Bushing material question
-
- Posts: 2366
- Joined: Tue Jan 20, 2009 9:33 pm
- Location: Phoenix ,AZ
- seal killer
- Posts: 4696
- Joined: Sat Aug 18, 2007 10:58 pm
- Location: Ozark Mountains
Re: Bushing material question
Harold and All--
[Note to All: This is taking a long time because I am not in a hurry and my primary objective is to continue learning, especially as I've been away from my shop for years. I appreciate you sticking with me and all the help you give.]
I took your advice on ditching the insert-based tool. I found tool I had either bought or ground long ago that looked right to me. I tried it on the face of the phosphor bronze work piece with good results . . .
Next I tried it on the diameter of the workpiece with very poor results . . . Here is a closeup of the cutter (I can take far better pictures of all, if needed) . . . Can you tell where I've gone wrong on improving the finish on the diameter?
Thank you.
--Bill
[Note to All: This is taking a long time because I am not in a hurry and my primary objective is to continue learning, especially as I've been away from my shop for years. I appreciate you sticking with me and all the help you give.]
I took your advice on ditching the insert-based tool. I found tool I had either bought or ground long ago that looked right to me. I tried it on the face of the phosphor bronze work piece with good results . . .
Next I tried it on the diameter of the workpiece with very poor results . . . Here is a closeup of the cutter (I can take far better pictures of all, if needed) . . . Can you tell where I've gone wrong on improving the finish on the diameter?
Thank you.
--Bill
You are what you write.
Re: Bushing material question
I see a couple things with the tool that may be an issue. First is that the chip breaker appears to have yielded negative rake. That may or may not be an illusion, however. A photo of the end of the tool taken in line with the tool would reveal the actual geometry. The second thing is obvious---the tool has no radius, and that's important if you hope to achieve a fine finish. Simply honing the tool to improve surface finish should make a difference, and the recommended radius could then be created. It doesn't take a lot, even ten thou makes a huge difference.
A second look gives me cause to ask----is there any relief on the end of the tool? It has a tendency to look as if there is not. A square end will not perform well.
H
A second look gives me cause to ask----is there any relief on the end of the tool? It has a tendency to look as if there is not. A square end will not perform well.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
- seal killer
- Posts: 4696
- Joined: Sat Aug 18, 2007 10:58 pm
- Location: Ozark Mountains
Re: Bushing material question
Harold and All--
Sorry for taking so long to get back to this issue. I brush hogged a few acres for a neighbor and graded the road and . . .
Harold, do these pictures tell you what you need to know? The cutter has no visible radius, but it does have clearance.
No radius . . . Clearance . . . --Bill
Sorry for taking so long to get back to this issue. I brush hogged a few acres for a neighbor and graded the road and . . .
Harold, do these pictures tell you what you need to know? The cutter has no visible radius, but it does have clearance.
No radius . . . Clearance . . . --Bill
You are what you write.
Re: Bushing material question
If I can safely assume that the tool has an equal amount of relief on the side, then that issue is likely moot, but I am troubled by the chip breaker, which appears to turn negative all too quickly. This material will respond better to being shorn than it will to being pushed by negative rake, although excessive positive rake can create its own issues. A balance of positive rake and limited relief will generally prevent self feeding, however. Here's a picture of what I'd suggest is acceptable in chip breaker form:
A sharp corner will rarely provide a decent finish, but with any top rake on a cutting tool one must limit the amount of radius, as the cutting edge moves away from center rapidly. At a minimum, the tool should be honed on both the front and cutting side, then a minimal radius stoned on. If the tool geometry is correct, the top and bottom edges will provide a guide for stoning, so the cutting edge isn't rounded beyond being useful. I'm talking about rounding that removes relief in this instance, not the size of the radius. Ten thou would be an acceptable tip radius in this case, but maintaining the necessary relief.
H
A sharp corner will rarely provide a decent finish, but with any top rake on a cutting tool one must limit the amount of radius, as the cutting edge moves away from center rapidly. At a minimum, the tool should be honed on both the front and cutting side, then a minimal radius stoned on. If the tool geometry is correct, the top and bottom edges will provide a guide for stoning, so the cutting edge isn't rounded beyond being useful. I'm talking about rounding that removes relief in this instance, not the size of the radius. Ten thou would be an acceptable tip radius in this case, but maintaining the necessary relief.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
- seal killer
- Posts: 4696
- Joined: Sat Aug 18, 2007 10:58 pm
- Location: Ozark Mountains
Re: Bushing material question
Harold and All--
I'm back. I have been grading the road and other stuff. My internet connection has been worthless. (Hughesnet.) Another reason is that it has been over a hundred here. The shop is not air conditioned, yet.
