# Beginner



## Deck Dog (May 21, 2010)

I have had a Unimat 3 for over 30 years in that time I only ever used it to make model ship fittings. I have decided to try my hand at a simple steam engine and some members here gave me some good ideas. I recently purchased a larger lathe (7 x 12 Metal Worker Lathe ...same as the Micromart 7 x 14 lathe) and a Micromart mini milling machine. As I have used mostly "soft " metals before I need some advice about the harder metals like CRS. Also how deep should I make the milling cuts for any metal? Also on the mini lathe (an MT 3 ) I find that the drill chuck that came with the lathe tends to fall off when doing milling. I have put in the collet with a bolt as a draw bar and it appears to wobble a bit. What am I doing wrong?


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## Blogwitch (May 21, 2010)

DD,

A tapered fitting chuck shouldn't really be used for milling at all. 

The main reason is that almost all milling is done using interrupted cuts (the timing between each cutting face or edge) which sets up a continuous vibration that will soon loosen off any tapered fitting. The other reason is that you are mounting a very hard cutting tool into hardened jaws of a chuck, so the cutter is liable to creep out of the chuck jaws when cutting. 

You will notice that twist drills have soft shanks and should not be intermittent cutting, so the taper isn't shaken apart, and the jaws can grip onto something soft.

The usual solution for milling using a lathe is to buy yourself a collet chuck that will fit into your lathe spindle.

I am sure lots of people will come to your aid with where to get the cheapest type from, once we find out what part of the world you come from. It is no use me giving you web addresses in the UK, if you live in Outer Mongolia.

Hope this helps

Bogs


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## Troutsqueezer (May 21, 2010)

Be sure to post some pics of your first build as you go along. And your shop too. Welcome. 

-T


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## Tin Falcon (May 21, 2010)

> I find that the drill chuck that came with the lathe tends to fall off when doing milling.


Do dot use a drill chuck for milling.
use a collet or end mill holder.
As I have used mostly "soft " metals before I need some advice about the harder metals like CRS.

aluminum and brass are often used in this hobby. 12L14 steel is a favorite it is easy to machine. 



> Also how deep should I make the milling cuts for any metal?


depth of cut is a function or your machine and in the case of a mill the diameter of your tool. find the correct feed and speed for what you are doing then experiment some with doc. 
look here this should get you started. 
http://www.homemodelenginemachinist.com/index.php?topic=9413.0
and on the x2 mill use a dial indicator o get your downfeed otherwise it is a WAG. Just loosteing and tightening your z lock may feed .002 to .005 very unpredictable. 
Tin


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