Getting started in scraping?
I am looking for the absolute basics of getting started in scraping. I sadly can't get out to Seattle for the scraping class that is being advertised now. I have a couple issues of HSM that have parts of the "scraping for the home shop" articles, and I will likely order the older ones. What I am looking for is some sort of videos or articles that I can start with in my garage just learning the basics and the tools to get started. Does anyone have any suggestions?
Hello, I have a DVD I sell on E-Bay. I also recommend the book "Machine Tool Reconditioning" sold by DAPRA Corp and other sources and The Foundations of Mechanical Accuracy sold by Moore Special Tool.
There are a couple of other DVD's out there sold on E-Bay too. I also would be glad to help you via a phone call or Email now and then. I am in Minnesota and will be having a scraping seminar here in the spring and we are also going to have one in Columbia, Missouri this winter or next spring.
I have taught several hundred seminars over the past 30 years as I am a Journeyman Machine Tool Rebuilder. In my seminars I teach machine rebuilding that includes, scraping, leveling, alignment, you bring a small part like a lathe compound and I help you rebuild it. We learn how to scrape gibs, scraping Turcite, etc. I am also always looking for hosts to have a seminar in there shop or garage. I teach between 6 to 8 students per class and will travel to anywhere in world to teach.
In terms of getting supplies for scraping projects.
Next time you are "cross-border" shopping make sure you pick-up either Dykem hi-spot or the Permatex prussian blue (apparently in the USofA you can buy the stuff in Staples, or NAPA or just about any place -- NOT SO in C-eh N-eh D-eh!)
Here Graingers will rip you a new one at triple the US cost plus GST and PST.
I will look into your DVD as well as the machine too reconditioning book which I have heard about before. I would love to host a seminar in my garage once I have it better arranged. How much do you typically charge for a seminar?
Originally Posted by Richard King
I think I actually have a small tube of Prussian blue from an engine rebuilding class I took several years ago, I will have to search through my toolbox and find it.
Originally Posted by bob_s
I usually charge around $200.00 a day per student. You being in Canada will change he price no doubt. I did a class in Hayward WI a couple of years ago and I stayed at the hosts house to cut expenses. I did a seminar recently here in MN and I had 2 men take a one day class, 2 that were there 2 days and 5 that spent 6 days. I furnish all the tools and supplies, but several had their own they brought along. I also recommend a water soluable ink called Canode. I used to use Dykem and It stains everything especially your fingers. You can buy it from Dapra, ES Dyjak, Voit and a couple of others. I also use Canode yellow ink as a red lead substitute. You can see more info about me at Handscraping.com
At the risk of showing my ignorance...
What is scraping?
It is the precision fitting of ways on a machine tools and it provides even oil lubrication film on the ways (also used on Babbit and bronze bushings bearings, etc. Over the years it has been discovered that hand fitting or scraping of the ways is the most precise method so machines wear and function properly. We use a carbide tipped "scraper" that resembles a file or wood chisel. We scrape pockets approximately .0002" deep to form weight carrying high spots and the low spots are for oil. A good scraping job resembles a chess / checker board one spot is high and the next spot is low. Our goal is to get 50% high spots to carry the weight and 50% low spots for oil.
We fit the machine way clearance from .0004" to .001" so oil can squeeze between both sides of the way surfaces so the ways move smoothly and do not wear. We also test the squareness and alignment using levels and gages.
It's a trade, but it is pretty easy to learn if your mechanically inclined and have a good teacher. Scraping is easy but knowing where to scrape and how much to take off is the hard part. I also say in my DVD, start small on a surface plate and then start an easy project like a lathe compound.
Most conventional machines like lathes and mills are scrape to an accuracy of .0002" per 12" and straight edges and jig bore super precision machines are scraped to .00005" per 12". The high spots are classified as High Points per 1 sq. inch and on the conventional machine we try to get 12 to 20 point per inch (PPI) and jig bores / super precision we try to get 38 to 42 PPI If you ever look at the ways of a Bridgeport you see 1/2 moon spots, well those have 2 functions, the main being extra deep oil pockets plus they look nice. they are approx .002" deep.
I was talking to loply and he asked about a Scraping Seminar in the UK sometime, so I just wrote a friend of mine in NE England who owns a used machinery company and asked him is he could host a class next summer. I await his response. So alll who live in the UK pass the word and let me know if your interested in learning to Hand / BIAX power scrape, 1/2 moon flake and learn to repair your machines.
Mechanics that scrape are called Machine tool builders, fitters, or machine rebuilders. I am a Journeyman Machine tool rebuilder and have been teaching scraping for over 30 years for companies like GM, Timken, Cummins, John Deere, worked with several new machine builders in the USA, Europe and Asia; Spinner, Hardinge, Kent, Paragon, Hartford, Sharpe, Chevilier, plus taught several hobbyists and home machine shop owners
Last edited by Richard King; 11-23-2012 at 10:31 AM.
For what it's worth, as a relative new comer who is learning scraping at the moment, I wish I had taken the time to equip myself with a proper sharpening setup earlier on.
I wasted quite a bit of time with carbide blades with the wrong radius and a dull edge, wondering why it wasn't getting me the right results.
It took some time to adapt a diamond grinding wheel to run on my bench grinder and to turn an old gym weight into an iron lap, so I put off doing it. On reflection it would have been wise to do that before touching a piece of metal with a scraper!
Thanks for taking the time to explain that!
That gives me some hope for my beat up lathe!
You have a DVD you say?