NSA Needing Some Advice

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51Echo

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I am wanting to shave an 1/8 inch thickness off the ends of 1 inch thick solid rods - I'm trying to make plugs to fit into chrome molly tubing - I don't really know how to describe in words what I want to do, but here goes: I want to stretch a motorcycle frame - so I'll cut the down tube and place a 6" piece of solid rod (same diameter as frame) between the two pieces (thereby extending the frame) - I was hoping to reduce both ends of the solid rod so that they will insert into the frame tubes at least 2 inches (I could then drill and plug weld).

I assume I will need a lathe to do this... if so what is the best type (model) or style of machine to do this? Are there affordable lathes available for the "backyard" machinist? I realize I could take my projects to the Machine Shop - but here I have an excuse to buy some new or used equipment (you know what I mean).

Any help would be appreciated.

Ed
 
Hate to put a crimp in the lathe idea, but why not do what they do to repair damaged sections of tube in rag-&-tube aircraft. Insert short telescoping sections of tubing inside both ends of the extension and original tube. Many examples of how to do this on the internet and in aircraft construction/repair books. Other than cutting tubing, no real machining required. Bet this is how professional bike shops do repairs and mod's.

Ken
 
sounds like you want to buy a lathe. in this crazy hobby, its is most always said to " buy the biggest you can afford and have space for". i have a old 12" craftsman that would do the job standing on its head. probably another one like it could be had for a grand or maybe a bit more. is you bike frame "seamless" or does it have a welded seam on the inside. if it is seamless, the chore will be pretty much straight forward. so go for the lathe.. .. .. .. and make chips and swarf "till the cows come home" (so to speak)

there will be plenty of responses about what to buy, and whats available to you wherever you are.

come on guys, tell him what to buy. . . . . . :)
 
Typically for choppers they do turn down a piece on the lathe. In a pinch you could also use a grinder. It will take a long time and won't be as pretty as whats done on the lathe. But it would work.
 
If you choose not to use swaged tubing but instead to go with solid rod... you COULD do that job with any of the cheapie $300 7x10, 7x12, or 7x14 minilathes from any of about a dozen different manufacturers (they're all pretty much the same except for screw pitches & accessory details).

You'd start with round rod a little larger diameter than you really want, center-punch both ends, and turn one stepped end between dead center in the headstock, driven by a lathe dog attached to your faceplate, & live center at the tailstock. Flip the workpiece, turn the other stepped end and the OD, now between chuck & live center (or between dead center/faceplate/dog and live center). The reason you'd start oversize is... you CANNOT accurately center-punch the ends, so when you first turn it, it'll be a little eccentric. As you turn it, the OD will turn to being exactly parallel to an imaginary line between the two center-punch marks. It's crucial to turn it between centers for the first cut or two, until you have an OD that's concentric with the centerpunches.

If you used a little bigger lathe, you could insert the round rod through the chuck, all the way back up inside the hollow spindle (takes a fairly good-sized spindle for this), and center-drill both ends. That's not as accurate as turning oversized stock between centers, but it'd be plenty accurate enough for this job. It WOULD require a couple thousand extra dollars of outlay for the larger lathe, though - one that could pass 1" stock through the spindle bore.
 
davidh said:
sounds like you want to buy a lathe. in this crazy hobby, its is most always said to " buy the biggest you can afford and have space for". i have a old 12" craftsman that would do the job standing on its head. probably another one like it could be had for a grand or maybe a bit more. is you bike frame "seamless" or does it have a welded seam on the inside. if it is seamless, the chore will be pretty much straight forward. so go for the lathe.. .. .. .. and make chips and swarf "till the cows come home" (so to speak)

there will be plenty of responses about what to buy, and whats available to you wherever you are.

come on guys, tell him what to buy. . . . . . :)
Click to expand...

Hey David - you saw right through that hey? Most frames are seamless but there is the odd exception... thanks for the heads up regarding the 12" Craftsman.

Ed (sorry for the delay in responding my internet was down....
 
JoeSixPack74 said:
Typically for choppers they do turn down a piece on the lathe. In a pinch you could also use a grinder. It will take a long time and won't be as pretty as whats done on the lathe. But it would work.
Click to expand...


Hey Joe - you are right a grinder could be used in a pinch - but the frames I'm working on are not a "rush" job so thankfully I can wait a bit - I could if in a panic take it to a machinist - but I'm hoping to do multiple frames - so a lathe might be a fun - a good thing to have in the shop.

Ed (sorry for the delay in responding my internet was down....
 
TDHofstetter said:
If you choose not to use swaged tubing but instead to go with solid rod... you COULD do that job with any of the cheapie $300 7x10, 7x12, or 7x14 minilathes from any of about a dozen different manufacturers (they're all pretty much the same except for screw pitches & accessory details).

You'd start with round rod a little larger diameter than you really want, center-punch both ends, and turn one stepped end between dead center in the headstock, driven by a lathe dog attached to your faceplate, & live center at the tailstock. Flip the workpiece, turn the other stepped end and the OD, now between chuck & live center (or between dead center/faceplate/dog and live center). The reason you'd start oversize is... you CANNOT accurately center-punch the ends, so when you first turn it, it'll be a little eccentric. As you turn it, the OD will turn to being exactly parallel to an imaginary line between the two center-punch marks. It's crucial to turn it between centers for the first cut or two, until you have an OD that's concentric with the centerpunches.

If you used a little bigger lathe, you could insert the round rod through the chuck, all the way back up inside the hollow spindle (takes a fairly good-sized spindle for this), and center-drill both ends. That's not as accurate as turning oversized stock between centers, but it'd be plenty accurate enough for this job. It WOULD require a couple thousand extra dollars of outlay for the larger lathe, though - one that could pass 1" stock through the spindle bore.
Click to expand...


My desired direction is round stock - so a lathe - thanks for advice - so since I posted this question something neat has begun - a local mechanic heard I was looking for a lathe and asked if I'd be interested in an older model lathe - I said sure but asked about the price - he said you pay for the shipping from Vancouver and its free - He knows nothing about size, power, type, age or weight - but thought it may be 500 to get it here.... Its like Christmas... I will let you know when it comes in... I'm hoping to do multiple frames - so a lathe might be a fun - a good thing to have in the shop.

Ed (sorry for the delay in responding my internet was down....
 
Hawkeye said:
Ed,Kind of depends on your budget. Here's one on Castanet. http://classifieds.castanet.net/details/metal_lathe/1553652/Been listed for a couple of weeks. I'm not familiar with this brand, but I could meet with you if you were going to check it out when I'm not tied up.Another option is to check out KMS Tools in town here. They have a good selection, which you can view at http://www.kmstools.com/
Click to expand...


Hey Hawkeye (my internet was down ;-( sorry for the delay)

thanks for advice and offer to look at one with me - that would be much appreciated. But since I posted this question something neat has begun - a local mechanic heard I was looking for a lathe and asked if I'd be interested in an older model lathe - I said sure but asked about the price - he said you pay for the shipping from Vancouver and its free - He knows nothing about size, power, type, age or weight - but thought it may be 500 to get it here.... Its like Christmas... I will let you know when it comes in... I'm hoping to do multiple frames - so a lathe might be a fun - a good thing to have in the shop.
 
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