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End Mill Sharpener ?
- Thread starter rdean
- Start date
- Joined
- Feb 2, 2014
- Messages
- 1,069
I found that in fact the table was too high even after trying to keep it low it just wouldn't work. With the barrel tipped up 20 degrees the end of a long end mill was well above the grinder center line. So I raised the grinder 1 1/2" with a 2 X 12 block. (can't lower the table so raise the grinder)
I cut about 6" off the tower that wasn't needed and lagged it all to the work bench. The bench was made about 10 years ago for the wife as she wanted somewhere to do her own thing. Well that lasted about a month until she had her own 12X24 workshop delivered. (if mama isn't happy then nobody is happy)
So this work bench was mainly for the grinder.
Time to make the indexer pin that follows the end mill spiral.
This is what I started with.
And here it is installed and after making a couple of passes.
First one with flutes sharpened.
Tried another mill with the before and after pictures.
All of these end mills had been sharpened professionally several times before and were past their minimum size specifications so I got them really cheap.
I then grabbed a 3/8" 4 flute end mill and tried to sharpen it. I noticed that when I started to grind a flute the end was not touching the wheel but at the shank end it was cutting quite deeply. I continued on until I knew there was something wrong. I had made a tapered end mill. The barrel lock was not holding and the barrel had tipped down about 10 degrees which brought the cutting end closer to the wheel and so it cut deeper or in a taper.
Now to stop and fix some of the problems I have found.
#Barrel Lock
#Move the table 2" closer to the grinder
#Make a lock for each of the X and Y axis (they don't stay where you put them)
#The index pin shaft needs to be longer
Probably 10 other things I haven't found yet.
Question I have the center line of the end mill set about 1/2" above the center line of the wheel. Is this about right for sharpening the flutes?
Thanks for looking
Ray
I cut about 6" off the tower that wasn't needed and lagged it all to the work bench. The bench was made about 10 years ago for the wife as she wanted somewhere to do her own thing. Well that lasted about a month until she had her own 12X24 workshop delivered. (if mama isn't happy then nobody is happy)
So this work bench was mainly for the grinder.
Time to make the indexer pin that follows the end mill spiral.
This is what I started with.
And here it is installed and after making a couple of passes.
First one with flutes sharpened.
Tried another mill with the before and after pictures.
All of these end mills had been sharpened professionally several times before and were past their minimum size specifications so I got them really cheap.
I then grabbed a 3/8" 4 flute end mill and tried to sharpen it. I noticed that when I started to grind a flute the end was not touching the wheel but at the shank end it was cutting quite deeply. I continued on until I knew there was something wrong. I had made a tapered end mill. The barrel lock was not holding and the barrel had tipped down about 10 degrees which brought the cutting end closer to the wheel and so it cut deeper or in a taper.
Now to stop and fix some of the problems I have found.
#Barrel Lock
#Move the table 2" closer to the grinder
#Make a lock for each of the X and Y axis (they don't stay where you put them)
#The index pin shaft needs to be longer
Probably 10 other things I haven't found yet.
Question I have the center line of the end mill set about 1/2" above the center line of the wheel. Is this about right for sharpening the flutes?
Thanks for looking
Ray
If you are grinding the flutes on the periphery (outside) of the wheel, you start with the center of the spindle the same height as the center of the wheel. The flute rest is also set at this height to start.Then depending on the diameter of the end mill, you LOWER the flute rest several thousandths. The diameter of the wheel also enters into it. I have a chart somewhere that I downloaded giving some of these values. That is the reason I grind mills on the face of the wheel. It is much easier to set up. No fussing with the curve and diameter of the wheel. When sharpening you have to watch the width of the lands. If they get too wide then you must also grind the secondary angle.
I have been making an instruction manual for sharpening tools from info gathered from many sources. I will send what I have so far if you want, but it deals with grinding on the face of the wheel.
I have been making an instruction manual for sharpening tools from info gathered from many sources. I will send what I have so far if you want, but it deals with grinding on the face of the wheel.
- Joined
- Dec 22, 2015
- Messages
- 561
This whole build has been very impressive!!! Bookmarked for a possible future project. But first there is a lot of learning and practice required.
Thanks for posting this Ray.
Thanks for posting this Ray.
- Joined
- Mar 20, 2014
- Messages
- 440
I would just like to say that I, and probably many, many others would be very interested in seeing your instruction manual, once it ie completed. Hope you will post it, for all to benifite from your extreem knowlage. Thanks, and happy machining, JR49
- Joined
- Feb 2, 2014
- Messages
- 1,069
Reworked the barrel lock by moving the stop 1" out from the center.
This is the plate and the plate installed so problem solved.
