# Ferrobob



## cathead (Mar 4, 2021)

This morning for a bit of shop fun I decided to make a plumb bob.  I had some left over
tie rod ends that needed to be something else so made the ferrobob out of part
of a tie rod.  I used the compound and machined on the back side of the part
using the lathe in reverse, something I hadn't done for a while.  It worked just fine.  



I made the ferrobob out of the threaded end of the tie rod end as it was the only straight part.  It machined pretty well so apparently
the tie rod ends are not too far from mild steel.


I have been thinking of using a plumb bob as an aid to lathe leveling.  Now all I need is a stand to hold up the plumb bob and a piece of fishing line.


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## Braeden P (Mar 4, 2021)

smart putting your lathe in reverse to cut the taper


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## brino (Mar 4, 2021)

@cathead 
Your knurls look perfect!
Nicely done.
-brino


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## cathead (Mar 5, 2021)

Just for fun I welded a 1/2 inch bolt to a piece of cold roll and rigged up a stand to see if my lathe was anywhere in the realm of level.
I was surprised that seemingly is close on.  I do have a mechanics level but it has been several years since I have checked for level.
I will do a little comparison work and see how they compare.  It's an old and somewhat worn lathe from the 40's.  It's entirely possible
that the lathe would be more accurate off level I suppose.  Even with significant wear, if one knows its defugelties, a person can do
accurate work.  
	

		
			
		

		
	




	

		
			
		

		
	
 If I get serious with this plumb bob leveling, I will glue on a small ruler on the base.  The base, by the way looks a little rough so I put the
best side down and used a diamond hone to stone it off to be flat within reason.  It could be put on a surface plate and scraped if one were to be looking for real accuracy.  Next I will see what the machinist level has to say about this......


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## Shotgun (Mar 5, 2021)

As long as the plumb bob indicates to the same point, does it really matter if the top of the base is smooth or flat?  I would be more concerned with the bottom.  A bump there could throw everything off, depending on how it lands on your blocks.

How do you check your machinist level, other than finding a level spot, flipping the level 180, and verifying that the same spot is still level?


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## cathead (Mar 5, 2021)

Shotgun said:


> As long as the plumb bob indicates to the same point, does it really matter if the top of the base is smooth or flat?  I would be more concerned with the bottom.  A bump there could throw everything off, depending on how it lands on your blocks.
> 
> How do you check your machinist level, other than finding a level spot, flipping the level 180, and verifying that the same spot is still level?


I stoned the bottom of the base.  When using the machinist level I will have to stone both sides of the bar if I elect to use
the one with the string level.  The top is acritical using the string.


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## cathead (Mar 7, 2021)

Using the plumb bob method of leveling, I was able to determine only one thing and that was that both readings were the same.  
After using my machinist's level I found that part was true but the lathe was far from level.  It was high in the front by a fair amount
for some reason so now I have more leveling work to do using the machinist level.  Maybe the garage floor is sinking by the wall....


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## Shotgun (Mar 7, 2021)

Did you know that seamen are able to use lathes on ships which are rocking back and forth?

The bed doesn't have to be perfectly level, and it won't know if you don't tell it.  The bed could be vertical and the lathe would work exactly the same.  "Level" is just an easy indicator in order to get what you got from the plumb bob. . .that both ends are the same.


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## rwm (Mar 7, 2021)

Nice piece. What is the advantage of cutting on the back side of the part using reverse? Why not just use the compound in conventional fashion?
Robert


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## cathead (Mar 7, 2021)

rwm said:


> Nice piece. What is the advantage of cutting on the back side of the part using reverse? Why not just use the compound in conventional fashion?
> Robert



It was just ergonomics as it was easier to rotate the compound to reach the back side, just my way of doing things
being Norwegian and all.


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