Cast iron surface finishing methods

How would this machine (an old watch makers lathe) have been finished? I imagine it would have been sand cast, and then what, hand filed and sanded? I don't suppose they would have had investment casting? Is there some other method I am not thinking about.

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Thanks

Luke

they have had surface grinders, milling machines and planers for 150 to 200 years now. hand scraping and lapping might be used for final finishing

I'd say a little older then that (just guessing), the very first lathe dates back to 1300BC, in Egypt. I'm sure it wasn't cast iron, but yeah there's some time from then and now to improve. I'd look into Egyptian ways of doing things. You could also look up Jacques De Vaucanson, he was the inventor of the first known all metal slide rest lathe (allegedly). I saw a U tube video on it, quite interesting.

I'm pretty sure that the parts of a watchmaker's lathe that aren't ground or scraped are plated. I think my beautiful 8mm Geneva-pattern Lorch is nickel plated.
The pic doesn't resemble any kind of watchmaker's I've ever seen, maybe a light duty hobbyists lathe?

The exact role of this machine isn't really important, I think it is something like a Schaublin 70 which are used for watch and clock making although they are not an 8mm collet watch makers lathe.

The point is how did they get that surface finish without modern processes such as 3d CNC milling/grinding etc. I am working on a product that is cast iron with non critical curved surfaces and would like to finish it without filling, sanding and painting so a smooth bare iron surface would be a nice option if it could be done without a huge amount of hand work. I suspect the only options would involve either a long time in a CNC milling machine or hours of hand grinding and sanding. Labor was cheap a century ago, not so much today.

whidbey said:

The exact role of this machine isn't really important, I think it is something like a Schaublin 70 which are used for watch and clock making although they are not an 8mm collet watch makers lathe.

The point is how did they get that surface finish without modern processes such as 3d CNC milling/grinding etc. I am working on a product that is cast iron with non critical curved surfaces and would like to finish it without filling, sanding and painting so a smooth bare iron surface would be a nice option if it could be done without a huge amount of hand work. I suspect the only options would involve either a long time in a CNC milling machine or hours of hand grinding and sanding. Labor was cheap a century ago, not so much today.

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(Grey) cast iron is really easy to file but depending on how rough your castings turn out there can be still plenty of work left.
Filing was lot more common back in the day and probably only viable way to smoothen some of those curved surfaces.

If they could make a lathe they could also make a planer
Most if not all of those curved surfaces can be made on a planer using a template in the shape of the curve

Peter

I have seen a copy of a late 19th or early 20th century Rivett catalog that showed pictures of their castings being milled with custom multi-tooth form milling cutters to finish all the pretty curved parts on their lathes. I suppose planers were used for the flat bits. The Rivett catalog also showed how their precision 8 lathe with relieving attachment and milling attachment could make the form cutters. The working surfaces of Rivett bench lathes were hand scraped. I suppose the unscraped surfaces got hand polishing to remove any machining marks. They did not paint the smooth iron on their machines. Rivett lathes stood out because of the polished bare iron all over. They look great until they get rusty.

The other watch lathe companies in Massachusetts and Illinois, etc. finished their castings all over, much as Rivett did. The small watch lathes for use in the front of jewelry stores were almost all nickle plated after the iron was machined and polished. Machines made for use in the watch factories got no decorative finishing unless they were meant to be displayed in a fair or such. Some time around the 1930's, cheaper painted finishes became common and chrome plate replaced nickle in some lathe factories.

Below are pictures of a circa 1850 milling machine in the American Precision Museum. The form cutter is finishing part of the edge of a rifle lock plate, but is much like the cutters that would be used by Rivett and the other lathe makers.

And I show four pictures of a partly machined headstock and tailstock for a circa 1950 Marshall Peerless watch lathe, along with a finished tailstock. The machined surfaces are fairly smooth, requiring minor lapping and polishing. Marshall hand scraped the bottom interface with the lathe bed. I think Marshall had bought the Moseley lathe factory in Elgin, IL, which was founded in 1885. Horace Moseley advertised that he invented the hollow lathe spindle and what we now call a collet. Marshall still used the Moseley brand name on their most expensive lathes in post WWII catalogs.

Larry

Great post Larry.


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For modern techniques to smooth compound curved surfaces like the saddle shape inside the headstock I'd suggest a pneumatic drum sander. I have a Dynabrade 2" diameter drum I use on a large inline air grinder (5/8" spindle).

Those surfaces are expensive though. It's either skilled handwork or invest time and money in specialized machinery.

