Shop Talk 17 Flycutters & Tool Bits 

steel on aluminum is NEVER good, carbide always gives better results...

big tool stickout + interrupted cut make for a bad mix. here's what you do: - grind 10* top rake - grind 15* side clearance - grind large nose radius - polish all cutting edges - put the HSS away - use your surface grinder! ;)

My all time favorite Abom comment, "smok'em if ya gott'em"... I've said that myself many times. Just made me smile. Thanks for that.

Nice project, good lesson on grinding HSS cutter. Grinding tool bits is a science that not many guys get into, there's lots to be learned and I'm glad you're passing along 3 generations of knowledge. Thanks

That tri-stone tool is one of the coolest things I’ve ever seen. I appreciate older tools that have been used and kept up. Thanks for showing it

I bet those great memories come out a lot whenever you use your Dad's and Granddad's tools. -Ric

Most of what you do and explain to us is wayyyyyyyyyy beyond my pay grade. But I do pick up how I should approach projects. Your down to earth way of explaining machine work brings all of us along to a understanding of what is required to to a job the right way,. Thank You !

I like the way Adam keeps it real and I like the way that This Old Tony responds. Good interaction guys! Thanks for your effort with these vids. Best. ~gjl.

A few suggestions. I have worked in the mold industry for over 45 years specializing in aluminum molds. For the first 20 years it was manual machines only, CNC's were not available to us until late 80"s. First, we never used coolant of any kind when fly cutting. Sure we tried it, even WD40, but we found cutting dry made no difference in finish and besides, no one wanted to stand next to the machine and be sprayed with oil. Even today we don't use anything when we are using a face mill on the CNC. Second, when manual fly cutting large surfaces rigidity is a must so the cutter holder should be larger than the area it's cutting whenever possible. A 3" fly cutter with the bit sticking out 1.5" just won't work very well on a 6" piece. We made special fly cutters up to 12" diameter using a round aluminum plate with a steel center hub and a slot cut into it on an angle for the tool bit. The tool bit would only protrude as little as possible. The tool bits were off the shelf brazed on carbide tipped. HSS would never hold up for more than a couple of passes. The carbide ones lasted for months of daily use. Finish was determined by the feed rate. A tip for doing large plates: double tape them down to a rotary table and rotate it leaving the machine table stationary. You'd be surprised how flat and parallel you can make it provided the head was trammed in good.

I do love hearing the stories Adam, great family history, glad you shared that

Adam, thanks for all your videos. I think they are great. I am not a machinist, but think I want to pick this up as a hobby. Guys like you, Tom, The Keith's, Randy, Joe, Stan and countless others have inspired me. I am pretty well confined to a wheelchair or sitting in a chair or stool, but I would love to putter around in a shop making... well... stuff. You guys have really been an inspiration to me. I have watched literally THOUSANDS of hours of videos and I am hungry for more all the time. Also, it's not just me. Thank you for all you do and give to the community.

Remember Mrpete222 alway says: there a thousand ways o do things, as long as you get the results you want. And it gets the Job Done.

Thank you for the comprehensive info about fly cutters, I feel I have a better understanding of the geometry and grinding/sharpening. I have avoided using the fly cutter on my small (hobby) mill but I now feel better ready to use it... firstly I am adding a more massive base and bench mounting to reduce vibration. Thanks again, I also enjoy using my Father's and a few of my Grandfathers tools. Glad you are keeping the family in sight.

thanks again Adam. always fun watching you.

Another great video. I LOVE your attitude and kindness towards all. You're awesome!

first time I seen this mans video and hands on tool making I have picked up some great tips a credit to RU-vid I have subbed and hope to learn more from this man no matter how good or big you are you will always learn something from another man

Thanks for their quick on flycutters. Enjoyed the vid left smiling Will

Ian from Oz Adam--good demo and a good subject to illustrate--you will always get a thumbs up from me..

That is one tool and operation I have yet to do here, so I appreciate your sharing. Thanks Adam... Razor!

Watching @11:30-12:00 I kinda had the feeling of watching a master work at his craft. Kind of like getting goose bumps when listening to your favorite singer sing a part of a song if that's a better analogy. I grind 75% of the tools I use and I know it takes some practice and skill to get it perfect, as you say "home shop" there is never any rush. I just want to say that I really truly appreciate all the detail you go into when doing a lot of the "setup" steps, it's like welding, if the prep work is sub par, the end result will be sub par.

Glad to see they honed their knives on the same stone. Family history and continuity is important.

Thanks Adam, I now understand a bit more on Fly cutters. I really appreciate your videos. I'm not a machinist I and a designer of Machinery. Thanks again and please keep up the great work

Great. Haven't seen a hand dressed tool for how long. Good story about the old boys and cleaning fish. You've had a good upbringing

smoke em if ya got em. someones been watching that canidistanian chappy. you boys rock. Thanks adam. Nice to see you so relaxed and enjoying makin vidjeos for us.

