Chevy V8 Scale Engine Plane

Discussion in 'Plans' started by TrashCo, Jan 23, 2014.

Help Support HMEM by donating:

  1. Oct 28, 2019 #141

    Cogsy

    Cogsy

    Cogsy

    Well-Known Member Staff Member Global Moderator

    Joined:
    Jul 30, 2012
    Messages:
    2,706
    Likes Received:
    774
    Gender:
    Male
    Location:
    Perth, Western Australia
    Lower than center on a parting tool is not the recommended way to set it up. If your parting tool isn't sticking out much then bang on center is best but if you've got a bit sticking out then slightly (very slightly) high will account for some flex in the blade and get you back to center. If you're a bit too low you run the risk of the part riding up over the blade as you get to the center and potentially wrecking the part and the blade/insert.
     
    justintime likes this.
  2. Oct 28, 2019 #142

    davidyat

    davidyat

    davidyat

    Well-Known Member HMEM Lifetime Supporter

    Joined:
    Dec 29, 2012
    Messages:
    213
    Likes Received:
    45
    Gender:
    Male
    Occupation:
    Retired/Self Taught Machinist
    Location:
    Indianapolis, Indiana
    Thanks for the advice. Most of my parting is on soft metal, brass, aluminum, etc. Yes there is a slight nub after parting, but I'm cutting the part a little bigger than I need it and mill it down to what I want with a fly cutter on both sides. If I'm doing multiple pieces, I face off the round I'm working on for the next piece, zero out the parting tool and take it to the dimension I want. Most of the time, by the time the parting tool gets close to center, the nub is so small that the weight of the part causes it to just fall off. But, again, thanks for all the advice. I never want to stop learning.
    Grasshopper
     
  3. Jan 25, 2020 #143

    SailplaneDriver

    SailplaneDriver

    SailplaneDriver

    Well-Known Member

    Joined:
    Nov 27, 2017
    Messages:
    92
    Likes Received:
    19
    Gender:
    Male
    Occupation:
    Retired Electrical Engineer
    Location:
    Woodinville, WA
    After a long break, I finally got all the rocker arms and rollers done but the roller pins are my new issue. My ER32 metric collets won't grip the 1/16" stock and I don't have a 5C 1/16" collet. Will order one and go that route.

    I'm looking at making the valves next so I can finish up the heads. I need advice on how to turn the stems. I've found recommendations for step cutting, using a follow rest, a center, a female center, and Joe Pie's single cut to diameter. I think these are in the order of complexity high to low for cutting. What do you guys do? These valves have .094 diameter .866 long stems and I anticipate using .25 drill rod for stock. I could go to larger stock to improve stickout for Joe Pie's method.
     
  4. Jan 25, 2020 #144

    johnl

    johnl

    johnl

    Member

    Joined:
    Jan 31, 2013
    Messages:
    15
    Likes Received:
    0
    I used a center. I left the stem 1" long and used a #1 center drill. Trimmed to length.
    I tried the step method but didn't have much luck.
     
  5. Jan 25, 2020 #145

    John Antliff

    John Antliff

    John Antliff

    Well-Known Member

    Joined:
    Aug 7, 2018
    Messages:
    55
    Likes Received:
    33
    Gender:
    Male
    Location:
    New Zealand
    Jo Pie's method is certainly quick once you have the right setting however you don't have any control of the surface finish although you can cut slightly oversize and reduce using a file and emery paper. Slowly slowly catchee monkey for me! I've used the step method but once again you have to reduce the length tothe required size with abrasive to remove the inevitable steps. A centre is the time served method which works!
     
  6. Jan 26, 2020 #146

    Cogsy

    Cogsy

    Cogsy

    Well-Known Member Staff Member Global Moderator

    Joined:
    Jul 30, 2012
    Messages:
    2,706
    Likes Received:
    774
    Gender:
    Male
    Location:
    Perth, Western Australia
    I only ever make them using the step method but generally my stems are a bit bigger at 1/8". I aim to hit +0.01mm oversize to allow me to blend the steps with wet and dry and have them polish up for a nice fit in the guide. Generally the very first step of the very first valve is the tough/slow one as I use a finished guide as a stop/go gauge to get my number to aim for. From there it's not too difficult a task and it's fairly rare to mess one up. I do try to make them all in one session once I get into the rhythm. 1/4" stock sounds about the right starting size to me.
     
