# Home made Fly Cutter



## basildoug10 (Feb 16, 2015)

Hi, on a previous, and my first ever post, on the "Beginners" forum was a few days ago. I did however get some very good advice. The outcome of that was as follows. I would purchase an index able type face cutter to replace my existing face cutter as it was not an easy tool, to sharpen 3 separate tool bits in an identical way so that all 3 bits picked up an equal share of the cutting. But at the moment spare cash for a new cutter is not available at present. So having read other posts regarding tooling that has been home made and, the pictures are amazing, the quality of the tooling is also outstanding!

Below is my present face cutter that uses 3 HSS bits.




So I thought I should give it a go and make a Fly cutter, and perhaps making some simple tooling is a start in the same direction like so many others that  have been so successful in making great tooling.

So I started as follows, I mounted my huge milling vice on my trusty "Chinese 3 in 1" machine and squared off the jaws.




This is the blank that I machined earlier.




Clamped the blank in the vice and set the angle at 16 degrees,  I thought this would be a reasonable angle.





Started milling with a 10mm Slot drill at 836 rpm, (is this the correct cutting tool to use?)





Stopped for a picture, almost done




Done with milling the 16 deg. face angle




Busy with the 6mm  tool bit slot




Milling completed. Please comment on the surface quality of the slot. Seems a little bit "Rippled"
Perhaps I am using the wrong cutting tool?





Fly cutter clamped for drilling and tapping of holes for the Pinch screws




All done, and now for the TEST. I have a piece of scrap 25mm thick mild steel off cut which I use as a small hand hammer to rap on what ever needs a little "knock". So I used this for the test. Spindle speed is 290 rpm.





Well it seems to work much better than my "3 HSS BIT" face cutter.




Here is the tool, it is 24mm dia. and it has a 13mm shank, and with the tool bit set where it is, it cuts a 34mm wide swarth. Since taking this picture I have replaced the small pinch hex screws with "cap head" screws.




I did make a mistake in the machining of this fly cutter, and I am sure that nothing gets passed you guys, so I will just come clean and tell you. I am sure you spotted the mistake. I milled the slot for the tool bit on the wrong side of the center line, so this fly cutter has to run anti clockwise to cut.
Well these type of mistakes will go as experience increases.
I would certainly appreciate your comments, as I can only improve from them


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## Andre (Feb 16, 2015)

Nice writeup, I like your facemill. Did you make it? 

When you were indicating your vise, it looked like you were indicating off the moving jaw by the picture. Make sure to indicate the fixed jaw not the moving one, as it does not have the slight bit of wiggle the moving jaw


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## basildoug10 (Feb 16, 2015)

Hi Andre, I assume the face mill you are referring to, is the first picture of that MT3 cluster thing with 3 x HSS tool bits, No I never made that, it came with the HQ400 Chinese 3 in 1 Lathe mill/ machine that I purchased 14 years ago.
Good spotting on the issue of indicating on the moving jaw. To be honest, I never gave it a thought. You are quite correct, thanks for pointing that out.
Regards Basil


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## Inflight (Feb 16, 2015)

Nice write-up!

That is a nice looking cutter but I think  you can improve the surface finish and reduce tool pressure if you knock the sharp corner off the bit so it is presented to the work at 30* or 45*. You won't be able to machine up to a sharp corner, but that is somewhat rare with fly cutting tasks.


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## Andre (Feb 17, 2015)

Inflight said:


> Nice write-up!
> 
> That is a nice looking cutter but I think  you can improve the surface finish and reduce tool pressure if you knock the sharp corner off the bit so it is presented to the work at 30* or 45*. You won't be able to machine up to a sharp corner, but that is somewhat rare with fly cutting tasks.



Yes, either grind an angle on the leading edge of the tool or a 1/32" radius or so. Good point!


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## T Bredehoft (Feb 17, 2015)

You might want to replace your cap screws with set or grub screws, will reduce some of the balance problems, also will hold the bits better.


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## eightball (Feb 17, 2015)

You could also  use your facemill with only one toolbit in it. You could put the other two bits, where they wouldn't cut if balance is an issue.


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## Andre (Feb 17, 2015)

T Bredehoft said:


> You might want to replace your cap screws with set or grub screws, will reduce some of the balance problems, also will hold the bits better.


Besides possibly a better grip on the head, why would a cap screw hold better?


