MATH Formula for figuring 1000ths into degree's

JPigg55 said:
Might be easier to see if you can find a new indictor dial for your machine.
What machine you got ??? I don't mind helping you look, I'm always surprised at what I run across while browsing.
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mines a 1946 sheldon and the degree's is cast into the compound base the only other way i see of doing this is maybe degree tape the kind you peel off the back then stick it to the compound base. ty:)) mac
 
Do you want this fine degree of rotation to be useable throughout the entire rotation or just for a small defined portion thereof?

Gene
 
As Tony Wells said any movement will create errors, the "degree tape" may work but getting the exact distance for the divisions may be tricky. If you could mount the compound in an indexer you may be able to remark the compound by inserting a well sharpened cutting tool in each mark and pulling the tool through the mark. There was a thread on using this method to mark new dials when upgrading a lathe about a year ago.

Have to go now will watch for the thread.

Ray
 
Set the dial indicator up so the point is on the compound, and the base is attached to the carriage (tailstock side). I think this is what you are asking about. The easiest way to do this is if you place a small block on the compound so that the face of it is on the center line, then put the tip of the indicator on the block. If M is the reading of the dial indicator, and H is the distance between the compound pivot and the indicator tip, then the angle is "arctan(M/H)". You can look this up in a table, but easier yet is to get a simple scientific calculator (assuming you don't already have one).

If you instead want to know what the indicator reading should be for a given angle it's just as easy, lets call our angle "Phi". Then the indicator reading you want is going to be given by M=H*tan(phi). Again, the value of tan(phi) can be looked up, or use a scientific calculator.

This method is probably only going to work for about 45degrees, after that you are going to run out of indicator room, but since you are probably dealing with angles less than that most of the time, it should work ok.

di_to_compound2.png
 
DMS said:
Set the dial indicator up so the point is on the compound, and the base is attached to the carriage (tailstock side). I think this is what you are asking about. The easiest way to do this is if you place a small block on the compound so that the face of it is on the center line, then put the tip of the indicator on the block. If M is the reading of the dial indicator, and H is the distance between the compound pivot and the indicator tip, then the angle is "arctan(M/H)". You can look this up in a table, but easier yet is to get a simple scientific calculator (assuming you don't already have one).

If you instead want to know what the indicator reading should be for a given angle it's just as easy, lets call our angle "Phi". Then the indicator reading you want is going to be given by M=H*tan(phi). Again, the value of tan(phi) can be looked up, or use a scientific calculator.

This method is probably only going to work for about 45degrees, after that you are going to run out of indicator room, but since you are probably dealing with angles less than that most of the time, it should work ok.
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ok understand i will do some figuring on this and see if thats the route i wanna take, i even thought about useing a protracter with arm on it and hold it up against the cossslide and the arm on the compound that way when moved it will give the degree again after i try cleaning and painting the degree increments:)) mac
 
Honestly, most of the graduations on compounds aren't all that precise anyway. If you want to get the angle very close, you simply indicate it in according to the indicator drop over a given distance of travel. So I'd go with the remarking of the existing grads, paint them and use them to get close, and if I needed precision, get out the indicator and use the sine method.
 
Tony Wells said:
Honestly, most of the graduations on compounds aren't all that precise anyway. If you want to get the angle very close, you simply indicate it in according to the indicator drop over a given distance of travel. So I'd go with the remarking of the existing grads, paint them and use them to get close, and if I needed precision, get out the indicator and use the sine method.
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understand tony, going to work on lathe tomorrow since its going to be nice, going to try and wire brush the increments and try painting to get them to show up better, hoping they will but again ty:)) mac
 
You all know I hate math. A 1946 Sheldon. A 1946 S. Bend. Anyone know what a 1937 or so
Hudson Terraplane looks like. Absoulutly no place to set your beer can on. Same thing with
those lathes back then. Just no place for dial ind or magnets everythings round or art deco.
And the on S Bends the degrees are on the back side and so small I cant read them even it
they were on the front side. So you have to get a little creative. Best I can put into words will
be quick & easy no math--try and paint this picture, I will put a dead center in the headstock
this will be a witness mark, remove the toolpost. I then made a precision alum block in the
shaper that fits the compound toolpost as a riser (the height of the witness mark (center)
a quality round clear protractor on the riser. These or atleast mine has a bar thats exactly
90* to 0*. At this point the protractor reads 270* so the compound is dead "0". Again hating
math I slotted this riser 90* on the shaper so the protractor's bar fits the block and now
the dead center W.Mark reads "0". Now with much effort with mirrors spy glasses to verify
the compounds "0" with the protractor, which I got dead on. I do know the protractor is
LS Starrett around 1960 (i took it from HS drafting class now past the 7yr clause) . Then
ya got no shaper, then just turn one with a four jaw. NOTE keep in mind using this method
that you have to start off with the compound on dead center I mean the protractor on
center when rotated which is easy to dial in. Best I can type. sam
 
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