Scraping class 2017 in Denmark 

Huch? Schlechte Laune? Nicht vom armen Deutschland reden sondern Wissen weitergeben, ja?

Aber Jammern und Schimpfen ist *immer* leichter als aktiv werden. Besonders im Internet.

Angepinnt, weil der Kommentar so bizzar-lustig ist.

Natürlich gibt es viele Leute in Deutschland die das Schaben beherrschen und natürlich beherrscht man es nicht vollständig nach einem Lehrgang. Letztenendes ist es aber ein erlernbares Handwerk wie alle anderen auch und irgendwo muss man damit anfangen. Um die Bedienung eines Schabers zu lernen ist so ein Kurs genau das richtige. Alles andere, der Großteil des Schabens, das Wissen wie man Maschinen vermisst, richtig tuschiert, falsches Ablesen verhindert, die Lage von Flächen korrigiert und das richtige Vorgehen bei einer Maschine auswählt kann man ohne weiteres von einer sehr Erfahrenen Person per Vortrag lernen. Dabei spielt es nichtmal eine große Rolle ob diese Person direkt gegenüber steht oder ein RU-vid-Video/Instagram-Post macht (von direkten Rückfragen vielleicht mal abgesehen). Es war noch nie so leicht wie heute ein Handwerk zu erlernen, da die Tricks die man früher über Jahrzehnte im Berufsleben gelernt hat per Klick für jeden zugänglich sind - dank Internet! Außerdem sind selbst lange untergegange Handwerkstechniken so gut präserviert wie nie zuvor. Das ist nicht den Bezug zum wesentlichen verlieren, sondern das genaue Gegenteil! Außer natürlich, man möchte unbedingt einem elitären Kreis zugehören und diesen verteidigen, indem man das Wissen möglichst unzugänglich macht.

Scraping the surface!

This Old Tony I just LOL'd. Touché, Tony. Touché.

Very punny

This Old Tony You're really scraping the bottom of the barrel for that pun, Tony.

Robin was there? Why didn't somebody say so! 8^)

I was a very last minute fill in for Jay Killroy who was going to do the class but had to cancel. Sorry.

Do you know if anybody filmed your class, Robin? Would love to see that.

Not that I know of, but I will eventually do a video on it.

Thanks Robin! I will do a followup more on the technical side of scraping and alignment :)

Looking forward to it!

Steve Canny Steve! How fun to see you here. Greetings from a python-docx contributor. I should be getting back to my features.

Hey @wich, fancy meeting you here :)

Yes, I did a teardown video of the rotary table right after I got it.

It's probably someone's dick in a vice.

me too :)

atzkey how could you say that! (Ok I was thinking it)

that was very prominent and did spark my attention

Maybe nothing was there and I did it only pixelate the area to get some attention? ;)

the bearing surface on the base is scraped first to a reference surface, ie a surface plate and then the bearing surface is scraped to the base.

Just as Mr. petersen6 said, I first scraped the housing-bearing-surface flat on the surface plate and used that as a master to blue the rotary-part.

Do the base first, then that becomes the reference for the table.

Duane Dickey scrapping is used in machine rebuilding. Suburban Tools has a video or two where they visit a machine rebuilder, they go over the process.

Nick has gone a bit undercover, but he is - as far as I know - fine.

I believe that flaking is used to create an oil film that suspends the part off of the frictional surface.

scott black it's my understanding that flaking is c 0.002" deep compared to scraping marks of say a tenth of this. I. e, th flaking makes deeper pockets over the surface, but I'm just getting started scraping ...... flaking next few weeks.

Do the base first, then that becomes the reference for the table.

I would have to send assassins out if I didnt ;)

The old boys from the Stasi will help you out for the right price.

250km! 1000km gets you to Turkey!

2500..km

I've underestimated the distances within the EU :)

Stefan Gotteswinter couple of hours run time then 😱😱 I think you had the hammer down there Stefan 😀 please don,t put how many clicks it was , beautiful autobahn you have to drive on makes our pot holed roadworks infested M1 look poor we do a trip south and 30% is in 50mph Ave speed road works poor BMW has to drop down three gears in that section still with 8 gears we got plenty left Great class I had to learn the art to refurbish large electrical contacts and sleeve bearings

250km is nothing.

There has to be something to it - There are industrial processes, calles vibratory stress reliefing, that seem to be based on the same principle :)

Thanks... but reading up on VSR has made me even more dubious.

