TB2 - Elmer's Coomber #46
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Powder keg
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I think the oillite would be a good idea.
Wes
Wes
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Standard SAE841 oil impregnated bronze bearings are only about $0.60 each in that size range. No machining necessary. A flange would not be necessary as they are made to press fit into a hole. Flanged ones are available, but are only necessary if you have a high axial load. You might want to press in a bearing that is slightly longer than the material is thick so it could act as a spacer to keep the flywheel hub from rubbing the bearing mount.
Gail in NM,USA
Gail in NM,USA
BobWarfield
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Brass_Machine said:
Well darn. That means the fixture I'm building only works for 4 parts and I have to figure out a new fixture for the other 4. No worries, we'll git 'er done.
BW
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I'm going to try some 6061 tool plate for the bearings I'm making. The print calls for hard aluminum or brass. I will be sure to get a good finish so that a polish can be easily achieved. Might even drag the camera out to the shop to document some part of it. I know now how much you all like pictures ;D
Dick
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Looking at the pics in Divided He Ad's engine build thread, I see he made an arbor for turning his flywheel. I am wondering if this is necessary for our flywheels. Areas in which I am ignorant are:
1) Once the flywheel is cut off from the bar, how difficult is it to mount a 3/8" disc in a chuck and get the face square?
2) If the outer perimeter is polished before being parted off, will the chuck jaws mar the finish when machining the reverse face?
1) Once the flywheel is cut off from the bar, how difficult is it to mount a 3/8" disc in a chuck and get the face square?
2) If the outer perimeter is polished before being parted off, will the chuck jaws mar the finish when machining the reverse face?
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I think it really depends what you have on hand for tooling. If you have soft top jaws you can approach it totally different . This flywheel doesn't have a full radius rim so it can be done with just the chuck but will take some fudging to get it true. If your chuck isn't dialable you might need to make a stub arbor to hold by the bore for the final OD truing. Faces shouldn't present to much trouble to get parallel. You could leave a slight shoulder on the OD to register the jaws against.Then slip it on a stub arbor and take a final cut to true the OD up.I would save the final polishing for the last step. I'm sure there are others who have crossed this bridge many times and can offer suggestions with yet another and possibly much simpler approach.
Dick
Dick
B
Bogstandard
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Kvom,
Speaking thru experience, you do all your flywheel truing up first, then do the polishing at the end.
If you look at these two previous posts, they should give you some ideas how to do it.
http://www.homemodelenginemachinist.com/index.php?topic=1809.0
http://www.homemodelenginemachinist.com/index.php?topic=844.0
Hope this helps on your journey
John
Speaking thru experience, you do all your flywheel truing up first, then do the polishing at the end.
If you look at these two previous posts, they should give you some ideas how to do it.
http://www.homemodelenginemachinist.com/index.php?topic=1809.0
http://www.homemodelenginemachinist.com/index.php?topic=844.0
Hope this helps on your journey
John
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Great idea John, I've never used that tape method but I'm sure it will work very well! I'm learning something new already! ;D Kirk my only suggestion to this would be to face one side of each one to get better adhesion with the tape and surface contact against the jaw faces because the stock I sent is sawcut both sides. Straight but sawcut none the less.
Dick
Dick
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John,
I had read those posts before but ithe idea didn't stick. I think that's the way to do it. In any case I was plannimng to turn one face before parting off.
On another topic. I was wondering what the mathematical description of the cam would be, so performed the following "analysis" this morning.
Define L as half the length of the piston rod + fork/wheel, S as the stroke the piston makes from either side of the center, and D as the distance of the cam from the center of rotation. Using standard notation, where 0 degrees is the positive X axis and angle increases counter-clockwise, we see that at 0 and 180 degrees D=L from the center of rotation. At 90 D=L+S, and at 270 degrees D=L-S. So the arc formula should be D=L+S*sin(angle).
Looking at the drawings we see that L=1+1/16" and S=1/4".
Given this it would seem possible to draw the cam using a good protractor and rule (i.e., plot points and join with a french curve).
I had read those posts before but ithe idea didn't stick. I think that's the way to do it. In any case I was plannimng to turn one face before parting off.
On another topic. I was wondering what the mathematical description of the cam would be, so performed the following "analysis" this morning.
Define L as half the length of the piston rod + fork/wheel, S as the stroke the piston makes from either side of the center, and D as the distance of the cam from the center of rotation. Using standard notation, where 0 degrees is the positive X axis and angle increases counter-clockwise, we see that at 0 and 180 degrees D=L from the center of rotation. At 90 D=L+S, and at 270 degrees D=L-S. So the arc formula should be D=L+S*sin(angle).
Looking at the drawings we see that L=1+1/16" and S=1/4".
Given this it would seem possible to draw the cam using a good protractor and rule (i.e., plot points and join with a french curve).
OK, folks. I have 16 blocks cut and drilled ready for profiling. As best I recall that covers the number of folks participating. Can someone confirm please? Also there was some discussion early on about putting a tag on the bottom, that would require a recess to be machined in. I don't recall the consensus but speak now or never. I haven't seen much chatter on this lately, either everyone is done or procrastinating even worse then I.
Brian
Brian
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Brian,
It does not look like anyone really cares about any form of name plates. I was waiting for some response, but we did not get any response the last time you and I asked about it. I guess just leave them off.
The cam rings have been finish machined for a while, but I still have to polish them and then fill the logo in the billboard on top. Only an evenings work to do that. I will wait until there is a movie I want to watch on TV and do it then. That is when I do most of my mindless type hand work. I turn off the TV when I turn on any power tool.
Gail in NM,USA
It does not look like anyone really cares about any form of name plates. I was waiting for some response, but we did not get any response the last time you and I asked about it. I guess just leave them off.
The cam rings have been finish machined for a while, but I still have to polish them and then fill the logo in the billboard on top. Only an evenings work to do that. I will wait until there is a movie I want to watch on TV and do it then. That is when I do most of my mindless type hand work. I turn off the TV when I turn on any power tool.
Gail in NM,USA
Brass_Machine
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I wouldn't mind name plates... but for some reason I thought Powderkeg was doing them ???
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Brass-Machine,
It could be that Powder Keg was going to do some. I don't remember it, but some days I don't remember my name until after the first pot of coffee.
Brian and I had gotten off topic discussing them in the cam ring thread starting about post #9.
http://www.homemodelenginemachinist.com/index.php?topic=2714.0
Wrong place for the discussion to be, but it happened.
In any event, I am game for anything that anyone wants to do that way if it is helpful. I suspect that Powder Keg still has his hands full on the domestic front.
Gail in NM,USA
It could be that Powder Keg was going to do some. I don't remember it, but some days I don't remember my name until after the first pot of coffee.
Brian and I had gotten off topic discussing them in the cam ring thread starting about post #9.
http://www.homemodelenginemachinist.com/index.php?topic=2714.0
Wrong place for the discussion to be, but it happened.
In any event, I am game for anything that anyone wants to do that way if it is helpful. I suspect that Powder Keg still has his hands full on the domestic front.
Gail in NM,USA
Has this thread been moved or has the project been halted. Just curious. That #46 looks cool.