In case anybody is wondering what kind of sharpener that is, it is a IM313 Norton 3 way multi oilstone system. They still make them today.

I wish I had some of my grand dad's and dad's stuff. Thanks for the demo. Greg

Great advice on the HSS tool honing and thanks for the fly cutter demos. One of these days you will have to put leveling pads on your mill and a lot of the vibration/chatter in your finishes will be eliminated. Thanks, again.

Great video. Thank you for sharing the difference in the tools. Looks awesome.

i really like that hone, three different grades in its own little oil bath..... first time i've ever seen one

It's a flex issue I suspect......not a balance issue.......I was waiting for this vid! Loved it.

Nice video Adam. I wish some of the people who comment on here would use their brain before they speak. There is a right and wrong way to do anything, but sometimes you do what works the best with what you have available. Not all of us have all the proper fancy tooling for every job under the sun, that stuff is really expensive.

i remember making a flycutter as a project in high school. memories

nice video Adam! thanks for sharing

Abom, Another good video. Thanks for the knowledge. I like the flag on the wall, you have my respect sir!

Happy memories; cleaning fish and telling tales with the Booth men.

Fly cutters are sharp and good for machining silicon bronze repair work.

17:33 - I can see that pattern is caused by the frequency that the tool is resonating at. It's acting as a tuning fork as it "squeaks" and this causes it to vibrate the pattern into the aluminium, just as a vinyl cutter cuts sound into vinyl records. Perhaps you could wrap rubber bands or something around the cutting tool to dampen the resonance so it doesn't act like a tuning fork. That should make the pattern less visible. EDIT: The best way I can explain it is when technicians skim brake discs. They put a large rubber band around the brake disc to stop it from "ringing". Prevents the awful squeaking sound and probably helps to reduce high frequency chatter too. :)

Very helpful information, Adam Thanks for sharing

Nice job Adam, considering the interrupted cut I think you got a good finish on the plate. I too have had good luck with HSS and aluminum. Those brazed carbide bits are good for fly cutters too, they hold up a little better and are pretty cheap. That was a good story about the Booth men cleaning fish, funny how those simple things stick in your head.

Adam, The tri-stone is one very neat item. Thanks for showing how important it is to hone the edge of the tool. Eric

I like those stones like you said they been around awhile.

My solution for large area surfacing (cylinder heads in particular) was a large thick disc fitted to my shell mill arbor. Different size toolbit slots cut in the periphery with setscrews. I think I may have shown it in my own pallet build vid some time back. Little to no chatter as the toolbit has minimal stickout. :-)

Hello Adam, Thanks for another informative video. It is beneficial to me more than would be apparent to watch these videos (and they are fun) as when I go in my shop the behavior of the tools and setups is ingrained much more than my limited experience would warrant. So I can catch a bad feed or a poor setup (well sometimes!) that would have gotten by me otherwise. It has certain similarities to muscle memories and I get them right here in my easy chair! Added to that you have an easy flow to your presentation. Enhanced by the fact you don't use the royal "we" (Just kidding Keith!). Very enjoyable and worthwhile. Keep them coming. Of course you have me spoiled now and being mid week I was expecting a travel episode with a restaraunt!! LOL! Take care. Doug

As always Adam great video. I think if the DIA of the fly cutter was larger so that there was less tool hanging out it might not chatter, or a thicker tool.

We had that same hone box on our submarine to keep the cooks knifes sharp....Jack

I'm getting better on my HSS grinding . Enjoyed Adam .. Thumbs up !!

It sounds like there is a knock in your spindle, it may be the source of your vibration? Particularly evident at 19:00

Hey Adam, I have always had a hard time getting the mirror finish using fly cutters and have tried several different tool grinds using quality HSS but never as nice as the carbide face mill gives. Great video, thanks man!

I remember that same sharpener at the small meat market I worked at as a kid. It was used every day back before they had a grinding service for the knives.

Adam thanks for taking your time and sharing. I get that there are other methods of making a plate flat but that wasn't the point of your video. You said that in the beginning. Several commenters mentioned counterbalancing the tool holder. It won't prevent chatter/resonance but will eliminate the balance problem allowing you to go much faster. joshua43214 may have something there with the 0* rake angle and the interrupted cuts. Jim Griffiths noticed that the tool is howling at a high frequency. That was what I noticed as well. The tuning fork idea will certainly cause the tip of the tool to not be steady and it would show up as a chatter pattern. You need damping in the tool holder. I was thinking of clamping a piece of wood to the cutting tool to dampen out the resonance. Something as simple as radiator hose clamps holding the wood against the tool. My takeaway is that chatter is a resonance phenomenon and adding a dampening material is the cure. As always, thanks again for sharing.

jealous of your honing stone set!!