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## basildoug10 (Feb 17, 2015)

Inflight said:


> Nice write-up!
> 
> That is a nice looking cutter but I think  you can improve the surface finish and reduce tool pressure if you knock the sharp corner off the bit so it is presented to the work at 30* or 45*. You won't be able to machine up to a sharp corner, but that is somewhat rare with fly cutting tasks.



OK that is a good point, in the past 14 years of owning my beloved "Chinese 3 in 1 machine" , the only work that I have done is to make Bushes and washers and the occasional odd bits and bobs. Since joining this Hobby and machinist forum I have become a "machine freak"  you guys are so experienced and your help and assistance is exceptionaly good.
So your point regarding the angle that I should sharpen the tool at, is a good point. I did notice that  the finnish was a little rough. Incidentally, the tool bit that I used in the fly cutter was made by a friend many years back and the only reason I used it, was because it was the only 6mm tool bit that I had. I actually had no clue whatsoever  how to sharpen a fly cutter bit till reading your comment now. So I am grateful for your input.


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## basildoug10 (Feb 17, 2015)

T Bredehoft said:


> You might want to replace your cap screws with set or grub screws, will reduce some of the balance problems, also will hold the bits better.



I bought cap head screws yesterday to replace the hex head screws that used. My first choice was to fit Grub screws
but the local hardware store ( a round trip of 160 Kim) did not keep them so I settled for the Cap head screws.
I agree the grub screws would look a lot neater. Thanks for your input


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## T Bredehoft (Feb 17, 2015)

_Besides possibly a better grip on the head, why would a cap screw hold better?_

In the US of A, grub screws (locally called "set screws") are hardened, as opposed to being just grade 8 or what ever. Vibration of the tool won't distort (blunt) the head of the screw as much.


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## basildoug10 (Feb 17, 2015)

eightball said:


> You could also  use your facemill with only one toolbit in it. You could put the other two bits, where they wouldn't cut if balance is an issue.



Hi, I also thought of perhaps using my original facemill with just the one tool bit and leave the other two bits out. But I did not have the courage to try it. If I could use the tool with one toolbit instead of all 3, I will be very pleased. So I am definitely  going to try it with one bit. Thank you for the help.


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## Mark_f (Feb 17, 2015)

I am impressed with your little flycutter. I think it came out nice even with your mistake in the slot, which doesn't really matter as long as you run it the other direction. Just tell everyone it is a left handed cutter. Someone once asked me why all my mill arbors have left hand threads on the ends. I told them because I am left handed and stand on the other end of the machine. While that was partially true, the real reason was , It was easier to single point the threads making them because the tool ran left to right on the lathe and I wasn't threading to a shoulder. (god I miss the smileys here).


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## 18w (Feb 17, 2015)

Basildoug, your flycutter turned out well and your next one will be better because of the experience making this one. If you look on youtube for Toms Techniques he has an excellent tutorial on flycutting. He also has a great drawing of a properly sharpened bit for a fly cutter on his website also called Toms Techniques. I would give you a link but unfortunately I can sharpen tools better than I can operate a damn computer.

Regards
Darrell


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## basildoug10 (Feb 18, 2015)

mark_f said:


> I am impressed with your little flycutter. I think it came out nice even with your mistake in the slot, which doesn't really matter as long as you run it the other direction. Just tell everyone it is a left handed cutter. Someone once asked me why all my mill arbors have left hand threads on the ends. I told them because I am left handed and stand on the other end of the machine. While that was partially true, the real reason was , It was easier to single point the threads making them because the tool ran left to right on the lathe and I wasn't threading to a shoulder. (god I miss the smileys here).






mark_f said:


> I am impressed with your little flycutter. I think it came out nice even with your mistake in the slot, which doesn't really matter as long as you run it the other direction. Just tell everyone it is a left handed cutter. Someone once asked me why all my mill arbors have left hand threads on the ends. I told them because I am left handed and stand on the other end of the machine. While that was partially true, the real reason was , It was easier to single point the threads making them because the tool ran left to right on the lathe and I wasn't threading to a shoulder. (god I miss the smileys here).



