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vnygra
03-24-2014, 7:16 PM
Was thinking we could have a sort of "catch all" for different lathe tricks people use on their machines.

Heres one i found while looking for a new chuck for my 13'' south bend, since it was 70+ years old and had gotten around +.015 run out, which sucked unless you were taking a lot of metal off, or didn't need to take out and move the part a bunch. I dealt with it for a few years.... This actually worked really well, took about a half hour using a diamond grinder i got at the hardware store for $10. Got the chuck down to .003 runout, not bad for a 3 jaw
http://i940.photobucket.com/albums/ad250/vnygra/20140322_203932_zpsujy1jxsq.jpg (http://s940.photobucket.com/user/vnygra/media/20140322_203932_zpsujy1jxsq.jpg.html)

i have a few pics of a nice tubing notcher attachment i made up too but dont have pics of it right now, will edit this when i get them up.

thatcher
03-29-2014, 1:28 PM
http://www.thatcherworks.blogspot.com/2012/03/tube-mitre-lathe-attachment.html
turn your lathe into a tubing notcher

Chevota
03-29-2014, 3:16 PM
Great tip on grinding the jaws. A guy on Youtube named Tubalcain (mrpete222) did the same thing in a recent video of his. Thanks for sharing.

patdoody
03-30-2014, 7:58 AM
Great tip on grinding the jaws. A guy on Youtube named Tubalcain (mrpete222) did the same thing in a recent video of his. Thanks for sharing.

I love his vids. That dude is a wealth of knowledge. I just bought a 40.00 dremel from lowes the other night to do this to my 3jaw that came with my harbor freight 9x20 I use.

Krutch
06-28-2015, 6:13 PM
Most chucks won't run true throughout the range due to the wear in the scroll that engages the back side of the jaws. Plus one should brace the jaws to close or open depending on ID or OD grinding. The ground jaws will be good for the size you grind them to but may not be at other sizes. If one has two piece jaws, blank soft top sets are a better buy.

DustyDave
06-28-2015, 6:43 PM
If you drill and tap holes in the end of the jaws then put screws in the jaws you can clamp the ring on the inside of the screws. This loads the jaws in the position they will be in when clamping. The way Vnygra showed it would be the setup for grinding the outside of the jaws.
I have clamped a washer at the very back of the jaws and ground up to the washer then moved it to the front ams worked through the hole in the washer to finish the back. But its a lot more fiddly and a few holes in the end of the jaws doesn't dif me no makerance.
Dusty

GaryC58
06-28-2015, 8:08 PM
I have never run a lathe,but that's about to change.
Class starts on July 14th at my local community college,and I am ready.

fullercnc
06-29-2015, 5:35 PM
Most chucks won't run true throughout the range due to the wear in the scroll that engages the back side of the jaws. Plus one should brace the jaws to close or open depending on ID or OD grinding. The ground jaws will be good for the size you grind them to but may not be at other sizes. If one has two piece jaws, blank soft top sets are a better buy.

+1 to that very good advise. For an at home machinist, use your hard jaws for all your multipurpose work and parts where your not having to skim diameters. Buy some soft jaws for when have to take skims cuts to clean up a bore or something. When you put the soft jaws on a bore them, you should have .0005" to .001" run out. Soft jaws are a life saver when trying to do something true something up and have it concentric.

Krutch
07-04-2015, 11:42 PM
+1 to that very good advise. For an at home machinist, use your hard jaws for all your multipurpose work and parts where your not having to skim diameters. Buy some soft jaws for when have to take skims cuts to clean up a bore or something. When you put the soft jaws on a bore them, you should have .0005" to .001" run out. Soft jaws are a life saver when trying to do something true something up and have it concentric.

One other idea is a Set-True chuck. The body holding the jaws is adjustable to a certain degree. One can clamp a round in the jaws and move the body to dial in the work to run true. Draw back is you have to buy such a chuck and possibly a mount for the spindle. I did over a year ago and it has been a plus for what I do around here. I also have some blank soft jaws for special runs of work.

Krutch
07-05-2015, 12:28 AM
While setting up the job, set the compound at 2 to 5 degrees to the spindle line. Compute the angle to find how much the tool advances towards the centerline as it moves towards the headstock.
As in .005 @ 2 degrees =.00017" So with the compound set to 2 degrees from parallel to the spindle axis for every .005" movement the tool moves .00017" towards or away from the work depending on how you set up.
You can set the compound at any angle and figure the infeed per dial feed and get much closer than by guessing a direct infeed. You only have to keep in mind the headstock movement if there is a shoulder or other feature to avoid hitting.

Say you set the compound at 5 degrees from the axis to figure movement formula is C x sin D C is compound movement times the sin 5 degrees or .005" times .087155743 = .000435779" infeed.
you can set the compound angle then figure the infeed as you need. Draw a right triangle to help visualize the travel. Side a is the infeed to the material side c or hypotenuse is the compound feed. Find the sin for the angle and compute side a's movement per side c's feed.

For example 6 degrees from axis = .00052" for .005" travel of the compound slide. That is just over one half of a thousandth infeed. After getting used to this procedure you can turn work to with-in a gnats ass. Let the gnat wipe his own ass by the way.
Don't forget to allow for material removal from the work. Different lathe dials read for tool feed or material removal.
Some dials read one dial mark is one thousandth off material and some read one mark is .001" movement of the tool as in .002" off the work. The compound is most often tool movement or .001 in = .002" off work. If you are not sure do a tryout before committing material you can't afford to waste.

GaryC58
08-14-2015, 8:37 AM
We had our last class yesterday evening.
Had to rush like a mofo just to get my aluminum hammer completed,so the finish etc. isn't perfect.
But I can tweak it at home and make it better.

Freewheeler
08-14-2015, 9:30 AM
We had our last class yesterday evening.
Had to rush like a mofo just to get my aluminum hammer completed,so the finish etc. isn't perfect.
But I can tweak it at home and make it better.

That brings me to my number tip for a lathe and actually, any machining process - you cant hurry metal!

Nick

GaryC58
08-14-2015, 2:20 PM
From my extremely limited experience,I completely agree.
The metal looked better when cut at a slower speed and a shallower cut,from what I could see.
It annoys me because we spent too long doing it in plastic first.We already had gotten the point.
Should have had two class periods to do our hammer,not one.
Especially when you consider the time wasted in the earliest classes,when we didn't stay long.
I wanted mine to be perfect,but given the situation,just didn't have time.