flattening it OLD SKOOL

[drysdam]

I'm new to model engineering and machining in general. In fact, I don't even have a lathe yet (it's on backorder). My first engine project is going to be the LMS oscillator. Here's the thing: I don't have a mill and won't until I save my pennies for it. Both the instructions and the video by Swarfrat say "if you don't have a mill, you can just file it" but don't say how.

For a while, I imagined making do with the lathe. But it doesn't seem safe face the *edge* of a 4"x4" plate in the lathe. I guess you could embed it in something less wobbly, like between two larger blocks?

Having read the Gingery books and the recent series in one of the machinist magazines, I know some of the procedures of *scraping* (using blue and a reference surface), but that's about it. Are there any guides for filing? Like, what kind of file to use, how to use it to remove material efficiently and how to get opposite sides (more or less) parallel?

None of the milling work for the LMS engine requires precision, but I don't want it to be obviously bumpy and skewed. Maybe just scribe some guidelines and file down to them with an ordinary file? How long is that going to take me?

The material is Al, btw, which I know is kind of gummy and sticks in the teeth.

 

[steamer]

Hey Drysdam,

You can scrape it flat.....but its a lot of work from a rough casting. Certainly it would be better to at least rough machine it flat

And to answer your question, you can most certainly machine it flat on the lathe.

I did some work on a model engine using almost nothing but the lathe in this thread

http://www.homemodelenginemachinist.com/index.php?topic=3951.0

Additionally, I would get yourself a copy of Southbend's "How to run a Lathe"

The age of the copy doesn't really matter as the procedures haven't changed much in the last 100 years.

I believe there is a download on this forum for the Hercus version of this book. Hercus is a "Clone" of the Southbend....or the other way around if your speaking Aussie!....in any case, it's here some where in the download and the price is very reasonable....free.

Some of us have been venturing into scraping. You can find some here

http://www.homemodelenginemachinist.com/index.php?topic=14436.0

You'll need to paw through the thread but it's in there

And ask LOT'S OF QUESTIONS!

I would wait for your lathe if I were you...

Regards,

Dave

 

[drysdam]

I have the Southbend book. I didn't think to consult it for this. Is there something in there about squaring plates on the lathe?

I guess it shouldn't be too hard using an angle plate and a faceplate. Although I'm going to have to consult The Book (or the internet. or my brain.) on how to ensure the edges are square. Then again, I already said that wasn't critical.

 

[arnoldb]

Hi Drysdam

There's a very good tutorial on filing at http://www.homemodelenginemachinist.com/index.php?topic=6781.0

I can highly recommend a bit of practice filing - it might seem difficult at first, but once you get the knack for it, it's one of the most useful skills to have in the shop Thm:

Kind regards, Arnold

 

[tel]

I can highly recommend a bit of practice filing - it might seem difficult at first, but once you get the knack for it, it's one of the most useful skills to have in the shop thumbup

Couldn't agree more - 100 hours on the files should be a mandatory prerequisite for buying a lathe or mill.

 

[Maryak]

Couldn't agree more - 100 hours on the files should be a mandatory prerequisite for buying a lathe or mill.

True,

In our 1st year, apprentices were only permitted to use hand tools, hand hacksaw, files,scrapers and the ubiquitous hammer and chisel. I well remember standing at the first aid station, applying yet another bandaid, (where the hammer had missed the chisel and belted the chisel holder), and gazing wistfully at the machine shop next door. Here, electricity was doing the hard slog and the senior guys were just standing there watching the metal fly.

Best Regards
Bob

 

[drysdam]

That thread is very helpful, but doesn't quite answer all my questions. How do I make sure adjacent sides are square?

For this project it doesn't matter much. I can just scribe a line and file down to it. Or is that more accurate than I'm imagining and you can actually get within .001 that way?

Actually, I bet you just use a reference *square* instead of a reference *flat* just like you do with scraping. You can "bring the flatness around the corner" with the square and then make that whole side flat as usual.

 

[tel]

Actually, I bet you just use a reference *square* instead of a reference *flat* just like you do with scraping. You can "bring the flatness around the corner" with the square and then make that whole side flat as usual.

That pretty much sums it up - just keep working and testing, working and testing and eventually it will all come out right.

