Small scraping project wanted

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Small scraping project wanted

This topic has 10 replies, 8 voices, and was last updated 19 January 2022 at 14:55 by Ex contributor.

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19 January 2022 at 02:40 #581129
MikeK
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@mikek40713
I've never done any scraping before, but I'd like to do something small this winter. Are there any small projects people would suggest? Something that would not be daunting and would have a use after complete. I was thinking about a gauge to check the flatness of my 12"x18" surface plate, which could start as a 2"x4" plate that I scrape flat? But I'm open to ideas.

-Mike
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19 January 2022 at 02:40 #20579
MikeK
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@mikek40713
19 January 2022 at 06:43 #581138
pgk pgk
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@pgkpgk17461
Keith Rucker at Vintage Machinery did a number of videos on learning to scrape and also sells a 9" camelback straight edge rough casting that needs scraping to be used but cost and postage from the US might be an issue. Ah! Just noticed you are in the US!

pgk
19 January 2022 at 09:22 #581152
Dalboy
Participant
@dalboy
When I was training as a plant mechanic one of the things we had to make was a straight edge which got us to cut with a hacksaw to a line filing straight edges, filing curves and finally using a scraper and surface plate to get the straight edge square and true may seem a simple project but surprising what it taught us.

I still have it now many years after I made it I will one day put it onto the surface plate again just in case it has been damaged after being throw into a tool box and left there for many a year( I know I should have treated it with a lot more respect).

I will try and take a photo of it
19 January 2022 at 12:18 #581178
mechman48
Participant
@mechman48
Mike.go with your first Idea; make up a pair of blocks as gauges which could be used as matched packers later. Scrape them flat to your surface plate as master then scrape them flat to each other & see how close you can match them as a pair.

George.
19 January 2022 at 13:15 #581186
Henry Brown
Participant
@henrybrown95529
I made a small surface plate, approx 6" x 4", as an apprentice and often use it still when I don't want to clear the bits and bobs of my 24" x 18" plate, I'd suggest getting a chunk of CI around the smaller size. I'd suggest stress relieving what ever it is you decide to use.
19 January 2022 at 13:16 #581187
Pete Rimmer
Participant
@peterimmer30576
Posted by MikeK on 19/01/2022 02:40:05:

I've never done any scraping before, but I'd like to do something small this winter. Are there any small projects people would suggest? Something that would not be daunting and would have a use after complete. I was thinking about a gauge to check the flatness of my 12"x18" surface plate, which could start as a 2"x4" plate that I scrape flat? But I'm open to ideas.

-Mike

Mike if you're anywhere near me in Kent I would gladly spare you a couple p of hours to set you on the road. I did this for a guy a couple of weeks ago he was trying to scrape in a small milling machine bed. After a few hours basic tuition he's now getting great results.

One thing though if you want to make a gauge to check your plate what are you going to use to make your gauge with? Again if you were near to me I could check your plate for you no problem.
19 January 2022 at 13:28 #581191
KWIL
Participant
@kwil
Search "whitworth 3 plate method"
19 January 2022 at 14:19 #581199
MikeK
Participant
@mikek40713
Thanks for the great responses, guys.

I didn't know about the Vintage Machinery rough casting…that looks good.

A straight edge is a good idea, and useful. I just saw an article in an old "The Home Shop Machinist" (US pub) showing the making of a machinist level, which would put a small homemade level to good use.

Matched blocks is also good as I actually have no V blocks.

A small surface plate would be great as I'm loathe to haul out my heavy 12x18x3 granite plate.

I don't think I'm anywhere near Kent, unless that is Kent, Ohio. But I'm still not close to that. Thank you for the offer, Pete.
19 January 2022 at 14:28 #581201
MikeK
Participant
@mikek40713
Question about a straight edge…

Since I'm cheap (and broke), if I were to fabricate/weld something out of steel along the lines of Keith Rucker's cast iron straightedge: a) would it be pointless to make it from steel and 2) could I stress relieve it in the kitchen stove? I'll be on the lookout for an old cast iron barbell weight, as well, that I could cut material from. Could *that* be stress relieved in the kitchen stove?
19 January 2022 at 14:55 #581207
Ex contributor
Participant
@mgnbuk
would it be pointless to make it from steel and 2) could I stress relieve it in the kitchen stove?

Steel is not nice to scrape – needs a really sharp edge on the scraper & the swarf comes off as sharp needles that take a lot of digging out of your hands. The fitters at my last employment used flat files ground & finished on a fine oil stone for scraping steel, rather than the carbide scrapers they normally used on cast iron, as the file could be stoned to a sharper edge. The carbide scrapers would skate off the steel rather than cut. They would refinish the edge on the oilstone betwen passes to keep the tool sharp.

How hot does your stove go ? If it could get the fabrication up to red heat, hold it there for a couple of hours then cool slowly give it a go. Previous company used to fabricate in house, but sent the fabs out for "stress relieve, shot blast & prime" before sending on for machining.

I would suggest sticking to cast iron of known provenenance for your trial piece – scraping can be frustrating enough without adding other variables like steel or unknown material from barbel weights.

Nigel B.
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