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Thread: Horizontal Milling - Where to start ?

  1. #1

    Default Horizontal Milling - Where to start ?

    A couple of weeks ago I posted that a Bridgeport with a Malnar horizontal milling attachment had followed me home. Once it got off the truck, it was up to me, my back, and a pry bar to move it 25 feet across the shop floor to it's new location. That took me 2 days, 1/8'th inch at a time. Being retired I have the time to do such projects. Being retired my back was not thrilled with the project.

    The Bridgeport is a thing of beauty and a joy to use. YAY. Tonight I have tried the Malnar attachment for the first time. I don't have an arbor yet, but the machine came with several B&S #10 tool holders so I used a 1.5" dia side cutting end mill and took a few passes. I learned something - namely, I don't know what I'm doing.

    I think I should make an arbor and an arbor support. What sort of steel should I use for the arbor? I don't plan on taking huge depths of cut or using 8" wide cutters, but if I need to use 4140 or O1 or something I'll do it.

    Secondly, I think I should get a good horizontal milling cutter. That way, if the finish isn't good then it isn't the cutter's fault - it means I'm still climbing the learning curve. There are a number of new or NOS horizontal cutters on our favorite auction site, but I don't know if I should get a 2.5 diameter or 4" diameter. Is there any disadvantage to buying a 2" wide cutter? I don't have any plans to mill 2" wide material at this time, but is it better to have too wide or narrower and use multiple passes? (1 HP motor).

    Pointers to videos or sites about horizontal milling would be appreciated too. I've got a long journey on this one, and a few maps would be good.

    Photos and maybe even a video coming soon...

    Thanks
    Dan

  2. #2
    Join Date
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    OK.

    Yes you will need an arbor and overarm with arbor support. And eventually an overarm support to really make it rigid.

    First up, assess your milling attachment.

    Are whatever it has for bearings good and not sloppy?

    Do the toolholders fit tight and without slop?

    What is the SLOWEST rpm you can get with the attachment? I think I remember it being all belts for the drive, which is not as nice as some gears, but will work. (I have 5:1 back gears and belt reduction before that).

    OK To work regular cold rolled mild steel/machine steel/boiler plate/1018/etc, you want the cutter to be at about 100 SFM. That's about 100 RPM with a 4" dia cutter. For tool steels, and some others, you want more like 40-50 SFM, so 40-50 rpm with 4" cutter. For aluminum multiply by 3, so you may want to have 300 rpm with 4" cutters for aluminum.

    4" cutters are a good plan, because they give you good clearance under the arbor. You need to have room for the arbor and spacers to go over the work, over the hold-downs, studs and nuts, etc. 4" cutters are by no means perfect for that, but better than smaller ones.

    Arbors are not too hard to make. The taper is the only troublesome part.

    You will have an arbor the diameter of the cutter bore. That will be 7/8" for many gear cutters, 1" for some cutters, and 1 1/4" for other cutters. The arbor will also require spacers, to go between the cutter and the ends of the arbor, to hold it steady. The nut on the outer end of the arbor clamps them against the cutter

    The arbor will need at least one keyway (refer to machinerey's handbook to find sizes for the arbor diameters) on each arbor. Some sizes may need two to cover all possiblities, in which case put them opposite each other.

    For an end bearing, you can use either a rediuced size journal (I did that), OR bearing sleeves that go over the arbor in place of some of the spacers. Sleeves are handy, but they take up room on the arbor. Make the arbor longer if you use them. I;d advise against the plan of running the arbor against a center cone on the end. I just don't like that plan.

    Arbors are rarely straight, so as you cut you will hear a pulsating "rrrrrrrrrrRRRRRRRRRrrrrrrrrrrrrrRRRRRRRRRrrrr rr" as the areas where the cutter duts deeper and shallower go thru the work. If you hear that everything is happy and working.

    There will usually be some banging as the cutter gets into the work, Once you have a couple teeth in the work at all times, it should settle down to a happy cutting noise as above. If NOT, you have something wrong. Check it out before it messes up your part.

