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Boring/Facing or dedicated fly cutter?

BHolcombe

Aluminum
Joined
Apr 15, 2019
Is a boring/facing setup like that produced by Gamet/Enco capable of providing a perfectly clean surface finish so much that something dedicated to fly cutting like those produced by suburban tool would be an unnecessary addition?

I don't intend to do much fly cutting, but it would be nice to have the additional capability. I also don't do much boring but would like to add the capability. Would be nice to use one tool for both and actually see some routine use out of it combining the two features, but I'm curious if this is advisable or if a boring/facing tool makes a lousy fly cutter.

Thank you.
 
If you don't care about holding bore tolerances,sure go ahead and use your boring head as a fly cutter.
There's a reason they are 2 different tools.
 
Hey, there's a whole new technique I'd never considered. So I've got this 6" x 8" cast iron plate I need to surface. Ditch that cranking all the X and Y handles and making multiple passes. Now I'm looking for an automatic facing head, heavy duty so I can take a decent cut, and I'll start in the middle and let it face the whole thing on automatic.

Of course I'm being facetious and teasing the OP a little about knowledge and experience though we all started in the same place knowing nothing about anything. Mtndew is pointing the right way. Multi-tooth cutters are great for efficient material removal. Fly cutters are slower but offer a wider sweep and usually a good surface finish. (Cutter geometry important here) Boring heads are great for straight holes and can produce very accurate sizes depending on features, tool condition, and operator experience. There are a few instances where a smooth square face to a hole is important and the facing feature comes into play.

Choose from an array of tools to suit the job at hand though I expect every machinist with years behind him will have stories about accomplishing a task without the right tool through ingenuity, courage and holding his mouth right.
 
Hey, there's a whole new technique I'd never considered. So I've got this 6" x 8" cast iron plate I need to surface. Ditch that cranking all the X and Y handles and making multiple passes. Now I'm looking for an automatic facing head, heavy duty so I can take a decent cut, and I'll start in the middle and let it face the whole thing on automatic.

Of course I'm being facetious and teasing the OP a little about knowledge and experience though we all started in the same place knowing nothing about anything. Mtndew is pointing the right way. Multi-tooth cutters are great for efficient material removal. Fly cutters are slower but offer a wider sweep and usually a good surface finish. (Cutter geometry important here) Boring heads are great for straight holes and can produce very accurate sizes depending on features, tool condition, and operator experience. There are a few instances where a smooth square face to a hole is important and the facing feature comes into play.

Choose from an array of tools to suit the job at hand though I expect every machinist with years behind him will have stories about accomplishing a task without the right tool through ingenuity, courage and holding his mouth right.

Thank you for clearing up my confusion. I assumed facing was the same as face milling, but that makes much more sense that one would face a bored hole after making it.

As mentioned, I did not do much boring since there is little call for it in the parts that I make. So forgive my ignorance please.
 
usually boring head is just a more easily fine adjustable flycutter. most but not all boring heads take inserts which normally are made for boring or facing often they dont have cutting edges for both
.
finish is usually ok with care but if spindle out of tram you will get a concave or not flat surface with larger diameters
.
usually not a good ideal to do roughing with a flycutter slow rpm and trying to take alot the cutting forces or wack wack wack can be severe enough to do machine damage and move parts in vise or fixture
 
usually boring head is just a more easily fine adjustable flycutter. most but not all boring heads take inserts which normally are made for boring or facing often they dont have cutting edges for both
.
finish is usually ok with care but if spindle out of tram you will get a concave or not flat surface with larger diameters
.
usually not a good ideal to do roughing with a flycutter slow rpm and trying to take alot the cutting forces or wack wack wack can be severe enough to do machine damage and move parts in vise or fixture

Thank you, appreciate the reply. I intend to use it only for light cuts. I dislike the appearance of multiple passes on a finished surface so often enough I'll take a finished part and have it ground or hand lap it. Only issue is that not every part really calls for that level of work.
 
IMO, once you use a face mill with the right inserts and the mill trammed correctly, you'll never consider anything else. Boring heads are for boring.

I have plenty of them, I just only have them up to a 3.5" diameter.

I tram the mill and tip the spindle about .0005" over a few inches (typical sweep), enough that the cutter doesn't cut on the back side but not so much that I'm making a big hollow.

I've done plenty of face milling, but just nothing with a fly cutter. Frankly, I've always bit a tad nervous about fly cutters and I do appreciate that they're hard on the bearings. I've decided to pursue this because I would like to be able to finish surfaces with a higher quality result without resorting to grinding/etc.
 
As said above, a boring facing head is a high precision piece of equpiment. It's intended to be used to bore a hole and then face off the top and/or bottom of the hole nice and flat. I use a big Chandler often in a #3 Cincinnati vertical for putting bushings in parts that are hard to hold in the lathe. You can bore out the damaged fit and face off the bottom square. Make your bushing in the lathe and leave it about .050 small on the bore. Loctite the bushing in, bore to size and then face off the length flush. Then engage the auto face with the mill head feeding upwards to chamfer the corner.

Using one for a flycutter, even on light work would be the equivalent of using your dial indicator as a hammer.
 
You don't have to pay the high price for a flycutter from Suburban Tool to havve a decent flycutter. That's a Cadillac. They're very easy to make, but you can buy them almost as cheap as you can make them.
 








 
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