Size

The Shed - - Milling -

In a typ­i­cal home-engi­neer­ing work­shop pro­gres­sion, you buy a bench vice, some hand tools, and pos­si­bly a bench grinder. Af­ter you buy a small pil­lar drill then comes a big leap — buy­ing a cen­tre lathe.

Along the way you ac­quire more small tool­ing, drills, turn­ing tools, etc. You make many use­ful items and pro­duce a fair bit of scrap.

But then you find that the lovely pieces you are turn­ing out on your lathe re­quire other fea­tures, es­pe­cially holes more ac­cu­rately po­si­tioned than you can mark out and drill on your pil­lar drill. As good as you have be­come with a file, that flat sec­tion needed on the shaft re­ally needs to be ma­chined. And how are you go­ing to make a slot for that key­way?

Milling ma­chine

An­other even big­ger leap is now re­quired — a milling ma­chine. With this, you will be able to ac­cu­rately pitch out holes, ma­chine flat, ma­chine slots, ma­chine an­gles, square-up edges, and maybe start that model steam loco you promised your­self.

This leap of­ten seems to be very daunt­ing and it ac­tu­ally may be, in part due to the dif­fer­ent milling-ma­chine types — all cen­tre lathes are ba­si­cally the same lay­out and just vary in size.

There are two main, ba­sic milling­ma­chine con­fig­u­ra­tions, hor­i­zon­tal and ver­ti­cal (re­fer­ring to how the spin­dle of the ma­chine is mounted), with a few that are both.

In this first ar­ti­cle of our in­tro­duc­tion to milling, we will look at the most use­ful type for the home work­shop: the ver­ti­cal milling ma­chine. So, once you have made the case for buy­ing a ver­ti­cal milling ma­chine, new or sec­ond hand, what you should be look­ing for?

What­ever you plan to make, don’t for­get that when friends find out about your pur­chase, they will al­ways have car and boat parts for re­pair or mod­i­fi­ca­tion. So, un­less you are go­ing to be a clock­maker, you may want a ma­chine big enough to cope with some of the typ­i­cal sizes of car or boat parts. How­ever, no mat­ter what size ma­chine you buy, you can be sure that the first jobs you are asked to do will be too big for your new pur­chase.

Un­less you have lots of space and money, though, don’t get car­ried away with size. When you have a typ­i­cally small job to do, a very large ma­chine can be very un­gainly to use. The work­ing foot­print of a milling ma­chine is also gen­er­ally larger than its base size, so don’t for­get that when you plan the ma­chine spot in the work­shop, you need to al­low space for ta­ble move­ments and the pos­si­bil­ity of a work­piece over­hang­ing the ta­ble.

Power

Do you have sin­gle- or three-phase power avail­able? Sin­gle phase makes things eas­ier as you can plug in and go. But check the cur­rent re­quired, as a 10A sup­ply may not be suit­able and you may need to up­grade the wiring. If you have three phase, this will open up your op­tions with the pos­si­bil­ity of us­ing ex-in­dus­trial equip­ment.

You get better start­ing torque from three phase than from sin­gle phase and three phase is much eas­ier to run in re­verse. This is very use­ful in some pro­cesses, for ex­am­ple, re­vers­ing the spin­dle to wind out a tap if you have been tap­ping un­der power.

Con­vert­ing ex-in­dus­trial equip­ment to sin­gle-phase mo­tors is not al­ways an op­tion due to space lim­i­ta­tions, as sin­gle­phase mo­tors are usu­ally larger than their three-phase equiv­a­lents. But the use of a sin­gle-to-three-phase con­verter may be an op­tion, as most smaller ma­chines tend to be sin­gle phase. If you buy new, you may be able to choose sin­gle or three phase.

New or sec­ond hand?

Is the well-used Bridge­port mill at that price as good as a new, im­ported ma­chine with a war­ranty?

There are some very good sec­ond-hand ma­chines out there, but worn out is worn out, no mat­ter what the name on the side. The lat­est ma­chines com­ing out of Asia are now well worth con­sid­er­ing. You may also be able also to do a deal on a start­ing tool­ing pack­age with your new ma­chine.

When look­ing at a ma­chine, be it new or sec­ond hand, find your­self a friendly tool­maker, miller, or model en­gi­neer to help you as­sess the suit­abil­ity of your prospec­tive pur­chase. 

When you have a typ­i­cally small job to do, a very large ma­chine can be very un­gainly to use

Pete Wood­ford shows the quill lever low­er­ing the spin­dle to­wards the ta­ble

The all-im­por­tant axes of move­ment in a milling ma­chine

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