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Thread: Lathe milling attachment

  1. #1
    Join Date
    Sep 2008
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    Default Lathe milling attachment

    I have set out to build a milling attachment for my 14x40 lathe and although I have a couple of ideas I would rather not reinvent the wheel as the old saying goes. Any advice on doing this or any pitfalls to look out for would be much appreciated!

  2. #2
    Join Date
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    This has been discussed before. Check out:

    http://bbs.homeshopmachinist.net/sho...=milling+lathe

    http://bbs.homeshopmachinist.net/sho...=milling+lathe

    http://bbs.homeshopmachinist.net/sho...=milling+lathe

    I also have a small X-Y slide that I am setting up with an angle plate and the table you can see in two of the above posts. This will be more like the commercial milling attachments. But I believe it will be a lot stronger and more versatile. It will have a lot more mass for dampening vibrations when the angle plate and my table is included in the mount. Sorry, no pictures yet.

    You ask about pitfalls. The most obvious is that lathe ways are not designed for milling. Even with the carriage locked down, vibrations can be a problem and cuts will need to be light, slow, and carefully planned. You will not be able to use the full HP of the lathe for milling cuts. Another, less obvious problem, is that if you use the cross slide movement of the lathe, you may have problems with it's squareness or lack of it. The cross slide on a lathe is not necessairly square to the long axis. Given that some error will exist in this spec, many manufacturers (probably all) choose to error in the direction that would make a facing cut on the lathe CONCAVE. That is, the center wil be slightly hollow. This will produce a cylinder that will sit flat on a flat surface without rocking. If the cross slide angle were off the other way, then the face of a turned cylinder would be convex and it would rock on the center point when seated on a flat. This would be instantly objectionable in most parts so it is rejected.

    When I have tried to mill a flat surface with a fly cutter style tool in the lathe, this can be a real problem. Instead of a flat, you can get a concave or convex surface or if the part is too large to completely pass the fly cutter, a combination of both. That is, concave on one end and convex on the other. This definitely limits the size of the work you can do and there is no simple solution.

    Also, the surface of the cross slide of a lathe has no real need to be completely level to the ways. That is, a lathe tool will cut equaly well even if this surface is at a slight angle. When you mount a table or vise on this surface, in place of the compound rest, this angle can be transfered to the work piece and the overall angle of the tool to the work is not the expected 90 degrees. This can also be a problem. I have used the table shown in the above posts and some shims under the work mounted on it to make up for this.

    Even worse, on old lathes like mine, the cross slide top surface may not even be flat. My SB is perhaps 70 - 80 years old and this surface was about +/- 0.003". I had to do a lot of work on it to get it flat but it is still slightly tilted.
    Last edited by Paul Alciatore; 01-24-2009 at 04:11 PM.
    Paul A.

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  3. #3
    Join Date
    Mar 2004
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    Denmark
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    Hi Radkins

    If you as I will be able (lucky) to obtain a large cross slide from an industrial lathe, you can have a milling attachment that is nicely heavy.


  4. #4
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    Apr 2001
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    Clinton, WA
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    I might have one for that size lathe for sale. If your interested PM me or call the number on my web site.
    Mark Hockett

  5. #5
    Join Date
    Feb 2007
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    379

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    Most lathes are set to face slightly concave, this may impact some operations, especially fly cutting.

    This kind of thing is a much more elegant (but expensive) way to do the job

    http://cgi.ebay.co.uk/Myford--Lathe-...102114001r6281

    I used a cheap little version of this type of attachment for a while before I put together a nice benchtop mill. Using your carriage for X and cross slide for Y works nicely & you can use the lathe's feeds too,
    Regards,
    Nick

  6. #6
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    SF bay area, California, USA
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    M Kilde: Are you the person who made the Side LEver engin in the magazine? What lathe is that? It looks like mine.

  7. #7
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    Mar 2004
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    Denmark
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    Hi Teenage_Machinist

    Yes I'm the person who made the Side Lever.

    My lathe is a chinese build, I believe the brand is "Eagle" - the model is named HD210x320 as you can see in the photo, this refers to the work diameter and the maximum lenght between centers.
    I chose this engine because it has manuel gear shift via V-belt (6 speeds), most small lathe today is with variabel electronic speed control, but I do not trust the quality of these (especially chinese) systems.

  8. #8
    Join Date
    Dec 2007
    Location
    Mercer Island WA USA
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    I have one for my 1938 Atlas.
    I am going to use it with a metal saw for making M70 cuts on an M98 safety shroud.

    The Atlas can go really low r.p.m.s that the saw likes.
    If corporal punishment for women and children is domestic violence, then gun control is domestic spying.

  9. #9
    Join Date
    Nov 1999
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    SE OZ
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    Default Small lathe milling.

    Quote Originally Posted by radkins
    I have set out to build a milling attachment for my 14x40 lathe and although I have a couple of ideas I would rather not reinvent the wheel as the old saying goes. Any advice on doing this or any pitfalls to look out for would be much appreciated!
    Thanks radkins.

    These might be of some help:

    My lathe (10 x 30) with my ER-32 collets and adaptor (uses a 4-3MT sleeve as well as a draw-bar - just like the mill):
    http://i200.photobucket.com/albums/a...rSmith01-1.jpg

    http://i200.photobucket.com/albums/a...AirSmith03.jpg

    Some of the stuff that can bolt/clamp to my cross-slide:
    http://i200.photobucket.com/albums/a...AirSmith04.jpg

    http://i200.photobucket.com/albums/a...AirSmith06.jpg

    http://i200.photobucket.com/albums/a...AirSmith09.jpg

    These vises will bolt on too and are very accurate all over and pull down tight with no "lifting moving jaw" problems:
    http://i200.photobucket.com/albums/a...Vise/Vise2.jpg

    Here is their specs (I have checked some of them and they agree with the spec sheet):
    http://i200.photobucket.com/albums/a...Vise/Vise1.jpg

    You can fix a swivel-based vice to your lathe as well. This one may be a big big, but I am sure you will get the idea. I have also shown a small vice that I have that came with my micro-lathe (6 x 10):
    http://i200.photobucket.com/albums/a...Vise/Vise1.jpg

    I have other micro-lathe stuff that might help. If you like, let me know (this thread) and I will snap them and post the pics.

    Despite what some may say (not in this thread), there is no good reason why light milling cannot be done in a lathe - large or small - either in a good 3 or 4-jawed chuck or in collets.

    You are only limited by your imagination, confidence and the capabilities and size constraints on your lathe.

    VP's publications are full of projects done on a lathe.

    Evan's portfolio is an excellent example of what can be done on a lathe - perhaps he will post a link to it for you as it really is an "eye-opener" of what is possible.

    Paul Alciatore's post (this thread) is an object lesson in clarity and focus as regards this subject - a re-read of it is well worth the time.

  10. #10
    Join Date
    Sep 2008
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    Wow, you guys have given me something to think about and the info from this thread has made me completely change my ideas about how I was going to do this, no point in describing what I had in mind you all have given me some better ideas. I need to scrounge up a few parts and I plan to start on this thing right away, I already have started actually.

    Thanks to everyone and I genuinely appreciate your taking the time to share, The pics and other info is going to be a real help!

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