 |  | | | |  | |  |  | Rotation speed for brass? |  | |  |  | |
 Posted: Fri Aug 14, 2009 1:40 pm |
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| AirGunEric |
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| How fast should brass rod be spinning for the cleanest machining on a lathe? Any particular material that should be used, i.e. mild steel, carbide, whatever? |
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| Posted: Fri Aug 14, 2009 2:43 pm |
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| Alstone |
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I use a surface speed of 150 ft per minute, and a very sharp HS steel lathe tool and to get the best finish put a very slight lead on the tool face, this can be done with an oil stone it only needs a couple of thou.
Al
PS: I should have said that the above is for rough cutting, use 500 ft/minute for finishing. |
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| Posted: Mon Nov 09, 2009 10:38 pm |
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| nsanderson92 |
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| i take a machine shop class and whenever im turning brass i use carbide and turn it about 900 Rpm ...it leavs an awesome finish |
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| Posted: Tue Nov 10, 2009 4:35 am |
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| Alstone |
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| nsanderson92 wrote: |
| i take a machine shop class and whenever im turning brass i use carbide and turn it about 900 Rpm ...it leavs an awesome finish |
To get the right finish on brass it's the "fpm" and feed that makes the differences not the "rpm", the fpm stays the same but the rpm changers depending upon the diameter and the finish required on the work piece.
Most commercial machine shops use carbide to get long runs with out changing the tool, but for high quality and precision finishes on brass or bronze you can't beat self sharpened HSS tools, especially for the home hobbyist.
To prove my point try taking off .001" off a small brass shaft using a carbide cutter, most will just rub along the surface because they can't get a bite on the material, now try taking .050" and you will have no problem.
The thing is that commercial shops take a larger last cut as there finishing cut, they set up their lathe's to do it this way usually on long runs, where as the hobbyist maybe just wants to skim a few thou of a shaft or bush to get it to fit.
BTW welcome to AirGunHome.
Al |
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| Posted: Tue Nov 10, 2009 8:06 pm |
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| kanyon |
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| Alstone wrote: |
| nsanderson92 wrote: |
| i take a machine shop class and whenever im turning brass i use carbide and turn it about 900 Rpm ...it leavs an awesome finish |
To get the right finish on brass it's the "fpm" and feed that makes the differences not the "rpm", the fpm stays the same but the rpm changers depending upon the diameter and the finish required on the work piece.
Most commercial machine shops use carbide to get long runs with out changing the tool, but for high quality and precision finishes on brass or bronze you can't beat self sharpened HSS tools, especially for the home hobbyist.
To prove my point try taking off .001" off a small brass shaft using a carbide cutter, most will just rub along the surface because they can't get a bite on the material, now try taking .050" and you will have no problem.
The thing is that commercial shops take a larger last cut as there finishing cut, they set up their lathe's to do it this way usually on long runs, where as the hobbyist maybe just wants to skim a few thou of a shaft or bush to get it to fit.
BTW welcome to AirGunHome.
Al |
Yep..But not so easy when facing...Unless yer have
a constant surface speed lathe...... |
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| Posted: Tue Nov 10, 2009 8:37 pm |
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| Alstone |
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Yea but for facing you don't usually require the same degree of finish, as it's very rarely fitting in to something else
Plus for facing speed you would use 1/3 of the diameter as a starting point for calculating the feed, this of cause would only apply to large diameter work. CNC machines would veary the feed anyway.
Al  |
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| Posted: Wed Nov 11, 2009 9:12 pm |
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| dogon1013 |
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| Posted: Thu Nov 12, 2009 5:09 am |
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| Alstone |
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| dogon1013 wrote: |
I just cut it at whatever speed the lathe was last set at...that usually works. |
Exactly! And adjust if necessary, that how most people work once they are confidant in using a lathe.
What I was pointing out is that you use surface speed not rpm.
Al |
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