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Milling machine help for a beginer

cody45
What is the tooing I need to bore a 1" hole in steel plate?
Boring bar??? Im using R8 setup. Do I need an end mill holder or do I use a collet?? thanx for any help.
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Comments

10 comments

Date Votes
  • dcs shooters
    A 1" drill bit with a chuck that fits your machine works good.
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  • shoff14
    Well the main question would be what type of tolerance do you need to achieve?

    There are many options depending on the above answer.

    Option 1

    In many cases a 1" drill will work just fine. You can find a Silver and Deming drill (this is the type) that will have a small enough shank to fit in a 3/4" collet that the R8 allows you to have. You would need a start drill. I would recommend a start drill with the same degrees as your 1" drill. So if you buy a 1" silver and deming drill with a 118 degree tip, by a 3/4" start drill with a 118 degree tip. HSS will do just fine. A good drill and a solid set up, there is no reason not to be able to achieve +/- .003" on a 1" hole.

    Option 2


    Start drill > drill > ream

    For a 1" reamed hole you would drill about .010" - .015" under size. Some people will say 1/32 but I think to much material is removed from a drilled hole. For this setup you would need a 63/64" drill and a 1" reamer. Expected tolerance would be +/- .0004 or so.

    Option 3


    Start drill > drill > bore

    Drilling would be the same as above. Here you would need a boring head for your mill and a boring bar for it. You can purchasing boring head sets and most will come with some type of boring bar. The nicer sets may come with an indexable TPNG or TPG insert. R8 adaptability would be key here. Some heads can be purchased with the R8 taper attached to the boring head. No collet would be necessary.

    Option 4

    Start drill > drill > bore > ream

    Add all the above up, drill size should be about 1/32" under hole size. Bore to remove any drill taper, then ream. Rule of thumb for reaming, half the speed twice the feed.


    Option 5

    1" center cutting endmill. 2 flute endmills will make holes better then 3, 4, 5, 6 flute endmills. Make sure it is center cutting other wise it will not work.


    I think it would be good for you to pick up a Machinery's Handbook and some other machinist teaching guide or books. Enco and MSC are good placings to buy tooling from. They are the same company, however ENCO is a little cheaper and sells more China junk then MSC does.
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  • bambambam
    Shoff has obviously done this before[:D]

    He gave you great advice, you just need to deside your tolerence.
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  • sandwarrior
    I'll go with shoff14 answer # 2. But again, the whole thing depends on your accuracy needs/standards.

    I would start drill the hole a little smaller the 63/64ths. I would go 1/16th under and see what you have.

    At that point I would go one size drill bigger then ream to exactly 1" (2 changes)

    Go slow. If the hole is off center, it'll egg the hole a bit, but you'll know which one to follow when you ream to the final 1".
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  • cody45
    I thank all you guys for your responses. Im really gratefull to have access to your experience. I will get some books but in the meantime Ill follow your advice. thanx again.
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  • bambambam
    I myself prefere boring with a boring bar/head because it makes an almost polished look.

    However, drill and reaming is a great technic for a beginer.

    Just remember to sneak up on the hole size, and don't push real hard on quill because the small bits will end up cutting oversize
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  • cbxjeff
    Check-out McMaster Carr in Chicago. I buy from them weekly, both for work & home shop. As others have said - the proceedure depends on your accuracy requirement.
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  • sandwarrior
    cody45,

    Actually, for the best accuracy if you need a very close tolerance 1", bambambam has it ,in that if you need to true it up, do it with a boring bar.

    Otherwise, center drill, check for accuracy, if good go to the big drill, then ream to final dimension.
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  • cody45
    I have a huge box filled with cutters and tooling that came with the mill. How do I visually tell if a end mill is "center cutting"
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  • Jim Rehm
    A center cutting end mill will have cutting edges that meet in the center of the tool. If the cutting edges do not meet in the center the tool will only cut as deep as the counterbore in the end of the tool. A pilot hole drilled somewhat larger than the central counterbore will allow a multi flute non center cutting end mill to cut a clean hole through a work piece.
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