Horizontal Milling

[Martin CargillParticipant @martincargill50290]

I purchased a Victoria U1 horizontal mill a few months ago. After fettling most of its problems, converting it to single phase and then getting all 1.25 tons of it into my workshop I'm now at the stage where I can start playing with the beast! Then it suddenly struck me that apart from the time I spent in the training school at the start of my apprenticeship some 40 years ago I haven't ever used a horizontal mill.

I have a large selection of cutters but I don't know what speeds, feeds or depth of cut etc. that I can run them at. Can anyone provide any general guidance or point me towards any suitable literature.

Martin

[Martin CargillParticipant @martincargill50290]

[IanTParticipant @iant]

Hallo Martin,

I have a Victoria HO and an Atlas MF – both horizontals..

As a suggestion, have a look at the Yahoo 'Atlas Shaper and Mill' Group and in their 'files' section you will find (in amongst all the Atlas specific stuff) some PDF files from Practical Mechanics (circa 1950's) and elsewhere that detail using a horizontal (including feeds/speeds etc). These articles were 'sponsored' by Atlas, so unsurprisingly feature an Atlas mill but give quite a good laymans (e.g. hobbyist) guide to using any horizontal mill. They will not help you with using the 'universal' features of your mill (or its maintenance) but should help to get you going – they did for me…

Regards,

IanT

[BazyleParticipant @bazyle]

It is the same as other cutting operations – you require the effective cutting speed through the metal to be about right, then maybe tweak it if it sounds strained. So use the diameter of cutter and rotational speed to calculate the speed of the cutting edge. Or rather move the equation around to get the rotational speed from the required cutting speed.

Then with the rotational speed and number of teeth known you can work out the number of cuts taken per second and adjust the feed rate to make each cut take a sensible bite.

[Anonymous]

Posted by Martin Cargill on 19/10/2017 20:47:50:

I have a large selection of cutters but I don't know what speeds, feeds or depth of cut etc. that I can run them at. Can anyone provide any general guidance or point me towards any suitable literature.

Cutting speeds are the same as for any other machine tool. So, for HSS cutters, say 100fpm in low carbon steel, less for cast iron, more for brass. I always use flood coolant, where appropriate; there's a lot of heat being generated if you're running the cutter hard.

Depth of cut and feed can be much bigger than you think. It's taken me a while to learn that. I rarely use less than 4 thou per tooth and often quite a bit more. It all depends on how well the work is clamped!

The universal bit is straightforward, but you do need a universal dividing head to make best use of it.

A few pictures might help. Milling hot rolled steel, width of cut 1", depth of cut 3/8" and 6 thou per tooth:

Cutting a 5DP gear in cast iron in one pass:

Hobbing a worm wheel:

Cutting a 6DP helical gear in one pass:

To summarise, it's a big, heavy mill, don't pussy foot about but give it some welly!

Andrew

[sean logieParticipant @seanlogie69385]

Even on my toy centec2 compared to Andrews, the depth of cut you can take is surprising. I’ve been taking .250 thou cuts in mild steel with a 1/4″ wide cutter and I’ll be trying the same in cast iron this weekend . As Andrew states, its all down to the clamping down of the workpiece. .

Sean

[Simon Williams 3Participant @simonwilliams3]

Echo Andrew's comments about clamping – don't let the work get away from you! Certainly to begin with be overcautious, not only does it wreck the work if it slips, if it gets sucked into the mangle you WILL damage something. You will be lucky only to bend the arbor. All of my problems with a horizontal mill have been because I was over-optimistic in how I clamped things. Clamping in this context means solidly bolted against a positive stop to resist the reaction from the cutting action.

Which brings me to rule 2 – DON'T CLIMB MILL! If things slip while climb milling you've got breakages on your hands in a fraction of a second. Yes., I know climb milling has its uses, but not on a horizontal (of this vintage) until you've got some gut feel for how the clamping forces on the work piece, also the inevitable backlash on the machine work.

Good luck with your new toy (I'm jealous!)

Best rgds Simon

P.S. As a rough guide, a 4 inch diameter HSS cutter will be happy at about 100 rpm, a bit less if your mill has lower gears.  If it rattles and bangs a bit, play with the feed rate.  You may find it's happier with a good size tooth load rather than letting the cutter rub.

