So you've got a slab or iron. Now what? *LINK*

So, you're telling me

Bill Houghton, Sebastopol, CA

we can forgive Joseph Whitworth for his threads (or, more accurately, for what the British did with the heads on the bolts using his threads)?

Your post is one I'm going to need to read closely, probably with that sense of impending doom, as I hear, in the distance, the siren voices of yet another project list/skill set. Quick, where's the beeswax?

Connelly book for download

Al Goldstein

Looks like the Connelly book can be downloaded for free. Check this out.

http://www.filestube.com/3c34b456e89a6ec503ea,g/Machine-Tool-Reconditioning-and-Applications-of-Hand-Scraping.html

I wasn't aware... *LINK*

David Barnett

... Machine Tool Reconditioning had passed into the public domain. I do know that it's still offered in a hard print edition. Because this site states:

"Password recovery: RAR Magic Password Cracker"

I'd be dubious, but having a book in print does not necessarily mean the publishing rights are wholly owned by that enterprise. If it's all aboveboard -- and it may very well be, it'd sure be a great online resource. Terrific book.


Machine Tool Publications

I got a strange, very strange malware response...

Doug Trembath

and Norton had just run an error-free scan minutes before...????

Scared me, coming from WC...

Doug Trembath

Re: Connelly book for download

Pam Niedermayer - Austin, TX

I downloaded the file (boy, that site makes me want to pay just to avoid it), but it's got a weird file type (djvu) that my applications don't recognize; so all that for nothing. But thanks anyhow, Al, the book is worth the try.

Pam

Re: Connelly book for download *LINK*

Phil Joines

It's an open format for scanned documents.


http://en.wikipedia.org/wiki/DjVu

Re: Connelly book for download

Pam Niedermayer - Austin, TX

Thanks, Phil, downloaded MacDjVu a few minutes ago. Hope it works as advertised since pdf online is too s-l-o-w.

Pam

Re: Connelly book for download *LINK*

craigd

Not a site that inspires confidence but the file is good and the scan is good (other than the photos). Might even be legal (copyright 1957). I'm using WinDjView to read it, which is freeware (windows or mac) you can get from


WinDjView

Re: So you've got a slab or iron. Now what?

TomD

Fascinating stuff. But... It's like a digital watch. Just because it's there, doesn't mean we have an all of a sudden need for split second accuracy. I'm loving it, because I have a lot of that kind of machinist and accurate restoration stuff in my shop. Carbide scrapers, granite surface plates, camel-back straight edges and wedges, a cast iron surface plate, the blue... But just because someone needs these accurate references and all of a sudden we are using cast iron surfaces, doesn't mean the average guy needs this stuff. It would be cool to have a pyramid diagram of all this stuff with relevant accuracy as one descends from reference to finished tasks. Even in the machinist community you get guys wasting time with levels of accuracy that aren't in the cards for what they are doing.

I'm thinking the perfect machine for this stuff is the shaper. The surface is smooth without swirl, and more than accrate enough for anything one might need. There are a lot of these machines out there, and they aren't used all that heavily. A local online ad might get you some help.

outube.com/watch?v=5hY6UGMUG3k

Re: So you've got a slab or iron. Now what?

TomD

Hand scraping is for creating accurate surfaces for mating surfaces of machine tools. With these surfaces it is not desirable to have 100% bearing, I forget the number but a half or 1/3rd is what comes to mind. I would have though 100% surfaces of lower accuracy would be more desirable than low contact surfaces of higher accuracy.

Scraping isn't only for bearing surfaces

David Barnett

"Hand scraping is for creating accurate surfaces for mating surfaces of machine tools."

Yes, but it's not only for that. When scraping trying surfaces, for surface plates, laps, and gage blocks, scraped surfaces may approach 100% of bearing. On gages, scraping is often used to bring a lapped surface into tolerance, whether to initial standard or through maintenance calibration. In fact, on page 4 of MTR (the printed version), it is mentioned that 75% of bearing is often specified for mating surfaces, so I'm not sure where your lower numbers originate, although I'm sure they're entirely viable for non-truing reference surfaces.

