Free 186 More Best Homemade Tools eBook:  
Get tool plans

User Tag List

Results 1 to 3 of 3

Thread: Rock Maple Soft Fixture for Boring Thin Parts

  1. #1
    Supporting Member Paul Jones's Avatar
    Join Date
    May 2014
    Location
    Del Mar, California
    Posts
    1,231
    Thanks
    5,810
    Thanked 1,459 Times in 657 Posts

    Paul Jones's Tools

    Rock Maple Soft Fixture for Boring Thin Parts

    The cylinder head for a small compound steam engine required thin cylinder liners made from silicon bronze. This operation required machining the low and high pressure cylinder liners to 1.250" and 1.500” OD respectively and then boring the liners to final ID. The low pressure and high press cylinder liners will be press fit into the compound steam engine cylinder block with an interference fit just under 0.0005” requiring close tolerances.

    Using rock maple, I created a faceplate fixture for holding the cylinder liners for boring. The fixture requires the bronze cylinder OD and ID to be concentric and to grip the part uniformly without distortion. I first cut the rock maple fixture on my table saw and also cut a centered slot for part clamping. Boring the fixture to 1.501” using a face plate with clamping straps (1/8" thick x1/2" wide and held with M6X1 machine screws) ensures the concentric OD alignment of the bronze parts when boring the ID. I also bored a 0.25” deep by 0.1 wide bottom step in the rock maple fixture for holding the bronze part a safe distance away from the faceplate (and also bored additional bottom-hole clearance at the center of the fixture for boring tool bottom relief). Note, a temporary thin piece of wood added to the center slot allowed rough boring of the fixture and then removed, and the fixture final bored to size for clamping the bronze cylinder. The 1/4-20 machine screw is for clamping the part and easier removal.

    In case you are wondering, I made another slotted “cylindrical liner” from aluminum for holding the smaller diameter high pressure cylinder liner in the larger diameter rock maple fixture. I plan to reuse the fixture for building more of these engines but could have machined the smaller liner first and then re-bored the fixture for the larger liner for a one-time operation.

    186 More Best Homemade Tools eBook

  2. The Following 4 Users Say Thank You to Paul Jones For This Useful Post:

    Christophe Mineau (Jan 1, 2015), JTC (Jul 13, 2019), kbalch (Jan 2, 2015), PJs (Oct 23, 2015)

  3. #2
    kbalch's Avatar
    Join Date
    Jun 2012
    Location
    Clermont, FL
    Posts
    5,034
    Thanks
    2,275
    Thanked 532 Times in 384 Posts
    Thanks Paul! I've added your Boring Fixture to our Lathes category, as well as to your builder page: Paul Jones' Homemade Tools. Your receipt:


    2,000+ Tool Plans

  4. #3
    Supporting Member Catfish's Avatar
    Join Date
    Oct 2013
    Location
    Mariposa, California
    Posts
    272
    Thanks
    57
    Thanked 420 Times in 158 Posts

    Catfish's Tools
    Nice fixture. Even very large steam pumps have Si bronze liners. Thanks for sharing, Randy



    2,000+ Tool Plans

  5. The Following User Says Thank You to Catfish For This Useful Post:

    Paul Jones (Jan 5, 2015)

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •