Need to order some turcite

I'm scraping on my Springfield lathe. They are relatively soft so not too daunting. The Monarchs have flame hardened
ways of course. I just run the Monarch as is and put up with any inconsistencies encountered.
 
cathead said:
I'm scraping on my Springfield lathe. They are relatively soft so not too daunting. The Monarchs have flame hardened
ways of course. I just run the Monarch as is and put up with any inconsistencies encountered.
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The bed on the MOnarch is flame hardened but the underside of the carriage is not. My carriage V's are hour-glass shaped so I get significant change in the depth of cut when switching from left to right traverse, greater than .005", which I want to correct. Not in any big hurry, I've learned to work with it as is.
 
cathead said:
This is a work on when I feel like it project so it will take a while yet. I'm using the lathe in the process and learning as I go.
I'm using dial indicators against a reference and using a home made scraper with a carbide tip. Basically I'm removing
the material that I can verify that needs to be removed. Later I will have to get a decent straight edge and bluing to finish up.
I have an 18x24 granite surface plate so may be able to get a rough cast iron straight edge and flatten it out.

Several years ago I made a strait edge using steel and scraped it true. I havn't checked it lately to see how flat it might be now.
It might be usable and maybe not. I know that cast iron is more stable but had to see how steel would work out over time.
View attachment 428900The jury its still out on this piece.

View attachment 428901This is my home made scraper with replaceable carbide tip and handle from an old jig saw.

I will make another post when I have made a significant milestone. It's winter up here and the ambient shop temperature
drops off in the cold. Presently the shop temperature stays at 55 to 60 F. without turning on my forced air blowers that
extract heat from circulating boiler water. It gets to the point where I would need to fire harder in the boiler to keep the
shop at 72 F. I added a Modine forced air heater in the water loop so I can have it warm if I need to at the expense of
the woodpile.:concerned:
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I would be interested in knowing how the Steel straight edge is on accuracy now. Thanks. I have thought or making an aluminum frame with cast iron insert or a composite with cast iron insert.
 
ltlvt said:
I would be interested in knowing how the Steel straight edge is on accuracy now. Thanks. I have thought or making an aluminum frame with cast iron insert or a composite with cast iron insert.
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Well, I havn't used it for a while but I am curious as well. To it's credit, it has not seen any large temperature swings so might
still be OK. I need to get out the bluing and surface plate to find out. I will try to do that in the next day or two and post here
again when I find out.

If it turns out to be useless, maybe at least I could cut it up and make book ends or something out of it.:encourage:
 
cathead said:
Well, I havn't used it for a while but I am curious as well. To it's credit, it has not seen any large temperature swings so might
still be OK. I need to get out the bluing and surface plate to find out. I will try to do that in the next day or two and post here
again when I find out.

If it turns out to be useless, maybe at least I could cut it up and make book ends or something out of it.:encourage:
Click to expand...


After a little experimenting with the straight edge on the surface plate, it was determined that the ends are
higher than the middle. I used some Prussian blue on the table and it was clear that the ends were higher
than the middle as the ends were blue with nothing showing up in the middle. So basically that effort was
a failure. Failure and success sort of go hand in hand as if one has no failures, he has no successes either.
So back to the drawing board I guess. The reasonable thing to do would be to get a rough casting of a straight
edge in cast iron and scrape it flat and go from there.
 
cathead said:
After a little experimenting with the straight edge on the surface plate, it was determined that the ends are
higher than the middle. I used some Prussian blue on the table and it was clear that the ends were higher
than the middle as the ends were blue with nothing showing up in the middle. So basically that effort was
a failure. Failure and success sort of go hand in hand as if one has no failures, he has no successes either.
So back to the drawing board I guess. The reasonable thing to do would be to get a rough casting of a straight
edge in cast iron and scrape it flat and go from there.
Click to expand...
Very much thanks for the feedback cathead. I have heard others say that after long periods of non-use they always need to give their cast iron ones a tune up. Watching many of Richard Kings scraping videos I remember him saying his own castings are seasoned for a year before scraping. He also Peens them with a hammer before starting to scrape one for the first time to relieve the stress. I do know that GM Powertrain lets new engine block castings season outdoors for a year before machining them. With today's technology I am surprised that someone has not developed a way to injection mold plastic straight edges. It may be possible but not enough of a market to support the development. In my previous days as a manufacturing manager for AC Spark Plug, we were able to injection mold plastic fuel pump parts to within 2 micron flatness. The base material was mineral reinforced plastic. I guess it all boils down to what a Boeing engineer once told me when they built the first 747 "If you put enough power behind it, you can make a rock fly." In other words, throw enough money at a problem and it will fix itself. LOL Thanks again for the rapid follow up response.
 
ltlvt said:
Watching many of Richard Kings scraping videos I remember him saying his own castings are seasoned for a year before scraping. He also Peens them with a hammer before starting to scrape one for the first time to relieve the stress. I do know that GM Powertrain lets new engine block castings season outdoors for a year before machining them.
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The mistake I made when starting from a rough casting was that I milled off just enough to give a clean surface before scraping. I should have set out to take .050" off after that. Otherwise the surface hardness and stress makes scraping more challenging.
 
cathead said:
Where can one get a rough casting?
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Keith Rucker sells some via vintagemachinery.org. (Look for the OWWM Store section). Also Dennis Foster sells them under the featherweight straight edge on ebay. I believe the featherweight castings can be acquires as either raw casting or pre-machined ready to scrape.
 
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