That sharpening stone is very cool.

Thanks for the video Adam.

Hey Adam, You got that cutting edge honed good and sharp! One suggestion. Aluminum will stick to the top surface (as mounted in a lathe). You should polish that surface as good as you can before dressing the cutting edge to make the aluminum slide off. Also, for the best finish, there should be a slight flat in the radius to match the feed rate you expect to use. Same principle as putting one wiper chip in a face mill. Be careful though, too much flat will cause chatter. You have enough of that already..... Ever consider milling some material off the thick side of that big fly cutter to balance it better?

While the answer to my questiion will be painfully obviious to most, Where is the RADIUS in relationship to the cutting edge/pint?? On the leading edge or trailing edge. (If you would paint the tooling blank with any color on the TOP of the tool, I could follow your turning and twisting while you grind and hone it!) Great source for information/learning Keep up the good work!!

Smoke 'em if ya got' em! You also mentioned your Starrett 60" vernier caliper "having a lot of gravity." AvE references? Love your channel, Adam. I've only been following and binge watching your videos for a couple of months, but I'm hooked.

Great fly cutter vid, thanks!

i got my, like brand new, copy of, audels machinists and tool makers handbook in the mail yesterday. it literally is like a bible. it even looks like it goes with my bible. i'm glad you talked about it in that video of yours i saw. it's a fantastic book.

This is cool! I was wondering what a fly cutter was used for. Thanks man. Great video.

So where is it written (other than say, fly cutting a large convex/concave radius with head angled) that it all needs to happen in one pass? Why not pull the the tool in to a reasonable (more rigid) diameter and make 2-3 passes (y axis)? You'll get some overlapping marks but they won't mean anything. And it seems like once you get chatter on a surface, it's harder to get rid of it (with light cuts anyway) - the "chattered" surface seems to help create more chatter. You're the best - keep up the good work!

I work typically on small parts, so I can surface in a single pass with a 2" indexable with carbide inserts and I get good results that way, but I rarely machine aluminum, mostly cast iron, brass, bronze.

And simple gets the job done. Flycutters are great if the job demands it...

I used a boring bar in a boring head, and turned it upside down and got excellent results on arcylic, but I haven't tried aluminum yet.

I was thinking I'd be really funny and send you the 'tiny' 1" fly cutter I made, but you already have a collection...

If we need super flat and shiny aluminum parts we surface grind them after fly cutting. Use way oil when grinding and you'll almost have a mirror finish.

Hi Adam. May be it would be possible to balance the holder± because of its angle shape means that the center of the fly cutter needs to be brought back right into the center of the mill. It might be possible and interesting experiment to try to balance it by adding a counterweight so that it is perfectly which makes the cutter stable to allow it to be used at a much higher spindle speed

i loved it when you said "and let'er rip". somehow that was so funny. :D

Adam, I wonder if it would help with the vibration to insert a business card in between the tool holder (or cutter) and the fly cutter fixture? Eric

I used those exact stones 25 years ago when I was a meat cutter at Publix.

In my humble opinion flycutting can be one of the most dangerous machining operations. One particular danger is having the toolbit protruding outside from the cutter body. The toolbit can become almost invisible when spinning, giving the impression that the edge of the cutting is performed at the cutter body edge. This extended condition also creates an out of balance tool. The leverage on the toolbit is greatly increased as its clamping zone is further from the cutting edge, reducing its security in the holder. Rigidity is key when using a flycutter & a short projection will help this & reduce the "invisible" danger area surrounding the body. A cutter body larger than the width of the part is preferable allowing the toolbit to be inside the body, removing the invisible danger area. In an ideal situation the fly cutter would only be slightly larger than the width of cut. When a relatively large swing on a cutter is used compared to the width of cut, the tooth engagement angle becomes almost 90 degrees to the part. This gives a sudden impact when the full tooth load is immediately applied on contact. This full feed of cut is maintained throughout the shallow cutting arc maintaining full load throughout. Giving a constant chip section with the force maintained at right angles to the part width. The resulting clattering of the tooth impact can lead to chatter & tool chipping. An excessive toolbit overhang also can lead to back cutting due to the increased leverage that can deflect to toolbit upwards during the cutting phase of the stroke. The back cutting is caused by the tool springing back to its unloaded condition. This is eliminated on a shaper by the clapper box allowing the tool to lift on its backstroke but not available when flycutting. Using a smaller swing, the tooth engagement angle becomes more tangential to the part. This has the effect of an initial light load on the tooth that smoothly & gradually increases then decreases to almost zero on exit. This greatly helps with chipping on the back edge. This light initial load is resisted by the rigid length of the part & therefore far more stable. This chip section is a crescent shape with a tapered feed to the full chip width & immediately tapering back to zero. This crescent shape directly represents the tool load & direction spread throughout the arc. The highest load on the tool only happens briefly half way through the arc instead of throughout the whole arc. This greatly reduces the chances of premature chipping & chatter marks, it's also a lot quieter! Another bonus is that as the tool is effectively a smaller diameter, a higher rpm can be used. The stability obtained with the load being along the length at engagement, can allow a deeper cut. If the feed per tooth remains constant then the feed can also be increased. If you don't have access to a small enough tool there is a solution to help with the issues outlined. Move the workpiece towards you until the cutter tip just passes over the front edge of the part. This will also give a tangential engagement, thereby reducing tool impact, reducing vibration & chatter, especially on thin parts. Hope you find this info useful.