When doing the flutes the X Y table is adjusted where you want them and then not moved again until all the flutes are cut for each pass. My tables were moving on me and I needed a lock to hold them in place but because of the way the table is made on the rods there is no simple solution. I made up this cam just to see how it would work and try to incorporate it into the design. I may not do any thing else to it as it works so good and is only needed when doing the flutes. Even in the locked position I can still adjust the Y axis for each pass on the flutes.
I was always told that when sharpening anything you should push the metal back into itself but with end mills that is just the opposite. I put the grinder in reverse and all my problems with the flutes disappeared. The wheel direction helps to keep the index flute against the index pin and smooths things out.
Up until now I have been just playing around with different settings and angles to see what works best. Did a lot of reading and studying so here goes the official full end mill sharpening. I chose a 3/4" two flute and a 1/2" four flute end mill for the test.
Sorry didn't get any pictures of the 1/2" 4 flute but the real test is how does it cut?
Cuts were made on a old RF31 and fed manually so I could feel how hard it was cutting. As you can see from the large chips both worked great with little effort.
The 3/4" slot was 0.075 deep and plunged in nicely. The 1/2" didn't want to plunge much more than 0.025 so I just restarted off the edge of the metal at a depth of 0.125. I still need some work on cutting the negative angle to the center of the end mill.
Well that's about it I still need to make a few changes to get it more user friendly and I don't think I will be sharpening anything smaller than 2 flute 1/4". It does work but would be better with a heavy manufactured X Y table and a different stone. It will be just fine for my needs and total out of pocket including a diamond wheel dresser is $30.
I had a great time building and learning from this project and appreciate all the help along the way.
Thanks again for looking.
Ray
This is the plate and the plate installed so problem solved.
When doing the flutes the X Y table is adjusted where you want them and then not moved again until all the flutes are cut for each pass. My tables were moving on me and I needed a lock to hold them in place but because of the way the table is made on the rods there is no simple solution. I made up this cam just to see how it would work and try to incorporate it into the design. I may not do any thing else to it as it works so good and is only needed when doing the flutes. Even in the locked position I can still adjust the Y axis for each pass on the flutes.
I was always told that when sharpening anything you should push the metal back into itself but with end mills that is just the opposite. I put the grinder in reverse and all my problems with the flutes disappeared. The wheel direction helps to keep the index flute against the index pin and smooths things out.
Up until now I have been just playing around with different settings and angles to see what works best. Did a lot of reading and studying so here goes the official full end mill sharpening. I chose a 3/4" two flute and a 1/2" four flute end mill for the test.
Sorry didn't get any pictures of the 1/2" 4 flute but the real test is how does it cut?
Cuts were made on a old RF31 and fed manually so I could feel how hard it was cutting. As you can see from the large chips both worked great with little effort.
The 3/4" slot was 0.075 deep and plunged in nicely. The 1/2" didn't want to plunge much more than 0.025 so I just restarted off the edge of the metal at a depth of 0.125. I still need some work on cutting the negative angle to the center of the end mill.
Well that's about it I still need to make a few changes to get it more user friendly and I don't think I will be sharpening anything smaller than 2 flute 1/4". It does work but would be better with a heavy manufactured X Y table and a different stone. It will be just fine for my needs and total out of pocket including a diamond wheel dresser is $30.
I had a great time building and learning from this project and appreciate all the help along the way.
Thanks again for looking.
Ray
Last edited:
Very nice Ray,
I'm impressed. I was worried about how well the flutes would sharpen because of the siding holder. That is why air bearings are widely used because if the slide sticks and doesn't move smooth your flute will have uneven edge and would show when cutting with the side of the mill. The are some sharpeners that do not use air bearings but they have a well lapped slide. I'm glad yours performed well. It is recommended to grind so the wheel direction helps keep the flute against the rest. It is recommended to stone the tiny burr left on the edge but it will come off when cutting. In the photos, your lands look a little wide. They should be around .030". If too wide it hurts the cutting efficiency. But all in all I think you have done a fantastic job. The hard part is learning to use it now.
I'm impressed. I was worried about how well the flutes would sharpen because of the siding holder. That is why air bearings are widely used because if the slide sticks and doesn't move smooth your flute will have uneven edge and would show when cutting with the side of the mill. The are some sharpeners that do not use air bearings but they have a well lapped slide. I'm glad yours performed well. It is recommended to grind so the wheel direction helps keep the flute against the rest. It is recommended to stone the tiny burr left on the edge but it will come off when cutting. In the photos, your lands look a little wide. They should be around .030". If too wide it hurts the cutting efficiency. But all in all I think you have done a fantastic job. The hard part is learning to use it now.