I do know I scraped my first machine tool, a small antique Conn. River Valley lathe, to about 75% and it was a thoroughly addicting experience.

You're just being reasonable, Tom.

David Barnett

"But just because someone needs these accurate references and all of a sudden we are using cast iron surfaces, doesn't mean the average guy needs this stuff."

You're absolutely right, Tom. I'll give you that. And you don't really need to scrape a lap flat, but it's fun to learn and pretty cheap and not too noisy and you get to use another truly simple hand tool. Besides, how many of us hand tool sorts don't have a stationary power tool bed just begging to be scraped? Okay, maybe not. But add one more level of refinement. learn to frost, and the sides on your Bailey and Bedrocks can have that faux-florentined look!

Re: You're just being reasonable, Tom.

TomD

Well one thing I would grant is that if you wanted to learn this stuff, this would be a great practice piece to do it on. Right size etc... Just so long as the people doing this stuff are aware of what it exists for.

The faux part might be a little trying. I like to keep stuff where it is supposed to be for the purposes it is intended for, though I could imagine a utility to these kinds of surfaces on planes. It's like this guy who makes these guitars with left and right soundboard segments in different woods. He has a little ying yang motif of wood so that there is one dovetail in either side of the center line of the other wood. Visually very pleasing, but every time I see it, it bothers me that the dovetails are made of side grain, and are actually weakening the joint.

I have to rescrape the saddle of my mill some day, so I expect to get enough of this stuff to keep me busy without inventing it.

I suppose one cool thing would be if more people realized where the accuracy of machines actually comes from.

Re: So you've got a slab or iron. Now what?

bugbear

I would have though 100% surfaces of lower accuracy

I'm not sure what even means. In scraping, you never see 100% coverage of the marking compound, because that simply means your marking compound layer is thicker than the largest error in your workpiece.

The normal term for such a layer of marking compound is "too thick"

Scraping (or more generally, metal cutting to a reference) is an excellent way to flatten a workpiece by hand (lacking surface grinders, planers or milling machines), and need not be done to excess precision.

BugBear

Re: So you've got a slab or iron. Now what?

TomD

I'm all for that, my only concern is the lap aspect. Scraping a plane sole, sounds like a good idea, at least as far as the outcome is concerned. Even irregularity in the surface at the mouth would be like complaining about wood grain texture on a wooden plane. My concern in this thread's context is what happens when the diamond particles are scattered over the surface. How much falls below the horizon and isn't cutting. I haven't thought about particle size. Seems to me they would get lost, but maybe someone will say the granularity isn't a problem in the particular case. I just think a shaper/planer would leave a near perfect surface that is very smooth for a good seat for the diamond, and more than sufficient accuracy.

Just not getting the naysayers

Bob Hackett

I`m just not seeing how investing in over a half ton of machine tool(a planer) is a more viable answer than than scraping.Scraping involves a reference surface,bluing and a scraper(hand tool).You can scrape to nearly any range of accuracy you desire and the technique can be used on anything from a block plane to a cylinder head from the engine of a locomotive once it`s understood(and the learning curve ain`t that steep,let me tell you).

Thom`s probably advocating handing off your problem to someone who already owns a planer but why?David has pointed toward a simple,enjoyable,accurate and cheap process that can be done at home and is applicable to many things in a typical WWing shop.

The answer is NOT finding a new buddy with a planer.I can teach 100 people how to scrape and send all of them home with a CI plate that is far more accurate than they really need before you can locate,call,schedule a time and then drop off your piece to be machined.

Read the info and you tell me what you`d rather do,locate a planer or get to scraping.Remember,we do own other metal tools that need surfaces that require some degree of accuracy and scraping can be used there too.

