- Joined
- Jan 20, 2016
- Messages
- 602
I got one of those inexpensive digital microscopes on Amazon, and I have been having a great time looking at things up close and solving some not so mysterious mysteries. I am shocked at how well this thing works for what it costs and that you can connect it to your computer and view it as a webcam.
Have you ever wondered what the difference between a $1 insert and $20 insert? They look similar enough and both look like they would do the job you asked of them, but the $20 insert just lasts longer, seems to cut with less force, and gives you a better surface finish. Well when you look up close, it becomes far more clear why the results look the way they do.
This is a brand new APKT insert that costs about $12/10 pack. To the naked eye, it looks polished, sharp, and ready to cut.
But, if you get a little closer to have a look at the cutting edge, it is a different story. This particular insert has a nice little nick right in the middle of the cutting edge. That may be from lower quality carbide or just poor grinding, but that explains a lot!
Getting a little closer again, you can see that the radius on the edge isn't really a radius and it is very rough all the way around. This is where your surface finish will come from, so this explains why these inserts look like they would produce a perfect finish, but it just isn't quite right.
Pulling another random insert from the pack tells a similar story. The edges are all somewhat jagged, with some being a lot worse than others. Also, the odd discoloration on this one is my fingerprint. It is all CSI up in this crime lab.
Now looking at another insert, the picture is much better. This is a shearhog insert which goes for about $20/insert. This one is also brand new, never been used to cut.
This one was harder to get pictures of because it was a mirror on the front, but I was able to get a decent look at the edge. There are some imperfections, but overall, it has a proper radius cut on it and it is much smoother all the way through.
This one is a mini shear insert, also roughly $20/insert. The hair you see on it is lint from the tissue I used to wipe off my fingerprint. This one doesn't have near the same mirror finish as the full size shear hog, but it still looks much better.
Up close it has a bit of a nick right on the edge, but it is still a good looking radius with no jagged cuts. The little striations in the surface are also an interesting note. I am curious about the little color changes as it moves across.
So there ya have it. The cheaper inserts have poorly cut edges and lots of nicks and dings compared to the expensive ones. However, the $1 inserts work well enough for most cases. Whether the increase in insert life will be offset by the increase in cost (Can the shearhog last 20 times longer than the imports?) is a question for someone with far more experience than me.
I personally have not used a shearhog before, so I am only going off the experiences that others have posted. But the $1 inserts in a $30 tool (Compared to a $20 insert in a $250 tool) will leave a nice enough surface (not mirror, but it looks good) and can rip chunks off my workpieces on my small PM-25. I have been able to get it to remove 3-4 in^3/min before I start having tool pullout trouble.
Just for fun, here are a few close ups of some of the other inserts I had around.
This one is a 1003 size insert I use on a .75" end mill used mostly for facing and occasionally roughing. This insert was swapped out with the other 2 when it started having trouble with chip welding and the surface finishes were starting to go. I have no idea what the brown stuff on it is or how long I had been using it. It also came with a bunch of other inserts when I bought the end mill used, so I don't know the make or cost of the insert.
This is a look at the surface finish these inserts leave.
This is a Eurocut WNMG insert that I have used with success in a shop made aluminum holder on my 1030v lathe. It works pretty well, but I don't have the power to really take advantage of it.
This one is an inexpensive APMT 1604 that came with a $30 2 inch face mill. They don't work great, but I use the polished inserts instead.
This is a Sandvik R390 coated insert. I haven't used these before, but it looks good.
A $2ish threading insert. These work well and cut a nice thread.
This is an Alu-power 3 flute end mill. These are very shiny, very sharp, produce a nice surface finish, and can remove a surprising amount of material for a small mill. I think they are about $30 each.
This is a coated Niagra 3 flute end mill with a corner radius. They work pretty well also, but you really have to force them to cut or they chatter. I got these on ebay for $10 I believe.
And just in case you were wondering what a 99 cent end mill straight from China looks like, here it is. I hope you had your breakfast already because this thing is disgusting. This is what it looks like brand spankin new.
