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HF 7 x 10 Bed Upgrade to 7 x 16 with extension

Discussion in 'HARBOR FREIGHT, CENTRAL MACHINERY & BUSY BEE' started by TomVil, Feb 3, 2017.

  1. TomVil

    TomVil United States Iron Registered Member

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    City:
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    State:
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    I finally sprung for the LMS 7x16 bed extension upgrade. But I took it one step further- I added the old 7x10 bed to the 7 x 16 that provides a total of about 26 inches between centers!
    To provide a continuous bed, I cut down the 7x10 removing the left side motor and gear box mounting surface and milled open the gap between the ways to match the new bed.
    I'll post pix as soon as I get them this weekend.
     
  2. tweinke

    tweinke United States Active User H-M Supporter-Premium

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    Very interesting! How do you align everything? how about the leadscrew?
     
  3. TomVil

    TomVil United States Iron Registered Member

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    Well, I bolted the two beds together by drilling and tapping the two ends and the entire lathe is bolted down to the bench using the ordinary mounting holes. The bench has a base made with a 3/4" MDF and two 1.5" 80-20 aluminum extrusions running the entire length to hold the alignment. The 80-20 extrusions have 'Tee slots' , to bolt down the lathe, much like a milling machine table. I also bolted the extrusions down to the bench top MDF board.
    I extended the rack to drive the carriage but not the leadscrew. The only unsolved issue is the end bearing for the leadscrew. I need to remove the end bearing in order to pass over the end of the leadscrew with the saddle, to make use of the far right extension.
     
  4. TomVil

    TomVil United States Iron Registered Member

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    Here are some Pix of the Bed Extension IMG_2646.JPG IMG_2647.JPG IMG_2648.JPG IMG_2649.JPG IMG_2650.JPG
     
    rdean likes this.
  5. Billh50

    Billh50 Active User H-M Supporter-Premium

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    Tom,
    How did you make sure both beds are the same height and straight with each other? Or didn't you bother since you aren't machining at the far end ?
     
  6. Bill W.

    Bill W. United States H-M Supporter - Premium Content H-M Supporter-Premium

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    Good question, Bill... Looks to me like the way it's set up, that the extension only allows you to get the full use of the original bed. Maybe he shimmed the extension to compensate for the thickness of the chip pan. Hard to tell from the photos. You would still need to make sure the extension was accurately aligned so the tail stock is where it should be to line up with the chuck. Hmmmmmm.... Bill W.
     
  7. Billh50

    Billh50 Active User H-M Supporter-Premium

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    I had planned to extend mine but health got in the way. I was planning on milling and scraping the end of mine square with the bed. Then doing the same to the donor bed. That way I could bolt them together and get a good alignment. I had already checked the height of both on a surface plate and I can scrape the donor into the same height as my original. So when I bolt them together everything would slide nice. I checked every dimension I could on both beds for a perfect fit. As far as the lead screw I was going to turn the end of 1 to fit in a bored hole of the other. Then align the threads using a close fitting nut with a pilot hole for drilling to instal a small pin. After pinning I was planning on a couple drilled dimples I could spot weld for extra strength. And hand file the weld for a smooth transition.
     
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  8. tweinke

    tweinke United States Active User H-M Supporter-Premium

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    Looking past accuracy issues and the logistics of getting a good setup I would think this was a pretty good way to get more length. If the leadscrew was the full length it would be even more awesome. Sometimes working with what you have got and thinking outside the box is very rewarding. :encourage:
     
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