JSR wants a lathe/mill thread -> JSR buys Sherline

Potatoes last one shot, so build reusable! Discuss ammo designs and ideas. Tough to find cannon part or questions? Ask here!
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jackssmirkingrevenge
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Sun May 22, 2011 8:00 am

Heimo wrote:I have a very old (out of copyright as far as I can tell) book that covers just about all you would ever want to know about every kind of machining operation that existed at the time it was written, I will see if I can scan some key pages to help get you started.... any subjects you are specifically interested in?
Can you tell me the name of the publication, I might be able to download it elsewhere and spare you the hassle :)
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Heimo
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Sun May 22, 2011 8:59 am

jackssmirkingrevenge wrote:
Heimo wrote:I have a very old (out of copyright as far as I can tell) book that covers just about all you would ever want to know about every kind of machining operation that existed at the time it was written, I will see if I can scan some key pages to help get you started.... any subjects you are specifically interested in?
Can you tell me the name of the publication, I might be able to download it elsewhere and spare you the hassle :)
I have been trying to find a digitized version, since I only have this book on loan, but I have not been successful.

I have however found amazon has a couple of used copies for not too much money.

this is the book I am talking about

I will attach a scan of the table of contents to give you an idea to the content of the book.
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here is the table of contents, it should give an idea to content...
here is the table of contents, it should give an idea to content...
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dewey-1
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Sun May 22, 2011 9:05 am

The most popular one I have had experience with since 1973 is the Machinerys' Handbook.

Loaded with information.
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LeMaudit
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Sun May 22, 2011 9:18 am

I suggest this design for a lot of fun ;-)

It is breach loading, so convenient for reloading and maintenance

You can use a cheap taper tap as previously discussed to thread the hole.

You should use a brass plain rod of the proper size and just drill it (keeping enough meat for the thread in the wall thickness). You'll learn how to deep drill and keep a smooth surface. Brass is the easiest material I know to machine. Aluminum is a female doggy in comparison. Also, you don't need fluid cutting with brass, less mess...

There's only simple operations on the lathe, a mill is not needed.


[edit] about books, I have those:

I like this book, specific for miniature machine operations:



This one is nice too, like a huge Sherline catalog with detailed explanations for every attachment available:



And I also have this one, spiral bound, with nice advises for beginners:

http://www.paperbackswap.com/Hobby-Mach ... 968539327/
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Crna Legija
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Sun May 22, 2011 9:56 am

i downloaded this one and its great. i before last year i had never seen a lathe but now at work they let me machine some simple stuff like, key ways and what not. The best part for me was the tool making and sharping.
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LeMaudit
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Sun May 22, 2011 10:15 am

Machinery's Handbook is great, but as a reference when you already know what you want to do and how (or you're told to). And also when you work with various materials, and have access to a lot of tooling like in a machine shop to be able to pick the correct one following the book's advices.

With miniature lathe/mill and limited tooling, what you do is not to pick the correct drill/tap/end mill for the job, but warp the job around the only tap or end mill you have at hand :-D Also you need a lot of creativity to be able to push the limits of your small machines envelope.
If you own a small machine, in my opinion nothing beat a book made for miniature tooling for a beginner, because you find and learn in it only what you can do with your tools, and not all the tricks of the machinist trade.

That's two different paths, either you pick a real size lathe mill combo and then you need to learn by the book, or you pick a "simplified" and smaller tooling, and you need less to learn because either you can't do some operations (and obviously don't need to learn about them), or you need to do them a completely different way than a real size machine.
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Sun May 22, 2011 11:33 am

All listed by others is good as well as www.mini-lathe.com for basic set up and operational fundamentals.
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Sun May 22, 2011 1:34 pm

That's a lot of reading I have to do :D

LeMaudit, much better than my design! I especially like the 2 part cap.

Would it be easy to make a thread to match the schrader? Or am I better off buying an alloy tyre cap and machining it down?
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Sun May 22, 2011 2:00 pm

I believe schraders have 7.7 mm metric threads, and that's not a common tap size. I would go for a machined cap epoxied in place.
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dewey-1
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Sun May 22, 2011 3:04 pm

jackssmirkingrevenge wrote:That's a lot of reading I have to do :D

LeMaudit, much better than my design! I especially like the 2 part cap.

Would it be easy to make a thread to match the schrader? Or am I better off buying an alloy tyre cap and machining it down?
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edit: LeMaudit beat me!
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LeMaudit
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Sun May 22, 2011 3:18 pm

s www.mini-lathe.com for basic set up and operational fundamentals.
Yes this seem to be a pretty good resource to learn.