    DO NOT TRY "CLIMB MILLING" IT WILL NOT WORK AND YOUR PART WILL BE MESSED UP. You will not be able to control climb milling, it WILL take off on you with any serious depth of cut. Feed the work into the cutter as it rotates against the feed (conventional milling)

    Always clamp down twice as much as you think you need to. Horizontal mills will push the part off the table if it is pushable. Almost as bad as a shaper, but not quite.

    Arbors I made

    7/8" made of CRS years ago, still fine.


    1 1/4", made of 4140, no better than the CRS for the 7/8", really.


    Chomping through steel with a 2" high helix cutter on a 1" arbor. Note the bolt-down vise and extra support from overarm to knee . Backgear is "in", note the lever is UP on the backgear bracket at right.


    Cutting a gear. Looks like I just finished the last pass. Note that the dog driver actually clamps the dog to avoid any movement during a cut.
    Last edited by J Tiers; 04-21-2017 at 12:53 AM.
    1601

    Keep eye on ball.
    Hashim Khan

  3. #3
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    Great topic, the horizontals don't get much attention these days. Jerry, did you get your shop-made spacers ground on the ends? Adam Booth has a video showing the arbor bending due to a tiny bit of error/damage to one of the spacers. He had to put them on the surface plate to work out which one was causing it because there was no obvious problem.

  4. #4
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    where to start with a horizontal mill? Get a tool and cutter grinder. Seriously. The cutters are very expensive to buy, and you definitely sharpen those big expensive cutters vs binning them. There are piles of used ones lurking that otherwise weill get scraped. Those piles were probably more plentiful a few years ago, but they are still out there for you to find
    Last edited by Mcgyver; 04-21-2017 at 11:15 AM.
    .

  5. #5
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    I think J Tiers covered it fairly well, however don't be afraid to run HSS cutters at 50 fpm rather than 100 fpm depending on the coolant system or lack thereof.

    Surface finish with HSS tools doesn't suffer from low fpm as can happen when using carbide cutters.

    Dave

  6. #6
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    I just bought a universal horizontal milling machine (Hardinge) older machine.Everything seems to be in very good condition except the y axis which has considerable backlash.A new nut and lead screw will be in the making soon.The mill was connected to a vfd when I bought it, but the fellow wouldn't sell the vfd. I have a new Leeson, US made, vfd which I will hook up shortly.

  7. #7
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    YES to the T&C grinder. You will want it. Any cutters you get used will likely need sharpened, and you will need to sharpen them from time to time. If you sharpen as soon as they start to cut less well, you will end up taking off less overall than it you wait until you HAVE TO sharpen them.

    Do not even think about trying to hand sharpen any. Maybe for just stoning burrs off an edge, that's OK.

    Used cutters are the way to go. I managed to luck into about 200lb of assorted cutters for $50 from a shop that was closing. There was not a one in there that would cost as little as $50 if bought new. Some that I could not use, I sold and got my $50 back, they were huge roller chain sprocket cutters (1" rollers), and the like.

    Quote Originally Posted by pinstripe View Post
    Great topic, the horizontals don't get much attention these days. Jerry, did you get your shop-made spacers ground on the ends? Adam Booth has a video showing the arbor bending due to a tiny bit of error/damage to one of the spacers. He had to put them on the surface plate to work out which one was causing it because there was no obvious problem.
    I cheated and bought them through Victor Machinery in NYC. If I had a good SG I'd probably make them.
    1601

    Keep eye on ball.
    Hashim Khan

  8. #8
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    I have a few horizontal milling cutters I could be persuaded to part with. PM me if interested.

    metalmagpie

  9. #9

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    Quote Originally Posted by Mcgyver View Post
    where to start with a horizontal mill? Get a tool and cutter grinder. Seriously.
    Is there one specifically for horizontal milling cutters?

    Thanks
    Dan

  10. #10
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    Probably not, but the good news, you can get by without an airspindle..

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