A machinist friend claims hand scraping isn't just a dying art around here, it's extinct. Well I looked at the general description and thought "How hard can it be?" Famous last words, I know...
Well, I'm not saying I've mastered the art after a few hours, but I do find it strangely fun and compelling. Seems like good'ol Withworth fathered the technique of scraping three surfaces together, so I figured I'd start by walking it the steps of a true giant. Are there anybody here that know their stuff when it comes to scraping? I need a few good online hints and pointers to get me started, books are easier to buy when you have a rudimentary understanding of the topic...
SemiOT: Any scrapers here (general machining)
Re: SemiOT: Any scrapers here (general machining)
No, but I keep telling myself that one day I will dive into learning the art, so I have been reading a bit here and there.
This book is referenced often - Machine Tool Reconditioning and Applications of Hand Scraping by Connelly
Practical Machinist and Home Shop Machinist are excellent sites.
Any posts by a fellow named Forrest Addy are top notch.
This book is referenced often - Machine Tool Reconditioning and Applications of Hand Scraping by Connelly
Practical Machinist and Home Shop Machinist are excellent sites.
Any posts by a fellow named Forrest Addy are top notch.
- Enfield577
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Re: SemiOT: Any scrapers here (general machining)
I did it many years ago during my apprenticeship.
I remember it being along process and important not to take too much material of, i.e. a few scrapes and recheck
I remember it being along process and important not to take too much material of, i.e. a few scrapes and recheck
Of all the things I've lost it's my mind I miss the most
Re: SemiOT: Any scrapers here (general machining)
Thanks, seems this one is available as a free e-book. Perfect for my old Sony Reader.JohnK454 wrote:Machine Tool Reconditioning and Applications of Hand Scraping by Connelly
I know, it's all those bastards at PM that planted the seed in my head.Practical Machinist and Home Shop Machinist are excellent sites.
- BeerWolf
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Re: SemiOT: Any scrapers here (general machining)
I scrape a bit.
The key is "take it nice and easy".
I gouged the work a few times before i figured it out.
You REALLY don't want to do that, trust me.
The key is "take it nice and easy".
I gouged the work a few times before i figured it out.
You REALLY don't want to do that, trust me.
Don't it always seem to go, that you don't know what you got 'til it's gone?
Re: SemiOT: Any scrapers here (general machining)
I know, I always thought of it as an obscure and redundant technique when it is in fact the very foundation of accurate machining.Dr.K wrote:It's a skill I never even knew existed
Re: SemiOT: Any scrapers here (general machining)
For the past year or two, the Home Shop Machinist magazine has been running a series of articles about hand scraping and how to make the tools. That would be a good source of information. Here's the link to their web site: https://secure.villagepress.com/store/i ... /group/130
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Re: SemiOT: Any scrapers here (general machining)
There is nothing more beautiful than a properly scraped way. Looks like fish scales.
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Re: SemiOT: Any scrapers here (general machining)
I'm still figuring out how the h*ck they manage that nice even pattern. Removing metal by scraping isn't hard to do, making it look like something other than what a chimp with a rock could produce is slightly harder
- Enfield577
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Re: SemiOT: Any scrapers here (general machining)
I think that just comes down to lots of practice, just making evenly spaced cuts by handFulmen wrote:I'm still figuring out how the h*ck they manage that nice even pattern. Removing metal by scraping isn't hard to do, making it look like something other than what a chimp with a rock could produce is slightly harder
With a lot of work maybe you could get it to look like a well trained chimp
Of all the things I've lost it's my mind I miss the most
Re: SemiOT: Any scrapers here (general machining)
I've done a bit. I went to Robert King's scraping school up in Minneappolis. It was a week long and very worth it.
He's considered one of the best scrappers in the world and travels all over the place.
He has a shop where he scrapes machines. It was his dad that invented and pattented the Kingsberry Thrust bearing used by ships and electrical turbines around the world.
A very interesting guy to talk to.
He's considered one of the best scrappers in the world and travels all over the place.