hey Adam if it is a balance issue causing the vibration at the higher speeds why can't you counter balance by letting the same amount stick out on the opposite side of the cutter insert.. granted I am not a machinist so just asking

THANK YOU LIKE THE FISH IDEA GOOD OLD OLD SCHOOL SURVIVAL

Your chatter with the HSS is coming from two sources, the nose radius is too large, and there is too much rake for the size of the cutter. The tool is actually getting pulled down into the work by the rake. Not such a problem on flat stock, but with all the holes, the tool ends up flexing up and down. Going with a smaller radius will reduce the force acting on the tool, going with 0 rake will prevent it from diving into the material, and adding some negative lead angle will held even more. Make the tool look like a left hand cornering tool with 0 rake and it will leave your best finish.

Hey Adam, I had a chuckle when you referred to the Bridgeport as a little mill (4:00)... I know that when compared to my RF45 clone your Bridgeport would certainly be considered a BIG mill.

i use canola cooking spray on aluminum and it works great

I'm no machinist but I enjoy the videos. If the flycutter being off balance is an issue, why isn't there a counter weight?

Is that a Dexter Tri Stone. I've seen them since I was a kid and always wanted one. They're still available for around $200. Have you had to replace any of the stones?

If you drill some calculated depth holes in the front part of your fly cutter you can get it balanced better and run at higher rpm’s

21:46 is an "Abom Size" quicky...LOL! Thanks Adam, I love to sit and sharpen things, and while I know it doesn't make for great video, I'm going to bring my stones and tool-bits into the house and go at it while watching videos. One question, do you hone the other edges smooth, or leave them ground finished? Thank you.

hell looks good from here.

Hello Adam, just finished my first "mill' project. A fly cutter. Do you have any advice on fly cutting "rusted" mild steel?

Hey Adam, I'm building myself a flycutter and I tried to look up that kennametal tool for the carbide insert and I can't find anything online. Any idea where I can find one?

Interesting video but cuts a little deep. 002 gives less chatter and a better finish. In perfect tram you'll always get some back drag. The leading edge lifts slightly while cutting followed by a lighter cut by the trailing edge.

i dont watch abomb to comment on what he is doing wrong i want to know outher ways to destroy problems we all dont have every tool or setup there are more than one way to skin a cat and i appreciate the time he puts into his craft

It's a lot prettier than what my machines do.

I had some 303SS parts that needed to be fly cut a while back. I had a brazed carbide tool in the cutter. The corner got beat up pretty quick. So I ground up a HSS blank, and it held up better than the brazed carbide. I guess the carbide couldn't handle the interrupted cut. Just goes to show carbide is NOT always better than good old HSS.

adam interesting video thank you.

Adam- do you have any comment on fly cutters vs your shaper? Seems to me both are tools designed for cutting a flat surface. I suppose that in *this* situation, the fly cutter was appropriate as you were essentially squaring the pallet plate to the mill spindle, but as far as other operations where you're simply looking for a flat surface- would you be more inclined to fly cut, or use the shaper?

great video i love that tri stone

Hello Can you say me please which angle had your fly cutter? Best regards sina

Looking forward to the DoAll Leveling Video.

looks great man

Call me crazy, but wont cutting a flute in the top and bottom side of the cutter give it some rigidity? We use it to stiffen blades and barrels.

I need to make a large flycutter. I'm not a fan of hanging the tool out. That said, other than a bit of out-of-tram lines, my facemill give a beautiful finish.

That is an old tri-stone I used something like that when I was a young man. That was about 60 years ago.

Is there any reason to use the TPG insert (apart from convenience!) compared with a ground insert designed for aluminium, like CCGT or something? I'd assume that the cutting forces would be less with the ground insert, reducing vibration and giving a better finish.

In what situation would you choose a fly cutter over a face mill and vice versa

Maybe you needed that Abom sized fly cutter that Suburban Tools makes! Thanks for showing this (-8

Would the finish that this tooling produced be adequate for a vehicles cylinder head?

that dressing tool you have there is nice ,,,, thanks for the videos ,,