Seems to me the "ringing" technique could help establish the quality of a casting before starting the scraping process... stresses, inclusions, defects, etc. could be detected acoustically.

It greatly releases stress. In you not the part

It's your problem, that you don't understand basic properties of metals. There are stresses "frozen" inside (from machining, casting, forging, welding, bending, etc.), it's just the way it is. Period. Do your homework. Two basic methods of releasing stresses are: thermal (you heat it up) and mechanical (you shake it). For example in welding it's called "peening". Google that you lazy moron.

I don't know either, but I know that it works, especially while welding cast iron(pain in the ass).

SJWs & Betas Killer Maybe you're the one who needs to read up. Weld peening has zero to do with shock stress relieving like striking a casting. It expands the metal that just shrank as it cooled from welding. Nice try, though.

On the job I retired from we used to use one of these to stress relieve shaft and other material prior to machining. A 6 ft /183 cm shaft with a 1/2"/12mm keyway cut over 75% of its length would bow like a banana if this was not done. www.formula62.com/ Now as to whether hitting a casting with a hammer, can't say. I have to ask if the casting has been "aged" or run through a thermal stress relieving process

I assume the dividing head is weighing quite a lot for putting it in luggage. And driving in Europe is a pleasure in itself, I would prefer driving myself, for example.

Only if I keep it, or money ;)

hahha... you coudn't keep it :P.. i thought for money of course, but i don't think it would be worth for either of us.. it's an emco unimat 3 with some attachments... which means.. too many small surfaces, i guess more of a hassle than practise... and on the other hand, the scrapping would probably cost more than new lathe.. and i'm afraid that you'd throw it away once you see the state of it xD

i sent you an e-mail with a bit more details, please check your spam folder as well

They are rough ground, then lapped flat. Flatness is check with special comparators that operate on the principle that a surface has "hills" above the low spots, and that anything sitting on the slope of a hill will be tilted at an angle that can be measured. Search for surface plate calibration. There are some excellent vids on it.

I might be mistaken, the laps might be precision surfaces.

But similar processes ARE used with metals. So your question doesn't make sense. I mean: grinding, lapping.

My question? I've never seen anyone "scrape" a granite surface.

The laps are precision surfaces, and require periodic maintenance to keep them that way. Keep in mind that an out of calibration surface plate is still very flat, and that granite abrades much faster than a cast iron lap. The lap will stay very flat and any minor variation put into the lap by on surface plate will be removed by the next surface plate. Eventually the lap will acquire a hollow shape that is fixed by lapping it against 2 other plates using the "3 plate method." TBK, it is the same exact process used in labs in extremely high pressure experiments (think metallic hydrogen), only scaled up. microtome blades for some types of sectioning are sharpened by lapping. I have lapped lenses for spectroscopy in a previous job.

I agree it would be hard to put a car onto a surface plate to check how flat the paint is... The principle is simple. Start with something almost flat by grinding or milling, then check it against a perfectly flat surface (a surface plate). Then just scrape off the high spots. Rinse/repeat until it is uniformly flat. There is no machine that exists that can get a surface as flat as hand scraping. The precision machines used for making thing precise are all hand fitted and scrapped.

No, that's the right side of the road

True and wrong. ;-)

It is used to increase the contact area of two sliding surfaces that contact each other.It has nothing to do with auto body work.

You want waves in 2 machined surfaces that rub against because of oil,if everything was flat it would just slip away thnx to a bitch called gravity.this way oil stays in the grooves and helps with friction and reduction in wear.

David Goodrich It takes a bit to wrap your head around. The flat reference surface is the granite plate (or a straightedge that's been scraped to a granite plate). The workpiece is rubbed on the granite to mark high spots with a very thin film of ink. You remove the high spots successively until you get the workpiece into "full" contact with the granite. In most cases, "full" really means about 50% because there must be shallow low spots remaining for lubrication pockets. Hope that helps...?

In body work, you are striving to average things out so that light reflects in a uniform manner. One of the reasons that there are no flat surfaces on a car body, is that it would be commercially impossible to get the paint flat enough to not look terrible. In terms of straightness, even the straightest line on car body is less straight that the most worn out milling machine can make. These folks are measuring straightness to 1/100mm or less.

joshua43214, unless this is a pin-line put on by Mark Court, a coachline painter on a Rolls-Royce. : )

Technically, posting the video is the first :)

Stefan Gotteswinter savage

Childish. Stop it.