Very glad that I see you continuing with the build.---This build isn't for sissies. You will learn to figure out a few things before you are done here.---Brian
That is a problem with files for example, if you press evenly then move it back and forth, the middle of the pin is in contact with the file more than the edges and you get a low spot in the middle.
Bob---Sorry you hurt yourself. I've had a few whacks from the chuck, but nothing hospital worthy. I'm not exactly afraid of my machines, but I treat them with a great deal of respect.
Bob, Sorry to hear about your injury. It happens, just be glad it wasnt more serious then it was.
Thanks for posting your CNC adventures. I love seeing the fixtures and how the machining is done. I'm self taught also and use these post for learning. I'm also applying my new CNC skills to model building.
Jerry
Brian says he uses the same cam on all his engines, here's the cutter path for the T-head engine using a 1/4" endmill, with the XY0 at Y-.04 so you can cut it from a piece of 3/4 stock. It's for a Yasnac control with a tool changer and was originally for a 1/2" mill going full depth so feeds and speeds aren't correct and it uses adaptive cutter paths so you'll probably need/want to do some editing, at least the finish pass should be good. Hope it works for you.Thanks, Jerry.
Re: the CNC adventures, I've been working on the G-code for the CAM, which combines arcs from three different circles. I did a similar approach on the Webster's cam, but the Webster's cam was a simpler design that had a couple of straight lines in it while Brian's cam has no straight lines.
The simple way to do that is to dump the cam into my CAM program. The drawback is the motion is done as straight line segments, so the curves are approximated as stair steps. First off, it's ugly, but more importantly is that I'm not sure it doesn't harm the function.
Brian says he uses the same cam on all his engines, here's the cutter path for the T-head engine using a 1/4" endmill, with the XY0 at Y-.04 so you can cut it from a piece of 3/4 stock. It's for a Yasnac control with a tool changer and was originally for a 1/2" mill going full depth so feeds and speeds aren't correct and it uses adaptive cutter paths so you'll probably need/want to do some editing, at least the finish pass should be good. Hope it works for you.
%
O100 (BRIANS CAM.TXT)
N01 G17 G20 G40 G49 G80 G90
N02 G00
N03 G91 G28 Z0
N04 G91 G28 X0 Y0
N05 T6 M06 (1/4 FLAT ENDMILL - ROUGH)
N06 G90 G54 X-.5786 Y-.0622 T16 S2450 M03
N07 G43 H6 Z.1
N08 Z-.7
N09 G01 Z-.8 F31.
N10 X-.5419 Y-.0665
N11 G17 G03 X-.5002 Y-.0413 I.0046 J.0395
N12 X-.4911 Y-.0116 I-.1569 J.0643
N13 X-.4871 Y.008 I-1.095 J.2373
N14 G02 X-.4754 Y.0668 I2.5641 J-.4773
N15 X-.4498 Y.1556 I.6334 J-.1349
N16 X-.3925 Y.2664 I.4821 J-.179
N17 X-.2359 Y.411 I.3959 J-.2717
N18 X-.0641 Y.4695 I.2363 J-.4127
N19 X.033 Y.475 I.0642 J-.2695
N20 X.1689 Y.4432 I-.0477 J-.5092
N21 X.3779 Y.2858 I-.1723 J-.4462
N22 X.2041 Y-.4276 I-.3779 J-.2858
N23 X.1777 Y-.4393 I-.2938 J.6294
N24 X-.1548 Y-.4487 I-.1777 J.3993
N25 X-.3557 Y-.3131 I.1601 J.454
N26 X-.4519 Y-.1423 I.3559 J.313
N27 X-.462 Y-.0883 I.2601 J.0765
N28 X-.4626 Y-.0234 I.4331 J.0364
N29 X-.4314 Y.133 I.5806 J-.0344
N30 X-.3673 Y.257 I.4667 J-.1627
N31 X-.1864 Y.4066 I.3709 J-.2643
N32 G03 X-.1802 Y.4106 I-.0145 J.0293
N33 G02 X-.147 Y.4348 I.2068 J-.2489
N34 X-.0628 Y.4698 I.147 J-.2349
N35 X.033 Y.475 I.0628 J-.2698
N36 X.1356 Y.4415 I-.0331 J-.2751
N37 X.1842 Y.4157 I-1.4699 J-2.8215
N38 X.2558 Y.3701 I-.3092 J-.565
N39 X.3523 Y.2763 I-.2901 J-.3948
N40 X.4449 Y.0449 I-.3567 J-.2769
N41 X.4271 Y-.1323 I-.4466 J-.0447
N42 X.1778 Y-.4392 I-.4272 J.0923
N43 G03 X.1828 Y-.5135 I.0164 J-.0362
N44 G01 X.1941 Y-.5169
N45 G03 X.2451 Y-.4752 I.0114 J.0381
N46 G01 Z-.7
N47 G00 Z.1
N48 X.1577 Y.5006
N49 Z-.7
N50 G01 Z-.8 F31.