Hi Mark, thanks for the comments about my fly cutter, ( the first real tool that I have ever made)  well it is definitely not in the same league as your tooling that I have seen on this forum, but your collection of tools which you have made is what got me going, to start making some of my own.
Your comment about the "left handed incident" hilarious, 
Regards Basil


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## basildoug10 (Feb 18, 2015)

18w said:


> Basildoug, your flycutter turned out well and your next one will be better because of the experience making this one. If you look on youtube for Toms Techniques he has an excellent tutorial on flycutting. He also has a great drawing of a properly sharpened bit for a fly cutter on his website also called Toms Techniques. I would give you a link but unfortunately I can sharpen tools better than I can operate a damn computer.
> 
> Regards
> Darrell


Hi Darrel, thank you for the info, I will certainly take a look. I re-sharpend the toolbit for the fly cutter today in an attempt to improve the cutting, although the surface looked smoother, it is still far off from what I seen. I really need to learn how to sharpen tool bits for the fly cutter.
Regards Basil.


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## Mark_f (Feb 18, 2015)

basildoug10 said:


> Hi Mark, thanks for the comments about my fly cutter, ( the first real tool that I have ever made)  well it is definitely not in the same league as your tooling that I have seen on this forum, but your collection of tools which you have made is what got me going, to start making some of my own.
> Your comment about the "left handed incident" hilarious,
> Regards Basil


Thanks. If I gave you any inspiration, I did my job. 





basildoug10 said:


> Hi Mark, thanks for the comments about my fly cutter, ( the first real tool that I have ever made)  well it is definitely not in the same league as your tooling that I have seen on this forum, but your collection of tools which you have made is what got me going, to start making some of my own.
> Your comment about the "left handed incident" hilarious,
> Regards Basil


Thanks. If I inspired you in any way, I did my job in life.


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## magu (Mar 3, 2015)

Basil, I just made my own fly cutter after reading though your thread so thank you for the inspiration! As for the surface finish in the slot, I has the same "rippled" finish. I made my 3/8" slot with a 3/8" end mill and found that by bumping it over just a hair (so I was only cutting one wall) I got a much better surface finish. Next time I think I would use a slightly smaller cutter and finish up to the tool width so I could get a good surface _and_ a nice sliding fit.


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## darkzero (Mar 3, 2015)

> T Bredehoft said:
> 
> 
> > You might want to replace your cap screws with set or grub screws, will reduce some of the balance problems, also will hold the bits better.
> ...



Also, set screws normally come as cup points (here in the US anyway). Cup points typically dig into the part being held (depending on hardness of course) so they grip better. You can specify which point type you want when buying from a supplier like Mcmaster but if you buy set screws from a hardware store or something, cup points are pretty much the standard for set screws.


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## Andre (Mar 3, 2015)

darkzero said:


> Also, set screws normally come as cup points (here in the US anyway). Cup points typically dig into the part being held (depending on hardness of course) so they grip better. You can specify which point type you want when buying from a supplier like Mcmaster but if you buy set screws from a hardware store or something, cup points are pretty much the standard for set screws.


Very true, on cheap HSS you can actually see where the cup has dug in. If possible, get ones with a serrated cup. They grip like a monster!


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## darkzero (Mar 4, 2015)

Nah, I use flat points in all my tool holders.


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## basildoug10 (Mar 25, 2015)

magu said:


> Basil, I just made my own fly cutter after reading though your thread so thank you for the inspiration! As for the surface finish in the slot, I has the same "rippled" finish. I made my 3/8" slot with a 3/8" end mill and found that by bumping it over just a hair (so I was only cutting one wall) I got a much better surface finish. Next time I think I would use a slightly smaller cutter and finish up to the tool width so I could get a good surface _and_ a nice sliding fit.


Hi Magu , I just saw your comment on preventing the rippled effect on the slot sides. I like your Good idea to use a slightly smaller cutter  and to cut each side independently till the slot width is at the correct size to get a nice finnish. Also I see you milled a small chamfer at the end of the slot where the tool bit protrudes, that is a nice touch. Thank you for your comments.
Basil


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## Mach89 (Jan 19, 2017)

> I milled the slot for the tool bit on the wrong side of the center line, so this fly cutter has to run anti clockwise to cut.
> Well these type of mistakes will go as experience increases.
> I would certainly appreciate your comments, as I can only improve from them



Don't feel bad. I have an indexable endmill I made at work that I have to run in reverse. But that was because my design didn't account for the slant in the insert going the way it did. But, that's why we have reverse. Your fly cutter looks good by the way. I recently made one myself for my shop since I couldn't find the one I made in college.


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