There is a common mistake made by newbies on the 7x12minilathe yahoogroup when it comes to cutting threads. A common threading approach is to angle the compound slide over to 29.5 degrees (some folks just go 30). However, the degree scale on the lathe is set to reference as 0 degrees what SHOULD be referred to as 90 degrees when it comes to cutting threads.

 If someone is not aware of this 0 = 90 on the scale when they go to cut threads, they will naturally enough rotate the compound slide to what the scale indicates is 29.5 degrees. Since in this case 0 = 90, what the angle actually comes out to is 90 - 29.5 = 60.5 degrees. This will make for some seriously mangled metal instead of workable threads! Here is the common mistaken WRONG way that causes so much trouble when they're just learning this for the first time:

If you look real close you can just make out that the built in angle scale is on 29.5. This is the common error that catches so many people off guard. This is actually 60.5 degrees!

 Here is the RIGHT way to do things. First off, IGNORE the built in angle scale. I use a protracter that I picked up cheap at Harbor Freight. Here it is set to 29.5 degrees:

 I hold it along the left side of the compound, with the numbers/text facing down, using the cross slide as a reference, and align the compound slide to match the perfect angle.

 Here is the CORRECT 29.5 degree angle set up for threading properly:

 Note how the angle setting is completely off the scale. If it would read as high as 60.5 and it was an accurate scale I could use it by setting for 60.5 to get the required 29.5. The protractor is far more accurate in any case.

 So here is the WRONG picture again, close together with the above CORRECT setting, so you can compare them. :-)
 WRONG WRONG WRONG WRONG WRONG WRONG WRONG!


 So the moral is, do not trust the built in angle scale. At best it is only good for when roughly close is good enough... and 0=90 in the case of thread cutting. Use a protractor!

 That's it..!
 John Z.