I followed Harold's advice about the clearances and bit radius with great results. My photo could be better. I was lazy and used my V60 ThinQ which is supposed to have a great camera. It does. Maybe not for closeup work, though. I should have got the Nikon out with the closeup lens. Next time.
Anyway, take a look . . .
--Bill
I'm back. I have been grading the road and other stuff. My internet connection has been worthless. (Hughesnet.) Another reason is that it has been over a hundred here. The shop is not air conditioned, yet.
I followed Harold's advice about the clearances and bit radius with great results. My photo could be better. I was lazy and used my V60 ThinQ which is supposed to have a great camera. It does. Maybe not for closeup work, though. I should have got the Nikon out with the closeup lens. Next time.
Anyway, take a look . . .
--Bill
You are what you write.
- Bill Shields
- Posts: 10582
- Joined: Fri Dec 21, 2007 4:57 am
- Location: 39.367, -75.765
- Contact:
Re: Bushing material question
Too many things going on to bother listing them.
- seal killer
- Posts: 4696
- Joined: Sat Aug 18, 2007 10:58 pm
- Location: Ozark Mountains
Re: Bushing material question
All and Bill--
Better pictures . . .
I increased the clearance on the indicated faces and increased the radius . . .
--Bill
Better pictures . . .
I increased the clearance on the indicated faces and increased the radius . . .
--Bill
You are what you write.
Re: Bushing material question
Excellent!
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
Operating machines is perfectly safe......until you forget how dangerous it really is!
-
- Posts: 2366
- Joined: Tue Jan 20, 2009 9:33 pm
- Location: Phoenix ,AZ
- seal killer
- Posts: 4696
- Joined: Sat Aug 18, 2007 10:58 pm
- Location: Ozark Mountains
Re: Bushing material question
All--
Here's a video I made while in the process of making those phosphor bronze bushings. I made it the day after I finished the bushings, but could not upload it given my horrible internet service. So I waited until we went to KC to see our kids and used our daughter's gigabit connection to upload it.
So, if you are interested . . .
https://youtu.be/aaXI3npnLA0
And thank you again for all the help!
--Bill
Here's a video I made while in the process of making those phosphor bronze bushings. I made it the day after I finished the bushings, but could not upload it given my horrible internet service. So I waited until we went to KC to see our kids and used our daughter's gigabit connection to upload it.
So, if you are interested . . .
https://youtu.be/aaXI3npnLA0
And thank you again for all the help!
--Bill
You are what you write.
Re: Bushing material question
Nice video, Bill.
The tool you ground that was used at about 45 minutes looked real good. The cut was clean and shiny, as it should be.
In the end, when you were trying to chamfer the bore, I suspect that the tool was dragging at the bottom, judging by the burr that was being created in the cut. Could be wrong. Such cuts are often difficult in small diameters because of the rapid change in clearance due to the small radius involved. Larger bores are far more forgiving. The cut should create a slight burr, but it will be bright and uniform when the tool is correct, not frosty as it was in the video.
Assuming the tool was dragging a little, there's nothing wrong with raising it a little above center to create a little more clearance. A keen edge is really helpful when cutting this material.
Well done!
H
The tool you ground that was used at about 45 minutes looked real good. The cut was clean and shiny, as it should be.
In the end, when you were trying to chamfer the bore, I suspect that the tool was dragging at the bottom, judging by the burr that was being created in the cut. Could be wrong. Such cuts are often difficult in small diameters because of the rapid change in clearance due to the small radius involved. Larger bores are far more forgiving. The cut should create a slight burr, but it will be bright and uniform when the tool is correct, not frosty as it was in the video.
Assuming the tool was dragging a little, there's nothing wrong with raising it a little above center to create a little more clearance. A keen edge is really helpful when cutting this material.
Well done!
H
Wise people talk because they have something to say. Fools talk because they have to say something.