Thanks for the input guys. The use of form tools makes perfect sense in a pre-cnc world. I guess copying mills could also be used but you do have the same problem of 3d profile milling today in that it is would have been very time consuming with just a ball end mill.

Grinding with belt or drum is probably the most practical modern way but it isn't ideal for many reasons. This really makes investment casting look appealing as while expensive it would provide a nearly finished surface which might actually be cheaper overall.


Luke

whidbey said:

Thanks for the input guys. The use of form tools makes perfect sense in a pre-cnc world. I guess copying mills could also be used but you do have the same problem of 3d profile milling today in that it is would have been very time consuming with just a ball end mill.

Grinding with belt or drum is probably the most practical modern way but it isn't ideal for many reasons. This really makes investment casting look appealing as while expensive it would provide a nearly finished surface which might actually be cheaper overall.


Luke

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You don't have to look very far for the proof of THAT. Most any older carburretor or motorcycle gearcase will do. So will any modern automobile headlamp or tailight assembly.

Minimal finishing needed, but if/as/when a nicer look was wanted, all it took was a series of muslin buffing wheels and perhaps three successive compounds.

Never mind lathes - never really "high-volume" goods, and always able to justify skilled hand fitting and finish for the precision they had to hold.

Look, instead, to the many factories all around the world as produced "Singer" sewing machines. Downright legendary fine finish on cast-iron with superb plating and paints of enduring goodness.

Where there is a need, a way is found. The look of quality is a major part of what customers PAY for, after all. Fail to deliver to that initial perception?

Some other vendor who does do gets the sale. Few will ever know your product may have had better attributes beyond good looks. You are already out of business.

I have many years of experience hand finishing low volume investment iron, steel and bronze castings. They are certainly ready to paint as soon as the mold compound is removed and the sprues cut off. You do have to be aware that the wax model may have voids or seams from being too cool when poured into the master mold. Then there is a second chance for problems if air bubbles are trapped on the wax when the investment is poured around it. I have dealt with lots of holes and warts on these castings. Then there are the wax models that were warped by handling when pulled from the master mold while still soft. Straightening bent cast iron is a tricky job.

Some cast parts can be brought to a polished appearance by tumbling, which is a cheap process compared to sanding and buffing by hand.

Larry

L Vanice said:

Some cast parts can be brought to a polished appearance by tumbling, which is a cheap process compared to sanding and buffing by hand.

Larry

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Thousands per year of investment cast 14K and 18K gold rings and things got exactly that treatment, 3 stages of media, overnight each day, our jewellery manufacturing operation.

Downside is it gets progressively hairier and less useful as size and mass go much above Ladies' "cocktail" rings or lower-density plastic "duplex" electrical outlet bodies!

Long before one reaches the size and mass of even the smaller of split-bed Hardinge lathe castings? The OTHER parts are hammering dings into each other.

There are other neat tricks, though.

Ages before electronics took-over shifting of automatic transmissions, a thick abrasives-laden paste was forced though the intricate passages of "valve body" castings for hydraulically shifted automatic transmissions, cheaply deburring and smoothing the internal passages not reachable by any other means.

Where a challenge arises? Soon arises a clever solution to meet it. "Wetware" thing between the ears guiding delivery between the hands.

I think now I need to find an investment casting foundry in mainland Europe who will work with small orders. The local ones I have found are titanium focused for aerospace and are not going to want to deal with the little guy. (Nor could I afford them) there isn't much call for cast iron on airplanes I bet there are some in Spain that might be a better match.

I think for prototyping 3d printed wax might be the way to go as the set up costs for normal wax molds are expensive. I found a hobby oriented foundry in England but Brexit and high shipping costs make me nervous but perhaps I will get in touch.

whidbey said:

I think now I need to find an investment casting foundry in mainland Europe who will work with small orders. The local ones I have found are titanium focused for aerospace and are not going to want to deal with the little guy. (Nor could I afford them) there isn't much call for cast iron on airplanes I bet there are some in Spain that might be a better match.

I think for prototyping 3d printed wax might be the way to go as the set up costs for normal wax molds are expensive. I found a hobby oriented foundry in England but Brexit and high shipping costs make me nervous but perhaps I will get in touch.

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Centered on Eibar. Basque country. Fly into Bilbao, grab a small Diesel rental, scout West to Cantabria and Asturias.

Bonifacio Echeverria made firearms, his brother Julian started a polytechnical college to train craftsmen. "Star Echeverria" were doing handguns really well with investment casting. "Basque Lawyers" I call my ones. Started with cannons for the Kings of Spain, have also done sewing machines, bicycles, office machines, machine-tools... etc.