I have been having a great time with this thing so if anyone wants to see something up close, let me know and I will see what I can do.
Have you ever wondered what the difference between a $1 insert and $20 insert? They look similar enough and both look like they would do the job you asked of them, but the $20 insert just lasts longer, seems to cut with less force, and gives you a better surface finish. Well when you look up close, it becomes far more clear why the results look the way they do.
This is a brand new APKT insert that costs about $12/10 pack. To the naked eye, it looks polished, sharp, and ready to cut.
But, if you get a little closer to have a look at the cutting edge, it is a different story. This particular insert has a nice little nick right in the middle of the cutting edge. That may be from lower quality carbide or just poor grinding, but that explains a lot!
Getting a little closer again, you can see that the radius on the edge isn't really a radius and it is very rough all the way around. This is where your surface finish will come from, so this explains why these inserts look like they would produce a perfect finish, but it just isn't quite right.
Pulling another random insert from the pack tells a similar story. The edges are all somewhat jagged, with some being a lot worse than others. Also, the odd discoloration on this one is my fingerprint. It is all CSI up in this crime lab.
Now looking at another insert, the picture is much better. This is a shearhog insert which goes for about $20/insert. This one is also brand new, never been used to cut.
This one was harder to get pictures of because it was a mirror on the front, but I was able to get a decent look at the edge. There are some imperfections, but overall, it has a proper radius cut on it and it is much smoother all the way through.
This one is a mini shear insert, also roughly $20/insert. The hair you see on it is lint from the tissue I used to wipe off my fingerprint. This one doesn't have near the same mirror finish as the full size shear hog, but it still looks much better.
Up close it has a bit of a nick right on the edge, but it is still a good looking radius with no jagged cuts. The little striations in the surface are also an interesting note. I am curious about the little color changes as it moves across.
So there ya have it. The cheaper inserts have poorly cut edges and lots of nicks and dings compared to the expensive ones. However, the $1 inserts work well enough for most cases. Whether the increase in insert life will be offset by the increase in cost (Can the shearhog last 20 times longer than the imports?) is a question for someone with far more experience than me.
I personally have not used a shearhog before, so I am only going off the experiences that others have posted. But the $1 inserts in a $30 tool (Compared to a $20 insert in a $250 tool) will leave a nice enough surface (not mirror, but it looks good) and can rip chunks off my workpieces on my small PM-25. I have been able to get it to remove 3-4 in^3/min before I start having tool pullout trouble.
Just for fun, here are a few close ups of some of the other inserts I had around.
This one is a 1003 size insert I use on a .75" end mill used mostly for facing and occasionally roughing. This insert was swapped out with the other 2 when it started having trouble with chip welding and the surface finishes were starting to go. I have no idea what the brown stuff on it is or how long I had been using it. It also came with a bunch of other inserts when I bought the end mill used, so I don't know the make or cost of the insert.
This is a look at the surface finish these inserts leave.
This is a Eurocut WNMG insert that I have used with success in a shop made aluminum holder on my 1030v lathe. It works pretty well, but I don't have the power to really take advantage of it.
This one is an inexpensive APMT 1604 that came with a $30 2 inch face mill. They don't work great, but I use the polished inserts instead.
This is a Sandvik R390 coated insert. I haven't used these before, but it looks good.
A $2ish threading insert. These work well and cut a nice thread.
This is an Alu-power 3 flute end mill. These are very shiny, very sharp, produce a nice surface finish, and can remove a surprising amount of material for a small mill. I think they are about $30 each.
This is a coated Niagra 3 flute end mill with a corner radius. They work pretty well also, but you really have to force them to cut or they chatter. I got these on ebay for $10 I believe.
And just in case you were wondering what a 99 cent end mill straight from China looks like, here it is. I hope you had your breakfast already because this thing is disgusting. This is what it looks like brand spankin new.
I have been having a great time with this thing so if anyone wants to see something up close, let me know and I will see what I can do.
