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Post by Deleted on Nov 11, 2018 18:47:25 GMT
D[/quote] David You're not the first to make that mistake. Ipswich, Penrith, Newcastle, Sandringham, Woolwich, just to name a few English towns, are all named after their Australian counterparts, just ask any Aussie.  Jim
[/quote] yes...it's the same for all those towns named after their US namesakes...  |
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Midland
Elder Statesman
Posts: 1,875
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Post by Midland on Nov 11, 2018 19:46:11 GMT
Keep going D[/quote] David You're not the first to make that mistake. Ipswich, Penrith, Newcastle, Sandringham, Woolwich, just to name a few English towns, are all named after their Australian counterparts, just ask any Aussie. Jim
[/quote] Yes Jim, fancy those people up North dropping the New from York. Now here is one for you (& Lisa) do you know where the "Goyder Line" is? Cross it and you answer to me!!! Just because you love Midland locos will not let you off, Lisa maybe!!!! David |
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Post by Jim on Nov 11, 2018 21:28:43 GMT
It's still there David in South Oz and it still works too as the farmers will tell you. I'd never cross it for fear of what could happen to me despite hiding behind a nice Midland Clayton coach. Jim.
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Midland
Elder Statesman
Posts: 1,875
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Post by Midland on Nov 11, 2018 21:57:27 GMT
It's still there David in South Oz and it still works too as the farmers will tell you. I'd never cross it for fear of what could happen to me despite hiding behind a nice Midland Clayton coach. Jim.
BRAVO!!. My great Uncle a few times removed!!! D |
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Lisa
Statesman
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Post by Lisa on Nov 13, 2018 22:16:47 GMT
I made a start on the pistons this morning, faced one side then drilled and tapped for the piston rods. I'll finish these to length and diameter once they're mounted on the piston rods, to ensure concentricity. Out of interest, I put one of the piston rods in the 3-jaw chuck just to see how out-of-true it is; surprisingly it's out by less than a thou, so I'm tempted to think that's just fine and go with it. Ideally I'd have a collet chuck to mount them in, but I don't, and I'm not sure I could get it much closer in the cheap 4-jaw I bought which is being problematic again.  |
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Lisa
Statesman
Posts: 806
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Post by Lisa on Nov 15, 2018 17:13:36 GMT
Can anyone think of a reason why this setup is a bad idea?  Piston rod in the mill collet chuck, as both the lathe and mill have a 3mt spindle. It'll need a custom (longer) draw bar, as the one on the mill is too short, and it's not actually that much more true than the 3-jaw chuck; but I think I prefer the setup. Thoughts? |
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Post by simplyloco on Nov 15, 2018 17:20:27 GMT
Lisa Nothing wrong with that at all. As a bonus you'll find that the lathe stops a lot quicker! John |
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Lisa
Statesman
Posts: 806
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Post by Lisa on Nov 15, 2018 17:25:26 GMT
Lisa Nothing wrong with that at all. As a bonus you'll find that the lathe stops a lot quicker! John Reminds me of when dad first bought the Taig lathe, which requires you to supply a motor. Dad used a sewing machine motor, which had a brake built-in so that it stopped immediately when power was cut, so the motor stopped but the chuck didn't; being a screw-on chuck it promptly unscrewed itself, rolled across the bench, and landed in his lap. He removed the brake to stop that happening, and later switched to a different motor. |
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Post by Roger on Nov 15, 2018 23:07:27 GMT
Can anyone think of a reason why this setup is a bad idea? Piston rod in the mill collet chuck, as both the lathe and mill have a 3mt spindle. It'll need a custom (longer) draw bar, as the one on the mill is too short, and it's not actually that much more true than the 3-jaw chuck; but I think I prefer the setup. Thoughts? The only issue is the amount of overhang, it would be great if you could get the collet a lot closer to the headstock. |
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Post by runner42 on Nov 16, 2018 7:01:40 GMT
Hi Lisa,
the only thought that I had was because the drawbar is not long enough to engage the MT3 in the same manner as when fitted to the mill, it is only the MT3 taper that is keeping the whole setup in position. If the tapers in the lathe and collet chuck is very good it should stay there. but if not the whole setup could go to the right. Suggest you conduct a dummy run to see if it holds. Good luck.
Brian
PS I speak from experience having tried the same setup in my old Southbend lathe where the taper in the headstock is very poor when I tried to undertake the same machining operation it did go to the right. I overcame this by producing a collet chuck connected to the spindle, but that is not on your list of things to do, I daresay.