JSR, we talked about the Sherline line, but those Chinese import mini-lathe are a cheaper alternative, sturdier and bigger.
Most of the time they need some adjustments, the quality is not top-notch, or better said the fitting is not that precise out of the box (that's what I've read on the machinists forum, I don't own one). They are a good and cheaper alternative, but for someone that want to invest time in the tool more than the job, at least in the beginning. I suggest you read this web site, and ask me if I can do, or can't do the same operations on the Sherline. So you'll better know its limitations.

The bigger difference Sherline have with a bigger lathe is the lack of power feed. That mean, you can't go automatically from one point to another at a constant feed rate, and more importantly you can't power thread. The threading attachment on a Sherline is basically a set of gear that you install temporarily outside the lathe, and that link the rotation of the chuck with a precise advance of the tool, giving you a whole range of pitch on any diameter. So it's very precise, but you crank the thread by hand (motor off) ! Slowly, but surely! :D
I believe schraders have 7.7 mm metric threads
Yes, 7.7mm is uncommon, it is in fact SAE 32 NF thread.
I checked with my thread gauge, and it's referenced here:
http://en.wikipedia.org/wiki/Schrader_valve
32 NF is common, but not really in 0.305" 0D.
In this diameter, it would be difficult to make a inside thread, as you would barely have the place to insert a thread cutter. Maybe you could by grinding a miniature one out of a HSS square bar.
The best way yes would be to reuse the thread from an existing brass cap, cut it's top (on the lathe!) and glue it inside a niceeeeeee shiny custom made cap.

[edit] after a quick look on the web it seems this schrader thread is really an oddball. People have difficulties finding taps for them, the best I could find is custom order here : http://www.e-taps.com/products.htm
Definitely a good idea to reuse the thread from a valve cap :-D
Last edited by LeMaudit on Sun May 22, 2011 4:30 pm, edited 1 time in total.
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Sun May 22, 2011 4:24 pm

LeMaudit wrote:
s www.mini-lathe.com for basic set up and operational fundamentals.
Yes this seem to be a pretty good resource to learn.

JSR, we talked about the Sherline line, but those Chinese import mini-lathe are a cheaper alternative, sturdier and bigger.
Most of the time they need some adjustments, the quality is not top-notch, or better said the fitting is not that precise out of the box (that's what I've read on the machinists forum, I don't own one). They are a good and cheaper alternative, but for someone that want to invest time in the tool more than the job, at least in the beginning. I suggest you read this web site, and ask me if I can do, or can't do the same operations on the Sherline. So you'll better know its limitations.
Most of the discussion at mini-lathe is exampling the Sieg lathes. The main problem with the Siergs and Central Machinery lathes is the lash on the dials. Since mine is mechanical I just ignore it. All my work is custom fit and if I need to measure I use a caliper or micrometer.
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Sun May 22, 2011 6:46 pm

JSR,
The problem I see with a mini-lathe is that you'll forever be limited to mini-work, whereas a larger bench lathe can do larger parts (like barrels) AND mini parts too. It might / will be a very short matter of time until you outgrow the capabilities of the mini-lathe and desire a lathe with more capabilities and power. Have you thought of beginning with a lathe slightly larger than a mini?

This 9x20 gear head is small and light weight enough that you could probably wrestle it into the cave with ease yet, it's large enough that you wouldn't outgrow its capabilities for a while. Just one more thing to think about......

http://www.harborfreight.com/9-inch-x-2 ... 45861.html

Cross slide travel: 4-3/8"
Center height: 4-1/2"
Tool slide travel: 2"
Headstock spindle bore: 3/4"
Spindle speed range: 120-2000 RPM
Thread pitches: 8-56 TPI and 0.5-3 mm
Tailstock spindle taper: MT2
Motor: 3/4 HP, 1720 RPM, 60 Hz, single phase
Shipping Weight: 274.00 lbs.

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Sun May 22, 2011 6:54 pm

If you were to recommend a lathe from here or a combo from here is there any one you'd recommend for a beginner?

That store is close to me (120km) and seems fairly cheap.
/sarcasm, /hyperbole
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Sun May 22, 2011 7:08 pm

Hi Zeus

I looked at these machines at the H&F near me; the Sieg (knock-off) in both the mill-lathe and the mill alone. They were frighteningly bad !!
  • Massive backlash on all axis
    Poor finishing on the milling bed
    Hard to reach controls
I got a quote to retrofit the $1500 X3 mill with decent bearings, real ball screws instead of ACME thread, it was another $1900 for parts plus $690 in labour.

I spent almost an hour with the sales guy looking at all the options in the Sieg clones they had; the conclusion was if you wanted to do anything serious and reliable then the Hafco machines at $3500+ was the starting point.
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