Edited By Simon Williams 3 on 27/10/2017 12:06:49

[vintagengineerParticipant @vintagengineer]

The other advantage of a horizontal mill is you can gang mill specific profiles by arranging different cutters on the arbour.

[Ian S CParticipant @iansc]

When I bought my Rexon mill about 32 years ago, I bought a 3 cutter 50 mm face mill, and never having used a mill before, I asked the sales man (machinist, or so he said), how fast, what depth of cut, what feed. Reply, give it about 1 mm depth of cut, about 900 rpm, and crank like hell, well it worked, even though they gave me the wrong cutters for it as I found when I went to buy some new ones.

Ian S C

[not done it yetParticipant @notdoneityet]

I've been taking .250 thou cuts in mild steel

Somehonw I think sean means 250, not one quarter of one thou! (chuckle)

[David Standing 1Participant @davidstanding1]

Posted by not done it yet on 27/10/2017 13:43:41:

I've been taking .250 thou cuts in mild steel

Somehonw I think sean means 250, not one quarter of one thou! (chuckle)

Beat me to it

[sean logieParticipant @seanlogie69385]

I see not done now is still being a PITA with the kindergarden antics …. chuckle chuckle

Sean

[Anonymous]

Posted by Simon Williams 3 on 27/10/2017 12:00:58:

Clamping in this context means solidly bolted against a positive stop to resist the reaction from the cutting action.

Which brings me to rule 2 – DON'T CLIMB MILL! If things slip while climb milling you've got breakages on your hands in a fraction of a second.

It is interesting to note that in the first picture in my post above the work is not bolted down in the conventional sense. Between the clamps and the work is a piece of ¼" plate with a machined edge, which the work butts up against so it can't move axially. At the other end are three hexagonal nuts on eccentric screws in T-nuts which push the work against the ¼" plate. But there is nothing holding it down as such, it relies on the cutting forces being down and along.

My mill has a backlash adjuster for climbing milling. It works via a worm and worm wheel to turn a second nut on the table leadscrew. However, the knob moves from end to end very easily. I would have expected there to be some resistance part way through as the second nut took up the backlash. So I don't think the system is adjusted properly. It's a right faff to take the table off to fiddle with it, so for the moment I don't climb mill on the horizontal. It's on the round tuit list.

Andrew

[Simon Williams 3Participant @simonwilliams3]

Andrew – Thanks for the explanation of how that aluminium plate is clamped onto the mill table – I'd wondered how you'd done it, very ingenious. You've elegantly made my point for me – the cutting forces are reacted by positive location – i.e. against a positive shoulder and against the bed of the mill, not by friction. Yes the positive shoulder relies on friction against the bed of the machine, so it's only part true, but it's always easier to get something tight and solid against the tee slots, that's what they do.

I've been trying to find the reference I remember which examined the difference in security of a work piece where the cutter forces were reacted by positive location (eg cutting at right angle to the vice jaws) as against cutting along the line of the jaws, where it's only the friction between the jaws (clamping force) and the work to react against the cutting forces. Using toe clamps to hold something down as you would with a vertical mill onto the table, then approaching it with a nice big side and face cutter is going to end in tears.

Anyway, if the OP is just starting to familiarise himself with the way a horizontal mill can bite a work piece it's positive location location location.

Your backlash adjustment sounds fascinating, and I'd like to know some more. I haven't got anything that fancy. When you do get roundtuit can we see some piccies?

Best rgds Simon

[Anonymous]

The "aluminium" plate is actually hot rolled steel. The hexagonal nuts and eccentric screws were commercial items, but I made my own T-nuts.

Early on I had a wobbly on the horizontal mill wherein it threw a lump of steel onto the floor because I'd clamped it to an angle plate only with G-clamps. Lesson learnt. For the reasons stated I rarely use the machine vice, preferring to clamp to the table or angle plates/box cubes. Many of the parts I machine on the horizontal are castings, so holding them in the vice is difficult anyway.

Here is a picture of the backlash control, it's the round knob bottom right:

The knob turns freely, but smoothly, over ¾ of a turn. I'm wondering if it should turn more than that? It certainly never feels tight. I should have played with it more when I had access.

Andrew

[Martin CargillParticipant @martincargill50290]

Many thanks to all who replied. I now have a grasp on what the cutters I have are capable of. I now need to get the engine crane out and remove the vertical head, so that I can try some horizontal milling

Martin

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