BTW-I will go out on a limb and say that a vertical mill with a fly cutter will leave a scratch pattern(uni-directional,semi-circular) that is more beneficial to what we are trying to do with loose diamonds than the straight pattern of a planer or the random arcs of blanchard grinding.Something else to think about while we`re running off the edge of reason.

For those of you wondering why you don`t want to grind or otherwise abrade a CI into flat.You don`t want to use abrasives for the same reason you don`t want to try to use a single CI plate for multiple sizes of diamond,contamination.Whatever abrasive you use to grind that plate flat will contaminate the plate with the grit from the process.Good luck getting all of that cleaned off your new plate.

Files will get you plenty close *LINK*

David Barnett

"Whatever abrasive you use to grind that plate flat will contaminate the plate with the grit from the process.Good luck getting all of that cleaned off your new plate."

Right. Filing the way to go, here, and it's another simple hand tool bringing with it all the fun of learning a skill and improving it. If you need to flatten something wider than a standard file can reach and you don't have a cranked file, yeah, consider other means, perhaps -- maybe even coarse scraping. But for plane soles and laps, files are just the thing.

Also, plane soles don't usually require extensive work and certainly not a high number of bearing points per inch. What's more, you can use files or abrasives (it's not a lap) to get it close to where you might want to scrape. Joel M. has a nice article on scraping plane soles to flatness. Note that the title might make it sound as if you're flattening a wooden sole. It is about metal soles, I assure you. The article also tells you how to know when you're done.


Flattening plane soles

Re: Steady On

TomD

Who's being a naysayer? I'm just wondering why an uneven surface is preferable to a flat one. Or even why one needs to touch something like the average table saw surface at all, if it is intact. I just asked a question. I may have my own answer though, because I think it may be the case that the piece of iron I am using is actually a practice piece the machine repair shop I got it at had for their "apprentices". But it is an extremely smooth surface not frosted, looks like a piece of marble counter top smoothness wise. Seems to work great, but I guess I don't know what i might be missing...

I guess I may need to get my scraping video out, but my recollection is that the tool marks have some depth, so the surface will have hollows between the points, though that could be a good thing, I was assuming not, to which an actual answer would be beneficial.

What are you recommending for tools etc... My scraping stuff cost a fortune, where it not for the kind consideration, and probably frugal sense of pricing that the retiring machinist at the repair shop had. I got a ton of carbide scrapers, reference surfaces, carbide wheel for a few hundred. Wasn't free though.

Also I guess, as a non-machinist as far as my schooling is concerned, I would be curious what the machinists think the purpose of all this is. My feeling is they think machine surfaces are something worth producing. That the hand work is to make the machine surfaces possible, not something generally regarded as necessary for secondary uses. If they thought that there would be more power scraping and flaking machines. For instance a shaper could easily power flake or scrape. I would wonder why I don't see these surfaces on laps themselves. I don't mind people knocking themselves out, for the healthy exercise, but I would like to know whether their efforts are sensible in the big picture. Sure if all you have is a file you could scrape with that where something else was not available. I just want to know what the utility of these efforts is.

A clarification

David Barnett

Perhaps there's confusion over several uses for scraping. High-level gage making differs, for example, from machine tool bearing surfaces and mating surfaces on other precision machines, such as highly accurate x-ray machines used to treat tumors.

Making a plate for abrasive lapping, or scraping to flatten a plane sole should be considered somewhat differently than the above examples. These are not gages nor mating surfaces and can successfully be undertaken by non-machinists.

"My scraping stuff cost a fortune..."

An old file with a handle (or a cheap imported scraper from MSC or Enco), a cheap surface plate, slab of glass or flat tablesaw top will do for the above applications.

"Also I guess, as a non-machinist as far as my schooling is concerned, I would be curious what the machinists think the purpose of all this is. My feeling is they think machine surfaces are something worth producing."

I guess that would depend on the machinist, but I can tell you hand scraping is held in very high regard by those who teach it and companies who use it.

Whoever wrote this entry for "Hand Scraper" in Wikipedia sums up the general consensus as I understand it:

"A surface prepared in this way is superior in overall accuracy to any prepared by machining or grinding operations, although lapping can equal or exceed it over small distances.

