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Post by Deleted on Dec 19, 2009 18:56:43 GMT
Four Jaw Chuck is King OK!Now I have this exalted rank I will now attempt to persuade some newbies (and some oldies, perhaps) that they don't need to spend money on a big milling machine and its accompanying DRO! This is a tongue in cheek thread so don't take me too seriously!I am merely exploring/showing the versatility of the lathe. The lathe with its 4 jaw chuck is probably the most powerful milling machine in some workshops. You don't need parallels, packing pieces, edge finders or other more sophisticated gadgets. As an example here I'm making a 1 1/4" square poppet valve regulator using only the lathe and no castings. I'll do it separate posts as it's a bit fiddly, but it would be much the same on alternative equipment. This afternoon's work was to make the block out of a piece of rough sawn bronze I just happened to have lying around! At £30 a pop for the Reeves casting I can handle a bit of waste! It was too big, so it felt like Popeye's Cufflink Works for a while, but I got there. First up, get the biggest face true: you don't need to centre the block. Second, machine the other side to size. The good face is hammered tight up against the chuck face. The idea is to obtain two master sides absolutely parallel. First face: YES, It's a carbide, I'm not a masochist.....  When that is done you can clamp it up using brass shims and machine the other faces square thus:   Turn it over and machine the end face. This regulator will have a boss on one side and that face will be machined off later after marking out.  Part it off; Yes, that's what I said......  OK, I didn't part it right off.....it was prudent to hacksaw the last bit  Block back in the chuck and faced off to size.  This job took about an hour, and I can assure you that was quite straighforward. Ill mark it out and do the fiddly bits in the next few days: watch this space! JB
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Smifffy
Statesman
Rock'n'Roll!
Posts: 943
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Post by Smifffy on Dec 19, 2009 20:53:20 GMT
These are great postings JB. It's always good to see how other people do "stuff".
My afternoon was spent turning my last crank pin and then scratching my head thinking about the hell I'm going to Third (as opposed to quarter) the wheels on my Royal Scot. After a bit of playing around with the lathe I decided on making a jig. Fingers crossed, it'll be done tomorrow.
Keep your posts coming!
Mark
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Post by Deleted on Dec 19, 2009 21:16:34 GMT
Hi Mark, I made a jig to 'Quarter' my wheels but I have no idea how to do a 'Third'!
On the the subject of stuff, I might just introduce a few old fashioned techniques such as Toolmakers' Buttons (pre DRO) to do the holes for the poppet valves! This level of accuracy is not necessary, but it'll be a bit of fun!
JB
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Post by Deleted on Dec 20, 2009 15:44:43 GMT
Button BoringThis is a technique that we used to use before those expensive electronic DRO gadgets arrived! Buttons are positioned on the piece to be machined using slip gauges, in the places where holes are required. Each button is set up to run true in the lathe, the button removed, and the hole bored to size. Done properly, positional accuracy of +/- 0.0002" can be achieved quite easily, although I couldn't do it now! This regulator block requires two parallel holes, tapped 3/8" x 32 ME by 3/8" deep, both reamed or bored 3/16" and 7/32" respectively to accommodate the poppet valves.  Hopefully the picture is self-explanatory, the block was drilled and tapped where the holes are required, and 1/4" hollow 'buttons' held lightly in place with, appropriately enough, button head screws. It's simple arithmentic to calculate the required gauge dimensions, although with small buttons such as these it's a bit tricky to hold them in place whilst tightening up. If you were really serious the piece would be held against the 3-2-1 block with a toolmaker's clamp. The piece is put back in the lathe, set to run true roughly by eye, and trued up using the DTI. I set this to a total runout of 0.0003" as any closer would be quite unnecessary!  Button removed and a small bore (Not Paul Daniels I hope!) started to get rid of the 2.5mm tapped thread and to provide a start for the drill, as you can use one to get rid of bulk material before finish boring.  The hole bored 8.8mm for 3/8 x 32 ME. The use of a small boring tool enabled me to machine a flat face at the bottom of the hole at precisely 3/8" deep, and go on to bore the 7/32" hole for the poppet valve. I'll tap it and repeat the ops for the other hole.  Second hole completed. They are in-line to within 0.00025", measured from the sides. Just shows what can be done with primitive, old fashioned equipment.......  That's button boring. It's much easier to do this job on a Jig borer or precision milling machine, but if you ain't got either, the lathe is a jolly useful alternative, and shouldn't be forgotten or ignored. To be fair, if you are confident in your centre -popping, this piece could have been set up using the 'waggly pin in the tailstock chuck' method instead of the buttons, but this was opportunity to show an alternative method. Try this at home, it's quite safe.....JB
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Smifffy
Statesman
Rock'n'Roll!
