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RussZHC
08-03-2011, 09:40 PM
First a big thanks to all who contribute here, continually learning.

Satisfying day today, got the lathe more or less completely assembled (all except back gear, still have to remake a couple/three teeth but that is well on its way too). AND, first chips :D .

All things considered, very late 30s Sheldon 10" lathe, I think I will be happy with the choice. Only real role is as a learning tool. Of course have my eye on something much "more" and only about 10 years newer.

Also satisfying in that it now feels a bit more legitimate participating in this forum, granted early days.

Eyeballed the grinding of the bit, free handed the top and tweaked the sides a little, mostly putting a bit more of a "polish" on the stock grind http://bbs.homeshopmachinist.net/showthread.php?t=49197.
First attempt was not good, cutting but a spiral pattern, tightened up the adjustment on the end of the spindle (screw on collar) and appears to have been mostly solved.
Second attempt much better but chips small, almost crumbly, little colour.
Third attempt, refined the finish of the cutting tip/edge, upped the feed a bunch. :D :D :D Spirals about 1/2" diameter, about a dozen loose loops in a row before it would break off, whole length a medium gun metal blue.
Finish was not good but was not expecting glass smooth as the tool grind I was trying to get was as a roughing tool (definitely put a radius on it!).
Some taper BUT I am thinking more having to do with the spring in the work piece which started out at 3/4" and last pass gave me a tick more than .6"...about 6" sticking out of old Cushman 3 jaw with no support on "free" end.
Belt will squeal/howl then slide before the motor will stall, so...

Black_Moons
08-03-2011, 09:45 PM
Sounds like a good day! And yea, roughing passes are never about accuracy (or good finish), Just about getting metal outta your way!

It will be the finishing passes where you put the accuracy and quality surface finish into your work.

Hal
08-04-2011, 11:05 AM
Russ

I think the rule of thumb is no more than 5X's the diameter of the work sticking unsuported out of the chuck.

Hal

davidwdyer
08-04-2011, 11:17 AM
Woah! Is that so??

I thought I was told only one and a half times the diameter.

firbikrhd1
08-04-2011, 11:29 AM
Woah! Is that so??

I thought I was told only one and a half times the diameter.


That is what I have learned too.

Black_Moons
08-04-2011, 02:12 PM
5 diamiters seems a much better rule of thumb to me. You do have to start taking careful cuts with that much cut out if the work is kinda thin compaired to the DOC your taking.

Longer can be done, but you really start risking the work rolling over the tool with deeper cuts (or perticularly facing)

1 1/2x diamiter is probley a better rule for heavy facing operations for example. Or an absolute limit for cutoffs (really should be done closer to the chuck then that)

RussZHC
08-04-2011, 10:02 PM
Thanks Hal.


...really start risking the work rolling over the tool with deeper cuts

Glad to know the reason as well, makes perfect sense. AND I was sort of wondering when I would do something with that "RISK" word in it.:o

Tweaks the order of what I was going to do next...finish tailstock repair, get moving on those steady and travel rest projects (as purchased it came with neither rest)