Self teaching scraping

komatias said:
Getting taught how to do it is fine, if you can find the person to teach you and they have the time and patience.

My personal experience is that you can do it but it will take a long time and you will not know what you are doing until it clicks. When it does, as Richard mentioned in his "scraping help" post, you hit 20 spots per inch accidentally.

What you need to ask yourself is: What do I want to achieve? Scraping for scraping's sake is just not worth the effort or pain. Especially manual scraping.

As with most machining it requires equipment so you can't just buy a toolsteel scraper and get to work. I wanted to get a crappy mill true flat, and parallel. To that end I got a bunch of measuring equipment, granite tables, blades, 0.002mm resolution dial gauges and even a Biax. With the help of Richard, Eric and others I think I now can scrape and align good enough for what I need.

If you can grind or mill sections of the machine you want to correct then do it. Anything above 0.10mm is right pain to rectify unless you have all day/week/month.

Otherwise, I do find that scraping is therapeutic. You can see the results of your labor albeit in spots.
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Your proof it can be done from reading books, and online. I believe we started to help on the other site must have been 6 months ago? Others helped you too, Forrest Addy I think started to try to help, others guy over there...and then me.....I try to get over to the other sites and must have lost track of that thread as I spend 90% of my time here now. Less Stressful Hobby Machinist is why I am here and helping where I can. The other sites allow angry people and I can't handle that anymore. My blood pressure is so much lower on here.

Anyway you are proof it can be done, trial and error. Everyone should congratulate you as you have had a impaired arm from surgery right?

The secret to scraping is patience and small devided scrape marks, pressure, stoning, hinge...a lot to learn and remember. I think K ( I can't remember your first name) had several issues we had to solve online. My students had me standing behind them, helping hold the scraper..I get some odd looks when I stand close and help move the scraper as they are holding it at the same time...LOL. your scrape marks we saw via your photo's were touching at first, chatter which he solved himself by slowing the one speed scraper with a reostat and after trying to send him pictures and explaining, we all helped here...he finally he got it, plus buying the biax helped with it's consistant length of stroke and slowing it down.

For years you have heard scraping is a lost art and it takes years to learn how. I disagree and you all have helped prove the nay-sayers wrong. I always say it's easy to learn t scrape, but knowing where to scrape and how much to take off is the skill that takes a long time to learn. I have over 20,000 students now over 30 years of training and you hobbyist have been some of the memorial ones. Teaching in Turkey and Taiwan are at the top of the list too.

I quess K you qualify as one of the kids as you learned the hard way. I am proud of your scraping. It took you months and my other kids learned in days. But you learned, that's what counts. Now it is your turn to help others...I ask all my kids to teach others , pass on my knowledge, now our knowledge. Thank you and to all my students as you make me so proud! Rich
 
I taught myself to scrape with the help of Nick Mueller, and some old scans of machine rebuilding texts. My comments on the experience are

1) It's not that hard
2) It takes a lot of time, especially when you first start
3) You will make things worse before you make them better (so start on something non-critical)
4) If I had known about Richards video when I started, I would have purchased it straight away. Nick Muellers videos are great, but I found I had to watch them all a couple times, and go try some things. Then, when I was having trouble, go watch them all again.

I also thing there are some things about scraping that can't be taught, you just have to do it till you "get it". The hardest is figuring out when to stop roughing, and when to start finishing. If you start trying to finish too soon, you will be there FOREVER.

The first thing I scraped was the saddle of my mini lathe. I used the ground ways as a reference, and made my own scraper out of an old file; and it worked fine on the super soft cast iron this thing was made of. It took me 3 or 4 days to do it (working about 2 hours in the evenings). The first day and a half, I made things worse, and then things started getting better.

After that I tried scraping in a piece of durabar for making a dovetail prism. That old file didn't cut it (haha). I purchased an anderson scraper, and some carbide blanks. Silver brazed the carbide blanks to a mild steel handle and made a very serviceable scraper. Works nearly as well as the Anderson.

There were certainly times when it would have been useful to have someone to point me in the right direction, but I made do without (because I had no other option at the time ;)
 
Thanks everyone for all the good input. I want to learn scraping because I eventually want to fully restore a bridgeport mill,as well as a few other machine tools. I just want to learn how to really do it the RIGHT way insted of the way I usually do things lol. So from reading everyones post you guys seem to think that learning from a skilled instructor is the best,is that right?
 
robert1352 said:
Thanks everyone for all the good input. I want to learn scraping because I eventually want to fully restore a bridgeport mill,as well as a few other machine tools. I just want to learn how to really do it the RIGHT way insted of the way I usually do things lol. So from reading everyones post you guys seem to think that learning from a skilled instructor is the best,is that right?
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Where are you from, you don't say in your profile where you're from? May help if you live near one of my students and they could help you.