He has a shop where he scrapes machines. It was his dad that invented and pattented the Kingsberry Thrust bearing used by ships and electrical turbines around the world.
A very interesting guy to talk to.
- daviscustom
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Re: SemiOT: Any scrapers here (general machining)
The shop I work in has one guy that does all the scraping on the gundrills and rifling machines we build. I have never done it, but I have always been curious. They are getting ready to shuffle his work station next to mine so I hope to be getting a better understanding of the process. I tend to gravitate towards handwork anyway so I have a natural weakness for a process that can be done by hand and achieve ultra-high accuracy.
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Re: SemiOT: Any scrapers here (general machining)
I scored a proper 8" scraper today for less than 10 bucks, my local dealer had one that had been lying around for at least 6 years so I got it cheap. They sell car restoration equipment and hobby machine tools, but this was the first request for a scraper they've ever had.
I now get the impression that this can't be too hard all things considering, so I'm just waiting for the big surprises to slam be from behind when I least expect it
I now get the impression that this can't be too hard all things considering, so I'm just waiting for the big surprises to slam be from behind when I least expect it
- BeerWolf
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Re: SemiOT: Any scrapers here (general machining)
Trust me when I say that you don't want to try anything important until you've been doing it awhile.
Practice on junk parts or just pieces of steel.
Because this is one of those things that can only be learned by doing it.
I scrapped a few things I meant to scrape.
Practice on junk parts or just pieces of steel.
Because this is one of those things that can only be learned by doing it.
I scrapped a few things I meant to scrape.
Don't it always seem to go, that you don't know what you got 'til it's gone?
Re: SemiOT: Any scrapers here (general machining)
Don't worry, I'm still working on a few pieces of scrap. I did take a looong look at my tailstock yesterday, but managed to tear myself away before doing any damage. I did do a few cuts on my bench vice, and the difference between cast iron and the mild steel I've been practicing on was like night and day. So next will be to find something cast I can practice on...
Here's my progress so far:
It's hard to get a decent surface in mild steel, the cuts end up long, narrow and shallow. I also get a lot of chatter. My few cuts on my vice was a lot better, I was instantly able to cut patches with roughly equal width/length.
Here's my progress so far:
It's hard to get a decent surface in mild steel, the cuts end up long, narrow and shallow. I also get a lot of chatter. My few cuts on my vice was a lot better, I was instantly able to cut patches with roughly equal width/length.
Re: SemiOT: Any scrapers here (general machining)
AFAIK mild steel is not a candidate to be scraped. Only fine-grained cast iron, like Meehanite, can be correctly scraped.
For some beautiful examples, look to U.K amateur-made small machines, like cutter-grinders, "Tom Sr." mills, etc. Those old boys in the U.K. pre and post WW2 did some nice work. Then, the hobby mostly died there, victim of mass media entertainment and the like, just like the USA.
For some beautiful examples, look to U.K amateur-made small machines, like cutter-grinders, "Tom Sr." mills, etc. Those old boys in the U.K. pre and post WW2 did some nice work. Then, the hobby mostly died there, victim of mass media entertainment and the like, just like the USA.
Re: SemiOT: Any scrapers here (general machining)
Not sure if I agree with you there. Scraping is just another form of metal cutting, so why not? It may not be the optimum material to work with, but I'm scraping it as we speak and it is slowly getting flatter.
Re: SemiOT: Any scrapers here (general machining)
I work the same place DavisCustom works, it's amazzing to see what they can do they will surface grind a way base and then ink it up then Gerald goes to work on it.
The one that gets me is when he does a gun drill spindle he will scrape .0002 taper in the spindle housing base to account for drill bit drop before the bit goes into the drill guide.
I will try to get some pictures of his work and get them posted up for you all to see.
The one that gets me is when he does a gun drill spindle he will scrape .0002 taper in the spindle housing base to account for drill bit drop before the bit goes into the drill guide.
I will try to get some pictures of his work and get them posted up for you all to see.