N51 G03 X.0986 Y.4625 I-.0396 J-.0035
N52 G01 X.1356 Y.4415
N53 G02 X.1759 Y.4141 I-.1393 J-.2473
N54 X.2148 Y.381 I-.5345 J-.6685
N55 X.258 Y.343 I-1.216 J-1.4259
N56 X.315 Y.2835 I-.4076 J-.4477
N57 X.3825 Y.1757 I-.3583 J-.2994
N58 X.3913 Y.1546 I-.4603 J-.2035
N59 X.4269 Y-.1334 I-.3913 J-.1946
N60 G03 X.5094 Y-.1263 I.0423 J-.0092
N61 G01 X.2841 Y.4293
N62 G03 X.2148 Y.381 I-.0401 J-.0163
N63 G02 X.3826 Y.1712 I-.5602 J-.62
N64 X.3915 Y.1542 I-.4923 J-.2685
N65 G03 X.4142 Y.1344 I.0355 J.0178
N66 G02 X.425 Y.1281 I-.0145 J-.0369
N67 G01 X.4468 Y.11
N68 X.4853 Y.0781 Z-.785
N69 X.5142 Y.0541 F394.7
N70 G02 X.5283 Y.0203 I-.0252 J-.0303
N71 G01 X.5266 Y.0013
N72 X.5249 Y-.0176
N73 G02 X.5172 Y-.0723 I-.6939 J.0698
N74 G01 X.5088 Y-.1186
N75 G02 X.4835 Y-.2146 I-.6372 J.1159
N76 X.4472 Y-.2942 I-.4504 J.1577
N77 G01 X.4419 Y-.3034
N78 X.4366 Y-.3126
N79 G02 X.3627 Y-.4047 I-.3591 J.2125
N80 G01 X.3548 Y-.4121
N81 X.347 Y-.4194
N82 G02 X.2768 Y-.4712 I-.2863 J.3145
N83 X.1934 Y-.5131 I-.3535 J.5997
N84 X.1056 Y-.5451 I-.371 J.8823
N85 G01 X-.0188 Y-.5836
N86 G02 X-.0624 Y-.5688 I-.0116 J.0376
N87 G01 X-.0891 Y-.5315
N88 X-.1182 Y-.4908 Z-.8 F31.
N89 X-.1298 Y-.4745
N90 G02 X-.1329 Y-.4694 I.0334 J.0237
N91 G03 X-.1548 Y-.4487 I-.0362 J-.0162
N92 G02 X-.4265 Y.055 I.1548 J.4087
N93 X-.3789 Y.1888 I.4816 J-.0963
N94 X-.2839 Y.3107 I.3924 J-.2077
N95 X-.1807 Y.4102 I.6304 J-.5507
N96 G03 X-.2433 Y.4542 I-.0251 J.0308
N97 G01 X-.2491 Y.4379
N98 G02 X-.252 Y.4316 I-.0388 J.0138
N99 G01 Z-.7
N100 G00 Z.1
N101 X-.4982 Y-.0041
N102 Z-.7
N103 G01 Z-.8 F31.
N104 G02 X-.5085 Y.0469 I-.0346 J.0196
N105 G01 X-.4897 Y.0324
N106 G03 X-.4265 Y.055 I.0243 J.0315
N107 G02 X-.3727 Y.1884 I.4322 J-.0971
N108 X-.283 Y.3118 I.7195 J-.4287
N109 G03 X-.281 Y.3616 I-.03 J.0261
N110 G01 X-.2993 Y.3862
N111 Z-.7
N112 G00 Z.1
N113 G91 G28 Z0
N114 T6 M06 (1/4 FLAT ENDMILL - FINISHING)
N115 G90 G54 X-.0313 Y.5644 T16 S2500 M03
N116 G43 H6 Z.1
N117 G01 Z-.8 F20.
N118 G41 D46 X.1652 Y.4098 F15.
N119 G17 G02 X.3698 Y.1735 I-.5116 J-.6498
N120 X-.3698 Y.1735 I-.3698 J-.2135
N121 X-.1652 Y.4098 I.7162 J-.4135
N122 X.1652 Y.4098 I.1652 J-.2098
N123 G03 X.5162 Y.4516 I.1546 J.1964
N124 G40 G01 X.3198 Y.6062
N125 G00 Z.1
N126 G91 G28 Z0
I edited my post and added some comments for the codes you may be unfamiliar with.Thanks! I'll have to look at that in my G-code simulator and see what it looks like. There are codes in there I've never seen before.
Meanwhile, I've been rounding up the metal stock I need but didn't pick up when I was starting because it seemed like the sizes I could buy were absurd compared to what I need. Like I need about 1" length of a O-1 tool steel to make the cam, and the smallest bars I could find were 36" (that 1" I quote is over twice the finished length of the cam).
Bob,
One thing you might want to research is case hardening. This is where you use a low carbon mild steel and only hardend the surfaces that need it. I have not made my camshaft yet and I am going to try this. I will be using this: BROWNELLS SURFACE HARDENING COMPOUND | Brownells
I have not case hardended mild steel before, but I am going to give it a try.
The cost of the hardening compound may be more than the 01 tool steel. Also I have read posts here where the camshaft gets distorted during case hardening. So take all of this with a grain of salt.
Greg
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