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Thread: BSF 70 Breech bolt

  1. #1
    Join Date
    Feb 2004
    Location
    salisbury
    Posts
    481

    BSF 70 Breech bolt

    The breech bolt on my BSF 70 is stuck. The previous owner has tried to undo it which has chewed up the head and I have made it worse! The original part is no longer available but I wondered if the bolt from an Original 35 or 27 might fit? Has anyone replaced the breech bolt with a non standard part who can help? Thx
    when there's lead in the air there's hope!

  2. #2
    Join Date
    Jun 2013
    Location
    Sheffield
    Posts
    1,960
    Try & look at a HW 50 or similar.

  3. #3
    Join Date
    May 2005
    Location
    malta
    Posts
    646
    If the bolt's head is useless and can't get a grip on it, you can find the exact centre of the exposed threaded end, centre pinch and drill through the bolt after applying penetrating oil to the threads. Probably the bolt will undo itself leaving the female thread intact. Alternatively drill through the damaged head end using a left hand twist drill with your power tool in reverse rotation.

  4. #4
    Join Date
    Feb 2009
    Location
    bideford
    Posts
    2,902
    I've used an impact driver before to free seized breech bolts. One smart tap usually does it.
    Choose the biggest bit that fits well.
    If you can get it out, there may be a chance of dressing it up to reuse it.
    B.A.S.C. member

  5. #5
    Join Date
    Feb 2004
    Location
    salisbury
    Posts
    481
    Thanks All,

    I have tried several days of W D 40 and tried tapping hard and using an impact driver to no avail, including heating it up. I am going to have to drill it out but will need to replace. Until I get it out I wont know the exact spec of the thread etc, but it has three scallps in the head to allow for a smaller locking screw. The Diana screws have a similar arrangement although only two scallops for the locking screw and I wondered if one might fit. I guess otherwise I will have to get one made up...
    when there's lead in the air there's hope!

  6. #6
    Join Date
    Jun 2013
    Location
    Sheffield
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    WD40 not that good for this , penetrating oil is better & would need to be left submerged in it .

    If all the normal methods have failed you can drill from the threaded side . Use a drill press with a 2mm drill bit & go down about 4mm or so. Keep trying to unscrew as normal as you go.
    Did you get the lock screw out ok ?

  7. #7
    Join Date
    Feb 2004
    Location
    salisbury
    Posts
    481
    Thanks for the info. I can report that I have had a bit of help today and got the screw out and the head re shaped/blued and as good as new! V Happy!
    when there's lead in the air there's hope!

  8. #8
    Join Date
    Jun 2013
    Location
    Sheffield
    Posts
    1,960
    Good result .

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