cuts smoothly and easily.
The only problem remaining is the fact the the machine is limited to 5" in cross-travel where I have a 6" surface to finish. I'm hoping that with care, I can move the vise on the table the extra inch without disturbing the flatness of the final surface.
I am looking for a face mill with shank (5/8") to fit the mill.
Mosey