# Next Project: Fly Cutter



## Maddogmech1 (Mar 24, 2015)

After completing my steady rest, I had a longing to make more of a swarf mess all over my shop, so I decided to upgrade my fly cutter set. I purchased the set from littlemachineshop, it was, in fact, the first tooling I bought after getting my mill, and I was very underwhelmed with the results. I couldn't seem to get a good finish no matter what I tried, but figured it was my lack of experience. Then a machinist buddy of mine tried them and told me to scrap them. Onto the project!


Here I start with a 3" piece of CRS. Just some stock I have around. I wanted a solid, one piece cutter, instead of a screw on shank. 


I figured a 1.5" shank would suffice, minus a little for a taper into the main head


After quite a few passes (and a couple beers later) the shank is turned down to 27/32", my second largest R8 collet. 
	

		
			
		

		
	



Reversed in to chuck and faced and cleaned up. Notice the change to the 4-jaw chuck, for accuracy. That's all for tonight, I'll post more as I go


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## Mark_f (Mar 24, 2015)

Are you making a different design? If not why would the new one be better than the old one.

I bought a cheap import set and the were just like everything else from over there, A kit to be finished. I cleaned the cheap ones up in my lathe , drilled out the set screws for a larger American thread ( the tiny screws they used let the tool slip). and ground some HHS tools and they work great now.


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## Maddogmech1 (Mar 24, 2015)

Yes, I'm going to use a slide bar, with carbide inserts, the bar will slide parallel to the work, and lock down with set screws


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## Mark_f (Mar 24, 2015)

Oh...ok. I have seen this type. I look forward to the rest of your project and how it works for you.


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## Maddogmech1 (Mar 26, 2015)

Didn't have much time in the shop tonight, but got a little done. Thought I'd start on the cutter bar so I had measurements to go off when finishing the head


	

		
			
		

		
	
started with a piece of 5/8" plate and cut to size, then squared up in the mill. I figured the main part would be 1", while the end with the cutter .01 thicker


	

		
			
		

		
	
mocked up the insert and drill/tap for M5x.08 cap screw. I got a bunch of these inserts from eBay on the cheap. 


	

		
			
		

		
	
roughed out shape of the cutter bar. 


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## Maddogmech1 (Mar 28, 2015)

I love Saturdays. I decided first thing today I'd work on the finish of the head, as I didn't want to have to fight the slot and setscrew holes. 
	

		
			
		

		
	



	

		
			
		

		
	
here it is after some finesse with sandpaper in the lathe. I went down to 800 grit for a nice satin finish. 
	

		
			
		

		
	



	

		
			
		

		
	
found center for the side of the cutter bar slot
	

		
			
		

		
	



	

		
			
		

		
	
milled slot out. I know, I know, where's my V-block? I don't have one yet, so I took light .020 passes all the way to 1" depth. 
	

		
			
		

		
	



	

		
			
		

		
	
slot milled
	

		
			
		

		
	



	

		
			
		

		
	
i used a 1/2 endmill and located and milled flats where the setscrews go. Then drill/tap to 3/8-16 for the screws. 
	

		
			
		

		
	



	

		
			
		

		
	
here she is all pretty. Does it work?
	

		
			
		

		
	



	

		
			
		

		
	
I'll let the pics tell the story. That's a .005 finish pass at 800 rpm in alum


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## Maddogmech1 (Mar 28, 2015)

heres a piece of junk hot roll I had laying around. This stuff is a bear to machine so I'm pretty happy with the finish. 


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## Mark_f (Mar 28, 2015)

Very nice.


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## Doubleeboy (Mar 28, 2015)

Nice work.  I have found the key to a good finish on Hot Roll is light finish cut, at gold or blue chip speed with fresh insert and tram the head slightly out so the trailing edge does not cut, or worse drag a chip around scratching the surface.   I have gotten finishes that look like a mirror.  One chip dragging can ruin the whole thing, as can a built up edge on cutter.

michael


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## oldboy1950 (Mar 28, 2015)

nice work on that cutter!
by the way how is the cutter shank held in the spindle ?
Dan


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## thomas s (Mar 28, 2015)

Nice job on the cutter and good pictures.


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## Maddogmech1 (Mar 28, 2015)

Thanks for the feedback, I do like to get people's take on things, I've learned a lot that way. 
Oldboy the cutter shank is held in with an R8 collet, this one happens to be 27/32, but you could make it whatever. I'm happy enough with this cutter that I think I'll end up making a smaller one of the same design for narrower material. 
Doubleeboy I'm curious as to what you mean blue or gold chip speed, is this faster feed, or higher rpm? Or both? I'm still trying to learn the ropes of feed/speed so any info on it to get a better finish will highly valued. Especially for hot roll, simply because I have an almost unlimited free supply of it so I tend to use it frequently. 


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