Or if you have a nice work shop maybe you could "Host" a class and we can have a class in your shop. Basically all we need is a granite surface plate, some work benches, climate control, a bathroom, good lighting and rm for 8 to 10 students. If you have a lathe we will align / level it, a mill and we can scrape a bad gib....One this the Host is free, accept they need to help. Plus I guarantee you will know how to scrape after the class.
Have a nice weekend all. Rich
 
Back in the 60s I wanted to repair and rebuild machinery for my shop to be; I was serving a machinist's apprenticeship, and found the book "Machine Tool Reconditioning", and this got me started and I did achieve the goal. I now wish that I had the opportunity to attend Richard King's excellent scraping class a lot sooner than I did, as it would have saved me so much TIME and EFFORT, (equal parts of both) and would have greatly enhanced the quality of the work that I did on my original machines, some of which served until I finally retired after over a span of nearly fifty years in the trade.
In short, Richard's classes are well worth the investment in time and money; you really can't get the feel of it from a book, to say nothing of the knowledge attained by the one on one style of instruction.
 
No i'm sorry I dont have a place large enough to host a class,I guess the best thing is to try to get into one of the scraping classes the nest time they are held in Georgia. Thanks everyone for the advice and encouragement.Robert.
 
I just watched Rich's DVD on scraping. Very, very informative and a well made video. Good job, Rich. I know how hard it is to speak clearly and to the point while trying to concentrate on a task at hand. It doesn't seem as hard on the hands as what I had in mind but do see a lot of opportunity to get real stiff-bodied if you don't stretch-out and limber up once in a while. Also, I think you have to remember to take good breaths as that kind of focused work with tightened-up muscles tends to encourage extended periods of shallow breathing. You probably think I'm crazy for thinking of these kinds of things but, having damaged myself in uncountable ways, these are the first things I tend to think of...

Anyhow, I'd like to give it a try and will sometime. Right now, I'm in the process of making a dedicated table for the granite block. It's getting used enough to warrant a permanent and dedicated place of it's own.

I am curious though about scraping... Is it possible to scrape hardened surfaces? Just curious (and don't worry, I have no plans of carving-up any of my equipment).

Ray
 
I learned to scrape from my dad at a early age. At 12 years old, scraping small steel plates flat to each other using a scraper made from a power hacksaw blade with a old square chip breaker brazed to the end of the blade. My blade sharpener was a worn out diamond grinding wheel mounted on a bench grinder. Bedside reading was a copy of Connally's book. And I still have that book! I didn't get my real start in scraping and fitting until 16 or 17 years old. Dad bought a old wore out No. 3 B & S universal horizontal mill for me to rebuild. What a learning experience! Dad borrowed a cast iron surface plate and a couple of straight edges from where he worked, (Left over from Lehmann Machine Co. that the company he worked for at the time bought out for their hollow spindle lathes) and a Biax power scraper. What a life saver!
I don't do scraping for a living, just a hobby. I've rebuilt/reconditioned several lathes, mills, over the last 30 years for myself. My current project is a 20" Standard Duty Lodge & Shipley Gap Bed lathe. Four years and still a lot of work to be done!
I don't claim to be an expert at scraping and fitting, not sure that I have graduated from a novices level yet! Every time I do something, I learn something new. Some of my scraping and fitting, I think "luck" has help me through it. If I get the chance to attend one of Richard's classes in the future, I will. It'll have to be held somewhere here in South Texas, Houston, San Antonio, Austin. I'll have to quit spending my money on tools and save enough for Richard's class. Meantime, I've been wanting to purchase one of his CD. One less tool purchase will pay for it!

Ken
 
I am curious though about scraping... Is it possible to scrape hardened surfaces? Just curious (and don't worry, I have no plans of carving-up any of my equipment).

Ray[/QUOTE]

Ray, the cutters we used in class cut cast like butter.
My South Bend cross slide base yielded easily to carbide, i have no idea what hardness it is though.
the scraper tips are generally soldered or brazed carbide. they were sharpened with diamond tools.
if carbide can cut it, i'll bet you can scrape it....up to a point,i'll bet.
i'm sure grinding would be a better option in most cases.
 
Ulma Doctor

The cast iron in the old South Bend lathes are rather soft. I found that out too on my 9" SBL.

You can scrape harden metal or harden cast iron. Your scraping tools dull rather quickly. That's why most ways that are harden are ground to perfection and your slides scraped and fitted to the H & G ways.

Ken
 
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