Posts: 943
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Post by Smifffy on Dec 20, 2009 20:09:31 GMT
..fascinating! I had to read through a few times before it all made sense.
Keep them coming :-)
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davidm
Seasoned Member
Posts: 109
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Post by davidm on Dec 20, 2009 20:50:15 GMT
A picture (or several) is worth a thousand words. Thanks for making clear a method that I've read about but couldn't quite get the hang of.
For those of us with no engineering background, (I hadn't even used a drill press let alone a lathe before I started to build my Simplex), things like this are just the ticket.
Thanks,
David
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Post by Shawki Shlemon on Dec 21, 2009 8:18:35 GMT
Hi JB Have you been an instructor or teacher sometime in your life , you are doing a very good job of it , congratulation and thank you , keep up the good work .  |
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Post by drjohn on Dec 21, 2009 8:40:31 GMT
Very instructional JB, but I gotta say that I would just stick the lump in the vice on the mill and count the turns - an awful lot easier.
After all, in the olden days we also had steam trains that worked - now we have super-dooper electric eurostars that don't ! ;D ;D ;D
DJ
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Post by Deleted on Dec 21, 2009 9:27:34 GMT
Very instructional JB, but I gotta say that I would just stick the lump in the vice on the mill and count the turns - an awful lot easier. After all, in the olden days we also had steam trains that worked - now we have super-dooper electric eurostars that don't ! ;D ;D ;D DJ I don't disagree DJ, as stated in my post, but unlike many, you are fortunate in having a big chunky mill to count the turns on! Regarding the trains, it appears to have been the wrong kind of snow... JB Good luck with the B5, and the video was great. |
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Post by Deleted on Dec 21, 2009 16:14:30 GMT
Finishing the Regulator BlockThe drawing specifies a cavity underneath to accommodate the actuating lever, and this was machined out from the solid. If more space is required in the corners on assembly then I'll 'Dremel' it. I could have stuck a hollowed 3/8" thick block underneath and silversoldered it, but after my recent experiences......  Next job is the boss to take the actuating shaft. It is reamed thru 1/8" and tapped 1/4" x 40. This was set up using the waggly pin in the tailstock approach mentioned yesterday. If you've got an optical punch outfit (which I must get sometime) you'll be pretty close to the buttons in accuracy.  Finished boss.  Finished regulator block and distance piece which connects it to the smokebox tubeplate. The cross drilling was a nightmare; a real heart in the mouth job!  Poppet valves next. Stainless or drawn bronze? The bronze will certainly be easier to machine! JB
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Post by bigt1677 on Dec 22, 2009 10:04:35 GMT
beautiful job JB , as always..........
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Post by drjohn on Dec 22, 2009 13:44:44 GMT
First face: YES, It's a carbide, I'm not a masochist..... Almost missed that JB as it was so near the picture - and wasn't it your good self giving me a bollocking for using carbide when I should have used HSS?? ;D ;D  DJ |
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lancelot
Part of the e-furniture
Posts: 471
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Post by lancelot on Dec 22, 2009 15:25:40 GMT
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Post by Deleted on Dec 22, 2009 17:09:36 GMT
Thanks John, I've just had a look and it might be just the job! JB |
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Post by Deleted on Dec 28, 2009 12:49:34 GMT
I managed to sneak a few hours in the workshop yesterday, so the regulator is finished. I haven't photographed the making of the poppet valves, as it is just straightforward turning, if a bit fiddly. The valves have been ground in: reminded me of my youth and MG Midget cylinder heads! All I have to do now is assemble and pin it so the the smaller valve opens fractionally before the big one....... JB  |
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