  7. Jan 26, 2020 #147

    deverett

    deverett

    deverett

    deverett HMEM Supporter

    Joined:
    Sep 6, 2007
    Messages:
    1,124
    Likes Received:
    220
    Occupation:
    Retired
    Location:
    Skibbereen, West Cork
    Or consider two piece construction.
    Use the correct size rod for the stem, put in the groove/cross drill for the retainer, cut off a bit longer than required. The extra length is reduced so the head won't slip up the shaft then silver solder a piece of stock to that. Hold the stem in the collet and finish machining the head. You can use the extra length and put a screwdriver slot in it for lapping valve and seat. Finally cut off the extra.

    Dave
    The Emerald Isle
     
  8. Jan 27, 2020 #148

    justintime

    justintime

    justintime

    Member

    Joined:
    Jul 14, 2010
    Messages:
    14
    Likes Received:
    4
    Gender:
    Male
    Occupation:
    retired Mould Maker / Machinist
    Location:
    South Jersey , USA
    Never use the cut-off tool below center. Dead on or a few thousandths high is preferred. Scale method is really only applicable when doing full cut off operation, to get " close enough " to what your machine can handle without " fighting " the tool. Good Luck.
    .
     
    Cogsy likes this.
  9. Feb 16, 2020 at 11:47 PM #149

    SailplaneDriver

    SailplaneDriver

    SailplaneDriver

    Well-Known Member

    Joined:
    Nov 27, 2017
    Messages:
    92
    Likes Received:
    19
    Gender:
    Male
    Occupation:
    Retired Electrical Engineer
    Location:
    Woodinville, WA
    Got all the rocker arms done a bit ago. Holding these tiny parts was a real challenge. I accidently juggled the container I had the rollers in and tossed them all over the shop. I found three of the 12 I had in the container. The rest are keeping the dust bunnies company.

    P1260972.JPG

    After numerous attempts I finally succeeded in making one valve. I settled on a step method with a single cut to depth with roughly .25 steps. Only 15 more to go. I still have to put the seat on the valve but I'll do the valve seats the same time as I do the valve cages to make sure I get them at the same angle. These miniscule parts are a pain - very easy to shear off if you aren't very careful. And don't drop them otherwise you'll never see them again.

    P2160974.jpg
     
    awake and mayhugh1 like this.
  10. Feb 17, 2020 at 5:00 PM #150

    stevehuckss396

    stevehuckss396

    stevehuckss396

    Model Engineer Project of the Month Winner HMEM Supporter

    Joined:
    Nov 19, 2008
    Messages:
    4,151
    Likes Received:
    1,028
    Gender:
    Male
    Occupation:
    Construction
    Location:
    Sterling Heights, MI
    Did you deviate from the drawing? It looks like there is a radius cut into the under side of the rocker by the roller.
     
  11. Feb 17, 2020 at 5:59 PM #151

    SailplaneDriver

    SailplaneDriver

    SailplaneDriver

    Well-Known Member

    Joined:
    Nov 27, 2017
    Messages:
    92
    Likes Received:
    19
    Gender:
    Male
    Occupation:
    Retired Electrical Engineer
    Location:
    Woodinville, WA
    Steve, you have a good eye! The one on the left does have a radius where I overturned the rotating table. I used it for a test fit. The image below is a bit closer and should show in better detail the spring relief. I don't believe I deviated from the plans. All of the other rockers match this one - well at least half since the other half reverse offset.

    P2170975.jpg
     
  12. Feb 18, 2020 at 2:38 PM #152

    stevehuckss396

    stevehuckss396

    stevehuckss396

    Model Engineer Project of the Month Winner HMEM Supporter

    Joined:
    Nov 19, 2008
    Messages:
    4,151
    Likes Received:
    1,028
    Gender:
    Male
    Occupation:
    Construction
    Location:
    Sterling Heights, MI
    Good deal. That material needs to be there.
     

Draft saved Draft deleted

Share This Page

Group Builder