...

Scraping is the only method for producing an original set of flat surfaces from which one can transfer that accuracy through to other surfaces by means of grinding. Lapping and grinding do not achieve the long distance flatness scraping can, as they act on the entire surface rather than local high or low spots."

"That the hand work is to make the machine surfaces possible, not something generally regarded as necessary for secondary uses."

This might seem so to some machinists, but to those who employ Whitworth's principles and techniques to make gages, machine mating and bearing surfaces, while the eventual goal of such refinement, might well, to those who work at the very highest level, seem secondary.

Investment vs return

Bob Hackett

Who am I to discourage someone from emptying their wallet if they feel a need to?Spend away if that is your desire!

Let me tell you how I would conduct the scraping class for those hundred people.

I would collect 100 worn out old files from either the dump or various other local sources.I`d get `em for free but even if I was under the gun and bought them as scrap from the local shipyard it`d be about $10 and $5 in gas so $15 total.

Id dig a hole and short trench in the ground and lay a pipe in the trench so it could blow air into the hole which would hold a fire fueled by scraps from the nearest construction site.Even if I bought a used hair drier rather than borrowing SWMBO`s the thrift store would only charge me $5 max,so we`re us to $20. I`d cut a bunch of rounds from the nearest storm toppled tree and drag them in as personal work benches,maybe lag bolt an old door across some of them and bolt a couple of borrowed vises and grinders to the new work bench.Door from dump,bolts from stash=Zero investment and both can be reclaimed so nothing lost here.

Once the dull files are hot filed by the not so dull files(if they`re all dull I`d soak the best in vinegar or battery acid to sharpen them enough to get by ) after being heated in the "forge pit". I`d reheat and bend them then heat treat by bringing them to non-magnetic heat(old speaker magnet from the dump) and quench them in old cooking oil discarded by the local fast food joint.They normally pay to get rid of it so they give it to me free.

Grind the end of your new scraper/former file and temper in my $10 toaster oven from the thrift shop and you`re ready to hone and get to work.

I`d probably let them fight over who`s going to keep the stumps but I`d give first dibs to those who volunteered to fill in the pit and help me load my truck with whatever I was taking back home,including cleaning and loading my CI reference plate(which I paid less than $40 for)and ink roller.

Even counting the toaster oven (which owes me nothing after more than 5 years of service) and a large tube of bluing I still have less than $50 in holding the class for 100.They all go home with a flat CI plate,a scraper, and skills.

The CI they can either bring themselves or I`d reflect that in the class fee.

Seeing as how there are always jack rabbits and over achievers in any group I`d also bring some bits of HSS and carbide and gear like a Bernzomatic torch and brazing rod and refractory bricks to show them how to make HSS/carbide tipped scrapers too.I`d charge accordingly for those extra materials.

Oh,and diamond to sharpen the "high tech" scrapers with.

Gotta have DIAMOND!!

Re: Connelly book for download

Pam Niedermayer - Austin, TX

Thanks, Craig, I downloaded the Mac version, which seems to work fine. It read the file, and seems much faster than pdf, I like it.

Pam

Re: Investment vs return

Pam Niedermayer - Austin, TX

Seems very resourceful, Bob, until you get to the last line about the CI reference plate. If the average person gets such a plate, where's the need for scraping. For this diamond process, you only need the one plate for 1 micron paste. Right?

Pam

Re: Investment vs return

Bob Hackett

You do need only one plate to sharpen as I do.

What the reference plate was being used for in my example was to roll out the bluing on so the folks in the class who were scraping their own plates would have a way to check their progress.

I could just as well have used a thick piece of float glass on plywood for a reference plate but I already have the CI plate.

Re: Investment vs return

Pam Niedermayer - Austin, TX

Sure, but the float glass and plywood would cost about $40 anyhow, so why not just buy the $40 (sounds cheap to me) reference plate?

Pam