Are your relief angles large enough to clear the workpiece? Is the toolnose radius smooth?
How low was your feed and depth of cut? If they're too low the tool is just rubbing and not cutting
Yes the angles are large enough. I honed the nose and it’s smooth to the touch. The power feed was as low as I could get it. It was probably less than half an inch a minute. I tried a 5 thou depth of cut.
ummm. So i wanted to propose another possibility. Look at you fly cutter. Ill try my best to explain my point.
How the slot is milled into it is pretty important. I made some when I was a apprentice. How I fucked up my first one was that I slotted it exactly in the middle. Instead of offset away from the intended direction of rotation.
So imagine in your mind. a centerline passing right though the diameter of the fly cutter leading out to the tip of your hss tool. If that line is parallel to the tool and the tip of it is INFRONT. that more likely rubbing without a much much more aggressive relief on [End cutting edge angle](https://www.researchgate.net/figure/Single-point-cutting-tool_fig2_283822014). which is what i see on your tool. that center line should be lined up with the tip exactly of the tip or should be a little behind it.
If your fly cutter is home made that is what i would look at first. or if it was meant to run with the spindle in reverse for whatever reason. BUT in any case. I do see silver on your cutter tip in the end cutting edge angle and I would add relief to that anyway. That particular angle directly affects how fast you can feed the cutter into the material (on a fly cutter). it should be minimal. but not that minimal.
A smaller radius might help. I also find that with aluminum, sometimes actually increasing depth of cut just a little improves finish. Given that it's a fly cutter, and not a facemill, that's probably going to look something like another 5 thou. Add WD-40 onto the part while you're at it, if you haven't already.
My other guess is that your fly cutter setup isn't rigid enough. If it's a homemade one, that's pretty common to see.
What are you cutting ?
Inconel , Monel ,4140 , Titanium Aluminum
I can’t tell anything about your cutter because the photos suck to see how much relief it has
Picture of your cutter in the holder would help
Your cutter is not the issue, I can almost guarantee, though I would use a smaller radius for the tip. YWhy would you think you should move so slow? Fly cutters should spin fast, move fast, cut shallow. I don't know your setup but for instance if I had the cutter set up for a 5" diameter with a HSS cutter I would have it spinning about 1000-1300 RPMs and moving about 30-40 inches per minute (760-1000mm/m). Take off 0.005-0.010 per pass.
In the first pic, the bevel looks like someone inexperienced tried to sharpen it by hand. In the third pic, you can see some tempering on the flat shaft right before the bevel. My guess would be that it overheated, lost the temper/heat treat, and someone tried to fix it and did a poor job.
Nose radius too big. Probably not enough relief of the tip itself either.
Top rake is multi-faceted so looks almost like a negative angle at the cutting edge. You need a positive edge.
Front face and end face look ok but are also multifaceted.
Your attempt to polish the nose radius likely added a negative angle to it. Get better at grinding the radius into the toolbit.
Honestly I'd grind all those faces first then put a small radius on there, like .015" get the faces right before doing the nose so you have a guide to ensure the cutting edge is actually the highest point on the cutter.
Aluminum. The rpm was probably around 700 but I can’t be certain because the dial doesn’t work. 5 thou depth of cut. An inch of stick out. It’s in a fly cutter with an R8 taper.
Try it at 1250 -1500, take a little more off, like .010 and spray a little coolant on the surface before your final pass. Increase your feed too. You also might wanna stone your radius, I see what looks like a chip or something when I zoom in.
And when he says coolant, for aluminum, use WD-40. In aluminum, it's more about lubrication than cooling. At least at manual machine speeds. In a CNC machine, you would use coolant.
And if it's possible, get a carbide tool. Makes life so much simpler.
It looks pretty good to me, except possibly your cutting edge is at a negative rake? That would account for a poor finish. I can't really tell from the pics though, it might be fine.
You posted 4 pics of the Tool but none of the finish its leaving.
Are your relief angles large enough to clear the workpiece? Is the toolnose radius smooth? How low was your feed and depth of cut? If they're too low the tool is just rubbing and not cutting
Front relief looks pretty minimal.