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Post by Rob on Nov 16, 2018 9:34:50 GMT
I tried a similar set up in my lathe recently to make my crank pins, but found that it wasn't rigid enough so I ended up with chatter marks. I tried a variety of feeds and speeds to try to get around it, but in the end I reverted back to the three jaw. Admittedly I was cutting silver steel which may make a difference.
I would like a lathe mounted ER32 collet chuck, was hoping I wouldn't need one with that set up!
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Lisa
Statesman
Posts: 806
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Post by Lisa on Nov 16, 2018 18:45:28 GMT
Milled out one of the exhaust cavities this morning, and finished the valve to length; one down one to go.  I need to grind up a thread cutting tool for the piston rod, so I'll ponder the setup for that for a while. |
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Lisa
Statesman
Posts: 806
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Post by Lisa on Nov 17, 2018 21:26:44 GMT
The two newly ground tools got put to use this morning, first cutting a thread into the piston rod (M8x1.0), then facing the piston to length and turning it down to size. I ended up holding the piston rod in the 3-jaw rather than the collet chuck as it was closer to true!   Still a couple of millimetres to come off the diameter here, then the slot for the piston ring needs to be cut in. |
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Post by simplyloco on Nov 17, 2018 21:29:19 GMT
Good to see a fellow ME utilising 'cutting edge' technology!  John |
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Post by Jim on Nov 17, 2018 21:57:45 GMT
Agreed John. Jim the Luddite  |
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Post by David on Nov 18, 2018 21:48:06 GMT
Nice work, looks great! I'm surprised the 3MT collet was further out than the 3-jaw - makes you wonder if your milling cutters only cut with one flute. That might explain why my small cutters seem to cut so oversize sometimes.
Did you finish the thread with a die? If not, very impressive. Valve looks good too.
I don't know if the Blowfly instructions suggest loctite for the pistons but it seems to be a good idea - my father-in-law had one unscrew once. Afer you're happy with the length of the piston rod of course. I can't remember if I put it on mine now.
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Lisa
Statesman
Posts: 806
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Post by Lisa on Nov 18, 2018 23:19:04 GMT
Nice work, looks great! I'm surprised the 3MT collet was further out than the 3-jaw - makes you wonder if your milling cutters only cut with one flute. That might explain why my small cutters seem to cut so oversize sometimes. Did you finish the thread with a die? If not, very impressive. Valve looks good too. I don't know if the Blowfly instructions suggest loctite for the pistons but it seems to be a good idea - my father-in-law had one unscrew once. Afer you're happy with the length of the piston rod of course. I can't remember if I put it on mine now. Thanks David, I suspect the main issue is the bearings on the lathe spindle which are unloaded parallel rollers and known to cause inaccuracies as a result; eventually I'll replace them with loaded thrust bearings, but for now oddities like this will show up. I didn't finish the thread with a die, mostly because I don't have an M8F die; building up a set of metric fine taps and dies is on my list of tools to eventually get. The Blowfly instructions don't say to use loctite, just tighten it rather aggressively, which is what I've done. If it's ever problematic I'd likely bore out part of the piston and fit a lock nut; I've done that before, and thought about doing it here, but didn't simply because all the other Blowflies seem to do alright. We shall see. Anyway I finished one piston this morning, It's a couple of thou smaller than the cylinder bore so slides through nicely. The parting tool chattered a bit on the grove for the ring, but it worked out fine.   With the ring on, and oil everywhere, it's quite tight in the bore, but I can just move it back and forth by hand, so I'm quite happy with the fit of everything. |
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Post by Roger on Nov 18, 2018 23:28:53 GMT
A great result as usual. Thinking about the Metric Fine threads, you could always buy a tip tool holder and just buy one or two inserts. Quite a lot of the threads are 0.5mm pitch so you can screw cut them without spending out on dies.
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Post by David on Nov 19, 2018 1:20:13 GMT
Did you screw cut the internal threads in the piston or do you have a tap?
Who cares about chatter on the bottom of a piston ring groove? You'll never see it again. What technique did you use to put some spring in the ring? I went with a piece of metal in the gap while heating and that worked well.
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Lisa
Statesman
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Post by Lisa on Nov 19, 2018 9:42:29 GMT
I've got a tap, so no internal thread cutting. I was trying to remember what I bought it for earlier, but I still haven't a clue.
My method for the rings was to buy them, several years ago, which simplified things muchly.
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