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Post by pitobread on Oct 31, 2019 13:35:55 GMT -5
Just cut the stinger short and get john to weld you and ship you a pelton cap to scab on yourself.
You got this.
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Post by 190mech on Oct 31, 2019 19:04:11 GMT -5
Just cut the stinger short and get john to weld you and ship you a pelton cap to scab on yourself. You got this. Good idea!Will need some dimensions for a proper fit,I'm in the game!!  |
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Post by 90GTVert on Nov 1, 2019 0:27:53 GMT -5
Since an ignition will be coming soon, I'll need a way to set the timing. I wanted to try to make my own holder for a dial indicator. I almost ordered an M14x1.25 die, but decided that I've had the lathe way too long to have never tried threading before. I ground a threading tool.  I swapped the gears out for a 1.25 pitch before I did anything else on the lathe. Never changed those before, so I just wanted to see that I could. Kinda clunky with this thing, but it works. I suddenly became really jealous of the guys with big lathes that I've watched just turn dials and move levers to get the pitch that they're after. Set my compound rest to 29.5 degrees and got the tool mounted perpendicular with the fishtail. Zeroed my cross slide with a scratch and then did a quick scratch pass in gear to see if it lined up with a 1.25 pitch gauge, and it did.  I used the never disengage method. Running forward, stopping, backing off the cross slide, running backward, turning in the cross slide, forward again, and repeat. I was afraid I'd forget and disengage the half nut on the lead screw and mess it all up, but I put a piece of masking tape on the lever as a reminder and never touched it till I was done. Looked pretty good to me.   At least until I tried to screw it into a head. I didn't use the TPR head BTW, just in case. Tried 2 heads and it goes 1-2 threads in and I can't turn it anymore. Crap. Looked OK with a thread pitch gauge to my eyes, but that isn't saying a lot. I gave it a quick filing with a thread file. Still a no-go. Tried a wire brush, because it looked like a dirty cut. Thought maybe it would clean it up if it were something small. Nope. I could see that there was a lot of chatter on the threads, so I thought maybe that was the problem. Now that I see pics, I think the major peaks of the thread are too flat, like I didn't cut deep enough. I tried to be careful, so I'm not sure why.   I checked before I started and major diameter was supposed to be able to range from 13.972-13.760mm. My major diameter was 13.92mm. Minor diameter was supposed to be 12.619-12.258mm. I tried to measure that, but I couldn't. I don't have anything thin enough to get in there and check that. I zeroed the cross slide and turned it in 0.030" total. That should take off 0.060". That's 1.52mm. So 13.92 - 1.52 = 12.4mm. Not sure that that is an accurate way to get a minor diameter though. I think I probably should have a wire set and be trying to measure pitch diameter. I dunno. I read the book that John gave me when I got the lathe and watched a lot of videos back then, but I kinda jumped in on what little was left in my memory. Safe to say I underestimated the complexity of properly cutting threads. EDIT : Actually I think I screwed up from the start. The cutter should have had a flat. Without the flat, then I'm messing with the minor diameter and pitch diameter. I'll figure this stuff out one day... maybe. It appears to be really close though. Can't really set it up again to retry to my knowledge. I just ordered a die and I think it will be fine after a quick pass with that. |
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Post by 190mech on Nov 1, 2019 4:25:42 GMT -5
Nice looking work!For a manual lathe its best to use the cut then test fit method,if it doesnt go cut a few more thou and try again.There are thread gauge wires and charts to use them for cut depth measurement for precision work,cut and test is what Ive always used..
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Post by pitobread on Nov 1, 2019 15:33:38 GMT -5
Need to get yourself a machinery Handbook and some thread wires and a 0-1 micrometer.
Looks good, next time test it before you take it off;).
OR this can be great practice to pickup the thread and cut it deeper!
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Post by 90GTVert on Nov 1, 2019 16:13:42 GMT -5
I've got mics. Don't have the handbook or wires. For what little I do, I've just looked specs up online as needed. I'm just gonna stick with running a die over to finish. Don't really want to practice getting it to hit the right spots and then spend more time remaking the part right now. I'm willing to learn, but then sometimes I just want something to work without a whole lot of hassle.
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Post by 90GTVert on Nov 1, 2019 18:37:15 GMT -5
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Post by jackrides on Nov 1, 2019 23:43:36 GMT -5
Beautiful knurling! An artform.
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Post by 90GTVert on Nov 2, 2019 5:06:30 GMT -5
Beautiful knurling! An artform. Thanks, but that part is surprisingly simple on the lathe. |
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Post by 90GTVert on Nov 3, 2019 16:01:32 GMT -5
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Post by pitobread on Nov 3, 2019 16:13:17 GMT -5
If you figure out what the curve is on that thing, post it up.
I've been busy but I want to map those things out because MVT wont tell you what base timing is, says it's a "secret"
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Post by Kenho21 on Nov 3, 2019 18:44:57 GMT -5
Can’t wait to see a video on these things. I’m unfamiliar with them, so excited for you to break it down to two year old level for
people like me haha.
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Post by 90GTVert on Nov 3, 2019 19:56:36 GMT -5
If you figure out what the curve is on that thing, post it up. I've been busy but I want to map those things out because MVT wont tell you what base timing is, says it's a "secret" I should at least be able to tell you base timing when I get there. I'll try to check the curve as well, but no fancy methods here. I'll just rev it up and see what the light shows me. Not sure that's completely accurate, as it seems that lots of things I check have a very gradual retard as RPM gets high... even 4T stuff that seems like it should be flat. |
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Post by ryan_ott on Nov 3, 2019 20:17:54 GMT -5
No tach included with the video but here is a quick check I did awhile back. It’s somewhere around 20-23deg of retard. I know rpm would of been nice to know. youtu.be/YUYFzoCUQ3I |
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Post by pitobread on Nov 3, 2019 23:11:42 GMT -5
I think mapping out the whole curve so you know how much the max is then you can set the base to whatever.
I put the one I had on the RC-One at like 30 degrees base.
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