About 60% of Spain's "high tech" is in Pays Vasco, Not too different, French-Basque side of the Pyrenees, either - Aerospace, etc.

UK was full of "model engineering" smallholders. I'd worry more that regulations have shut that down and that very few young folk have gone into it. Vanishing asset, IOW. Brexit is less of a factor.

I was also thinking of Eibar, I think there are or at least were many small shops in the area rather than a few big ones such as around Toulouse over in France. I live in the Pyrenees on the French side near the Mediterranean so it is all not too far away. There is also plenty of investment casting around Barcelona (automotive etc) which is closer to me. Time to look for technically minded Spanish speakers in my network I guess as there isn't going to be much English over there.
Luke

whidbey said:

I was also thinking of Eibar, I think there are or at least were many small shops in the area rather than a few big ones such as around Toulouse over in France. I live in the Pyrenees on the French side near the Mediterranean so it is all not too far away. There is also plenty of investment casting around Barcelona (automotive etc) which is closer to me. Time to look for technically minded Spanish speakers in my network I guess as there isn't going to be much English over there.
Luke

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Not a major problem. The two top "western" languages in global commerce are bad English and fair-decent Spanish. Both languages are highly "fault tolerant", y'see. Try THAT with French!

Spanish in business is common even in Brazil. They have to import and export to a whole lot more than just Portugal! Harder to get a Habanero to speak Columbian-grade Spanish than it is to conduct business in "average" Spanish, all over the Americas.

If you grok any two of English, French, or Italian, take you about two weeks with a good audio course to be able to get by just fine in conversational Spanish.

Written is easier yet. Translators work better on Spanish than on most other languages. Spoken isn't hard. Kinda neat to use a language where each vowel or any word has exactly ONE proper sound, not several. Spanish has way less than half the irregular verbs of English, doesn't scatter them about split-up as the Germans do, and uses the same sentence structure as Mandarin Chinese.

Instead of keeping one in suspense, as in "big white.... house, ass, car, elephant"... wotever.. they go straight for "major key" data, as-in "HOUSE, large, white", etc.

Spoken Basque is harder, but they are "try"lingual folks, will apply their tongue to anything if there is any good to come of it!



Med end of the Pyranees? Sounds more Languedoc than Basque?

thermite said:

Med end of the Pyrenees? Sounds more Languedoc than Basque?

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Yes Languedoc-Roussillon, Aude to be more exact but either end of the Spanish Pyrenees are 5 or 6 hours max drive. Something near Barcelona would be much closer as the roads don't go exactly straight to Eibar from here

As for English speaking in Spain I had a rather difficult time getting some special concrete blocks that I ordered from just the other side of the mountains. The driver as far as we could figure out only spoke Catalan, no Spanish, French or English. We figured it out as one does in such situations but concrete blocks are one thing and investment castings are another It is all an adventure and I will figure it out. One runs into fluent english speakers in the strangest places over here, such as the guy who came out to quote the new electrical installation who is very much french but must have grown up in England given his complete fluency.

whidbey said:

Yes Languedoc-Roussillon, Aude to be more exact but either end of the Spanish Pyrenees are 5 or 6 hours max drive. Something near Barcelona would be much closer as the roads don't go exactly straight to Eibar

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LOL! Sheltered life, small countries produce... Eibar is more "vertically distributed" than average, and I doubt ANYTHING in the zone is "straight" for any greater run-length than the barrel of the MIL-SPEC machine-pistols they once sold to Paraguayan marines, et al!



Annnnnd ... "getting there is ALL the fun", interesting route, you avoid the wider motorways. Even so, unless you grew up in WEST By God Virginia, honed skills on Appalachian roads (and CH, Les Diableret, Alto Adige, former East Bloc.. etc..) you do NOT want to drive through Andorra to shorten the trek, either! More to that than the long queue...

Andorran locals fancy themselves rather aggressively competent at dominating mountain roads, find themselves ever-so-slightly disadvantaged when a 2-million-miller who actually enjoys driving the two-lanes (or LESS) all over Italy and North - plus 25 or so OTHER nations - just grins and deals out a lesson or three, rented VW Diesel van/SUV vs arrogant pilot who thot his "pretty face" 7-series Bee Emm Vee was a substitute for Old Age & Treachery!

What was that line from the movie?

"Horse looks good. Let's see about the jockey."

All in good fun. Take the secondary roads. Live a little. enjoy contending with a better class of idiot than those droning along in the Wagons-Lits Blue "sleeper" lanes on the main autoroutes.