 

[Holt]

There is more ways to face the edges on a lathe, depending on the size of the lathe, you can clamp the stock to the crosslide, and mount a mill in the headstock, with a dial indicator you can set it to be square, you could mount it in a 4 jaw independent chuck, and turn the edges. there are more than one way to skin a cat ;D

 

[tel]

I hate skinning cats - smelly damned things they are!

 

[miner49r]

No stationary power equipment? Man has used rocks and sticks before he invented machine tools. Before I had machine tools I used hacksaws, files, chisels, grinders, sand paper, hand drills, etc... Wasn't making models but... Now that gives me an idea.
Alan

 

[steamer]

Oh god...Tel's at it again...what have I done!

;D

 

[bezalel2000]

A

I hate skinning cats - smelly damned things they are!

Yup! A flat cats a good cat

 

[Mosey]

Files. Files are simple. But you can't make anything really difficult or complicated, or precision with them, right?
Back in school, I had the opportunity to visit the Ithaca Gun Company plant. There I saw something extraordinary. There was a room with several old guys working away at solid blocks of steel with files. They were the custom gun department. Their customs cost $20,000.00 and up in the 60's. They were mostly whittled out of blocks of steel with files by these old guys.. They had lots of engraving and gold inlays in them too. Files are good. When they were done, these blocks of steel were very sleek and beautiful. Files can do some very nice things in the right hands.

 

[Tin Falcon]

.

The material is Al, btw, which I know is kind of gummy and sticks in the teeth.

Learning how to run a file is a good thing. when I was in USAF aircraft sheet metal school almost everything was shaped with a file . no mills or power sanders . I have a mill and still find a file is the best tool for certain hings. it is a prefect tool to clean uf the edges of a piece of aluminum .
IMHO recommended reading army TC 5-924 machine tools and ys a section on files if IIRC.
Tin

 

[peatoluser]

you need to rub chalk into the teeth, helps stop it gumming up. I also use a brass bristle brush to clean the teeth as well. I never seem to have enough files. very useful tools.
with buying files, the one thing i've noticed is that the plastic handled multi packs never seem to be of a decent quality so i tend to buy them individualy. at the moment i'm using some made in India and the quality is quite reasonable.
and when you do use a file, remember , just like hacksawing, it's not a race. Go too quick and your putting too much pressure on the backstroke.
Slow and steady gets you there just as quick.
Oh, and always fit a handle. Although I do remember many years ago watching an apprentice going hell-for-leather with a file that on the return stroke he managed to pull the handle off, and because he was going so fast and couldn't stop, the hand with the handle met the hand with the now exposed tang coming in the opposite direction and buried it into his hand. Like I said, slow and steady. Oh and best of luck with your engine build.

That's an interesting comment- "if you don't have a mill, you can just file it" but don't say how
I wonder how old or what schooling swarfrat had? when i went to school metalwork woodwork etc. where part of the curriculum and you left knowing the basics, whereas today they seem to have dissapeared and kids leave school without the basic knowledge to make or fix anything.
mind you, they probably look on me with the same bemusement as I struggle to use a mobile phone!
yours
peter

 

[machinerguy]

Agreed. Files take a learned skill (practice) and the right file. If you're not sure, file down some scrap until your confidence is satisfactory. Don't buy Chineese files!
I used my lathe to make a rectangular 2 cyl. engine block from round bar using facing setups with the 4-jaw. I did the bores similarly. This was a replacement block for the one I had made on the mill-drill and was dissatisfied with.
Providing capacity and tooling, the lathe can do wonders. I've swung some funky time consuming setups on lathes to get a simple surface.
You can do it. Life is learning. If you swing a casting, remember the counterweights!

 

[machinerguy]

Here's an old skill. LAY IT OUT! Lightly the first time, then, after checking, scratch those lines deep enough that you'll be able to see them after lots of handling.
Before you saw out the chunks, tap a series of center punch marks exactly on the lines to which you will file. File half of the center punch divot away, and you're mighty close. Some prefer the automatic ctr punch for consistency of depth, but I can better "feel" the solid punches into the line.
Put up a non-wobbling vise at a height where you have a solid Kung Fu walking stance and your forearms are parallel to the ground while filing. You'll find that all your vise work will be easier. With files you can go from "hogging" to "100 strokes per thou."precision.
A friend recently filed fender and brake mount from a pair of motorcycle fork lowers. He learned, and did well.
I once read, "Show me a self-taught gunsmith without a good library, and I'll show you aman who was taught by a fool."
I'd say you came to the right place.