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Carriage lock mod LMS lathe

Discussion in 'CHARTER OAK AUTOMATION MACHINES' started by Bruce88, Jan 26, 2015.

  1. Bruce88

    Bruce88 United States Active User Active Member

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    Carriage lock mod for (LMS) 8.5 X 16 HiTorque Bench Lathe
    (Similar to Sieg SC4 Lathe)

    This lathe has a carriage lock but taking a picture of it installed is impossible because it is mid-way under the carriage. The best view of it can be found on the exploded parts diagram in the (LMS 8.5x16 Lathe Users Guide.pdf). Ref items #231 (Bridled press plate) and #201(Press plate)

    For those that might want to duplicate this mod, I obtained the material and some parts from McMaster-CARR.
    8910K388 Low-Carbon Steel Bar, 3/8” Thick, ¾” Width, ½’Length
    98867A265 Positioning Stud, M6X1 Thread, 47.5mm Length Overall
    60235K62 Die Cast Zinc Contemporary Style Adjustable Handle, M6X1 Thread

    To lock the original carriage lock required a hex wrench and getting to it was not the easiest and blocked by the Compound Rest sometimes. Putting an adjustable handle in the original lock location would also cause interference problem with the Cross Slide gib screw/nut running into it.

    Also there was a minor problem with the two screws for the Press Plate, if the screws where tightened it would cause the carriage to be locked/hard to move. There is no information concerning the screws in the user guide, my guess is the Press Plate will wear itself in like the gib slides do and the screws will need to be checked on occasion to make sure their lightly snug until they wear in. Note there are two Press Plates on the carriage one on the left side area of the carriage and one on the right side area of the carriage I’m only making a new Press Plate for the right side area.

    Two problems with doing this mod. Getting the Press Plate and Bridled Press Plate out & into the slotted area of the carriage without dropping them into the carriage box. I used a pensile magnet to prevent this from happening and I also made the new Press Plate with the step and inboard M5 screw location drilled/tapped with the raw stock 2 – ½ inch long to back mark the second hole, after drilling/tapping the M4 second hole the new press plate was cut to length. Also when I drilled the right hand M4 fastener hole in the carriage casting to accommodate the M6 stud, I didn’t want to disassemble the carriage and to prevent drilling grit from getting into the carriage box I used a vacuum and rag in the slot area to prevent the grit from going in there.

    The original Bridled Press Plate was relocated to the right hand out board hole location and the M5 tapped hole in it was enlarged to M6 tapped hole. Also on final installation I found I need to shorten the M6 stud by approximately .15 inches to clear the carriage box.

    carriage lock 1.jpg

    Carriage Lock 2.jpg
    Carriage Lock 3.gif
    Carriage Lock 4.jpg
    Carriage Lock 5.jpg
    Carriage Lock 6.jpg

    carriage lock 1.jpg Carriage Lock 2.jpg Carriage Lock 3.gif Carriage Lock 4.jpg Carriage Lock 5.jpg Carriage Lock 6.jpg
  2. Bill C.

    Bill C. United States Active User Active Member

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    Nice job and great pictures.
  3. TIGL

    TIGL United States Active User Active Member

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    Sorry to necrobump this old thread but I'm trying to figure out whats wrong with my carriage lock. If I turn the M6 screw into the Bridled press plate it gets tight without actually locking the carriage. I thought it was in this thread but somewhere I saw that if thats the case, the press plate is turned 90 degrees. what parts would I need to remove to access and fix that? It's not clear from the exploded parts diagram in the manual.

  4. higgite

    higgite General Manger - Proofreading Dept. Active Member

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    Hi TIGL,

    The way I got to the press plates on mine to fix that problem was to trim a strip of heavy paper long enough and narrow enough to slide under the plates from the right side of the apron. Then I unscrewed the set screws all the way out to let the plates rest on the paper and pulled them out of the apron on the paper “sled”. Just reverse the procedure to reinstall the plates.

    To fill the gap between the bridled press plate (231) and plain ol’ press plate (201), so the 231 plate can’t spin when you try to tighten it, I JB Welded a piece of M5 key stock to the side of one of the plates (I forget which one). The 231 plate now has no room to spin and the carriage lock now works in less than 1/2 turn of the set screw. Hope this helps.

    Last edited: Feb 23, 2017

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