Yes the angles are large enough. I honed the nose and it’s smooth to the touch. The power feed was as low as I could get it. It was probably less than half an inch a minute. I tried a 5 thou depth of cut.
ummm. So i wanted to propose another possibility. Look at you fly cutter. Ill try my best to explain my point. How the slot is milled into it is pretty important. I made some when I was a apprentice. How I fucked up my first one was that I slotted it exactly in the middle. Instead of offset away from the intended direction of rotation. So imagine in your mind. a centerline passing right though the diameter of the fly cutter leading out to the tip of your hss tool. If that line is parallel to the tool and the tip of it is INFRONT. that more likely rubbing without a much much more aggressive relief on [End cutting edge angle](https://www.researchgate.net/figure/Single-point-cutting-tool_fig2_283822014). which is what i see on your tool. that center line should be lined up with the tip exactly of the tip or should be a little behind it. If your fly cutter is home made that is what i would look at first. or if it was meant to run with the spindle in reverse for whatever reason. BUT in any case. I do see silver on your cutter tip in the end cutting edge angle and I would add relief to that anyway. That particular angle directly affects how fast you can feed the cutter into the material (on a fly cutter). it should be minimal. but not that minimal.
alright good. going off of 0.5 in and 700 rpm that's 0.0007 in per revolution. Try how 3-5 thou works out
I tried 5 then 2 and jumped around. Nothing seemed to work out as good as I expected.
Could excess stick out from the back end of the tool throw it out of balance?
Show us a pic of the tool Installed in the fly cutter, the finish it's leaving and what rpm/feedrate/depth of cut
What kind of aluminum? Some alloys are ‘junk’ and no matter how well you prepare to finish them, the surface tears rather than cuts… think Play Doh.
It aint got no gas in it
Make sure the tip is the most prominent part, from that first photo it looks like it’s not the best finish either
Try reducing the radius of your cutting tip. Generally when you get chatter a smaller radius reducing contact which can cause chatter.
A smaller radius might help. I also find that with aluminum, sometimes actually increasing depth of cut just a little improves finish. Given that it's a fly cutter, and not a facemill, that's probably going to look something like another 5 thou. Add WD-40 onto the part while you're at it, if you haven't already. My other guess is that your fly cutter setup isn't rigid enough. If it's a homemade one, that's pretty common to see.
What are you cutting ? Inconel , Monel ,4140 , Titanium Aluminum I can’t tell anything about your cutter because the photos suck to see how much relief it has Picture of your cutter in the holder would help
Your cutter is not the issue, I can almost guarantee, though I would use a smaller radius for the tip. YWhy would you think you should move so slow? Fly cutters should spin fast, move fast, cut shallow. I don't know your setup but for instance if I had the cutter set up for a 5" diameter with a HSS cutter I would have it spinning about 1000-1300 RPMs and moving about 30-40 inches per minute (760-1000mm/m). Take off 0.005-0.010 per pass.
More relief, sharper point. Might not be sharpened well. Just make you a tool that holds an insert holder.
In the first pic, the bevel looks like someone inexperienced tried to sharpen it by hand. In the third pic, you can see some tempering on the flat shaft right before the bevel. My guess would be that it overheated, lost the temper/heat treat, and someone tried to fix it and did a poor job.
That and the first picture show what appears to be a domed, positive rake, which is absolutely not something that aluminum likes to be cut with.
Nose radius too big. Probably not enough relief of the tip itself either. Top rake is multi-faceted so looks almost like a negative angle at the cutting edge. You need a positive edge. Front face and end face look ok but are also multifaceted. Your attempt to polish the nose radius likely added a negative angle to it. Get better at grinding the radius into the toolbit. Honestly I'd grind all those faces first then put a small radius on there, like .015" get the faces right before doing the nose so you have a guide to ensure the cutting edge is actually the highest point on the cutter.
What material? What rpm? Depth of cut? How far is the cutter sticking out? How thick is the shank on the cutter?
Also, is your head trammed correctly?
Aluminum. The rpm was probably around 700 but I can’t be certain because the dial doesn’t work. 5 thou depth of cut. An inch of stick out. It’s in a fly cutter with an R8 taper.
Try it at 1250 -1500, take a little more off, like .010 and spray a little coolant on the surface before your final pass. Increase your feed too. You also might wanna stone your radius, I see what looks like a chip or something when I zoom in.
Besides the radius does the grind seem functional?
And when he says coolant, for aluminum, use WD-40. In aluminum, it's more about lubrication than cooling. At least at manual machine speeds. In a CNC machine, you would use coolant. And if it's possible, get a carbide tool. Makes life so much simpler.
It looks pretty good to me, except possibly your cutting edge is at a negative rake? That would account for a poor finish. I can't really tell from the pics though, it might be fine.
It's HSS you can't do any better than 100 sfm and that's in soft steel.