the 1 st tool bit

jam

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the 1 st tool bit that I sharpen by hand this is how it cut a 1 1/2 rodIMG_0048.JPGIMG_0051.JPG not the best but a start

IMG_0048.JPG IMG_0051.JPG
 
Good morning Jam,

That finish looks great from here... :thumbzup: You must have had a smile of satisfaction on your face after your first tool bit grind worked out so well.

Cheers.... :)

Brian
 
Very good... Keep practicing. For extra credit, make-up a target diameter and see if you can turn down precisely to that value -regardless of what the finish looks like. And for extra-extra credit, practice turning it down to a known diameter with different finish types.


Good work... Be Safe, Have Fun.


Ray
 
Looks good, Let's see a photo of what your tool bit looks like!
 
Nice work my man.

Ray, would you mind talking a bit about how to get different finishes?
Very good... Keep practicing. For extra credit, make-up a target diameter and see if you can turn down precisely to that value -regardless of what the finish looks like. And for extra-extra credit, practice turning it down to a known diameter with different finish types.


Good work... Be Safe, Have Fun.


Ray
 
Nice work my man.

Ray, would you mind talking a bit about how to get different finishes?

OK, I can start the discussion now but, I have errands today. Also, I want others to write in and share their experiences as we can all learn...


I want to reiterate that it's more important at first to attain the ability to turn to a specific diameter regardless of the finish. There are different things to learn and if you take it step-by-step like this, you will not encounter evolving, simultaneous problems. Also, I'm not an expert on using high-speed-steel bits. I do indeed use them for specific purposes but not for general purpose cutting; as such, my bag of tricks is limited.

Keep in mind that as you turn a piece of unknown metal, several things are going on. Since the metal is unknown, it may have layers of hardness that impact finish. Harder metal cuts with a cleaner finish (up to a point -but then gets ragged for really hard metal) and as you cut into it, the piece evolves as you reach the softer core. Also, as the diameter decreases, you need to adjust your RPMs to attain the proper SFM cutting rate. This adds a layer of variability if you have a machine with few speed steps or don't have a variable speed lathe.

Keep the above things in mind as you progress.

In general rougher finishes are done with a pointier bit and a slightly faster feed rate. Smoother finishes are the opposite... slightly rounded point with moderate to slower feed rates. On smooth finishes, the vibration in your lathe setup makes all the difference in the world -so that's a area to watch out for.

The real battles to overcome in either case, is knowing what feed/speed to use and depth of cut. When I come back, I'll cover some examples. Later today, I was planning on setting-up some HSS bit holders because, in the last couple weeks, they've gotten out of whack. I'll take some pics... In the mean time, others are encouraged to share their thoughts....


Ray
 
Good job, your off to a running start. Its only gonna get better.
 
Hitting the marks never been an issue for me. Most anything I have turned has come out in the .0001 range. If it dont, I was simply not paying attention good enough I figure. Feeds and speeds on the other hand is something I need to work on.

Now you mention slowing the feed gives a better finish. Would one need to slow the spindle speed as you slow the feed? Or simply just slow the feed rate?

You can look at a cross section of our class projects and clearly see a range of finishes. All perfectly acceptible for our level and what we are making, but clearly some better then others. Some with more tooling marks, some with more shine.

Thanks for taking the time. If need be I can start a thread on it if the op dont want us OT in his thread
 
You can look at a cross section of our class projects and clearly see a range of finishes. Some with more tooling marks, some with more shine.

If your fellow students are taking notes and will share with others I believe you will find some answers. Also your instructor should be
able to help. It would be nice to compare notes and ask questions such as "what were the settings, feed, speed, tool shape, ect,"
 
Hitting the marks never been an issue for me. Most anything I have turned has come out in the .0001 range. If it dont, I was simply not paying attention good enough I figure. Feeds and speeds on the other hand is something I need to work on.

Now you mention slowing the feed gives a better finish. Would one need to slow the spindle speed as you slow the feed? Or simply just slow the feed rate?

You can look at a cross section of our class projects and clearly see a range of finishes. All perfectly acceptible for our level and what we are making, but clearly some better then others. Some with more tooling marks, some with more shine.

Thanks for taking the time. If need be I can start a thread on it if the op dont want us OT in his thread

Unless you own a Hardinge HLV-H or something similar, the feed on you lathe is set in "/Rev. In essence, you are always cutting threads on a lathe, just most of the time the pitch is so fine that you can't see it. So when you reduce the feed on a lathe to get a better finish you are reducing the "pitch" of your thread to the point where it no longer matters.
 
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