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PM-1640TL problems getting reasonable surface finish
- Thread starter jeremysf
- Start date
- Joined
- Sep 28, 2013
- Messages
- 4,402
50 thou depth of cut
- Joined
- Mar 2, 2021
- Messages
- 84
A long nose center is a great addition to your work holding. I have this one from Shars for my TL and use it all the time on small parts.
Mine just arrived! Made by Rohm. I have been waiting for a few weeks for it to arrive, and was wondering if I was crazy buying one. Glad to have confirmation from you that I might be crazy, but in good company.
- Joined
- Mar 22, 2020
- Messages
- 175
Mine just arrived! Made by Rohm. I have been waiting for a few weeks for it to arrive, and was wondering if I was crazy buying one. Glad to have confirmation from you that I might be crazy, but in good company.
I have the exact same center. Got it for a really good price off Amazon. I never regret spending money on quality stuff. I have some Far East stuff that angers me just looking at it.
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- Mar 26, 2018
- Messages
- 8,759
The tapered tip is great for tool accessMine just arrived! Made by Rohm. I have been waiting for a few weeks for it to arrive, and was wondering if I was crazy buying one. Glad to have confirmation from you that I might be crazy, but in good company.
- Joined
- Apr 10, 2021
- Messages
- 621
I made the mistake of buying a normal one and now it sits in the drawer. The long nose works much better with my 5/8" tooling. Dave
Someone's gotta bite on this.
Live Center 60 Degree Morse Taper MT3 Röhm 1243505, Small Body Diameter and Profiled Center Point, Size 04, 15mm Point Diameter: Live Centers: Amazon.com: Industrial & Scientific
Live Center 60 Degree Morse Taper MT3 Röhm 1243505, Small Body Diameter and Profiled Center Point, Size 04, 15mm Point Diameter: Live Centers: Amazon.com: Industrial & Scientific
www.amazon.com
- Joined
- Jun 12, 2014
- Messages
- 5,134
I already bit on that one, now out of stock, say more on the way HA! I had the older bigger diameter Shar's CNC and it is very bulky and always was a bit gritty and stiff in the bearing after several years of use. Rohm makes great tools and you will be very happy with an extended point, I use it most of the time except for heavy loads. All a learning curve for all of us, when you think you know it all, then you are really fooling yourself.
On the surface finish issues, it is a combination of both speed and feed with the particular insert geometry. Hugh difference between the same style of inserts. Also for the nose diameter there is a particular feed that will give the best surface finish for different materials. Example below is HR 4140 initially had a feed of around 0.004"/r and then doubled it to 0.008"/r using and Iscar CCMT 32.51 IC907 coating. I find it to be a very good all around turning insert, and switch to a CCGT when I need to do very fine light DOC cutting. I did some recent turning with CR 1018 and got a very good finish, despite hating to turn that metal. I also think your insert does not have a sharp enough cutting edge or positive rake to cut the metal you show, and often you need a different insert for different materials. Get yourself something like a 10X magnifier so you can inspect the cutter tip/edge, you will be surprised how often that when you have a poor finish the tip is damaged or loaded up an not longer cutting. Light cutting fluid also helps. I made my own FogBuster unit for my mill, big difference, and I may add one to my lathe at some point.
Also understanding the chips coming off both type and color is important to know how you are cutting. You definitely can't fault the lathe in this case.
On the surface finish issues, it is a combination of both speed and feed with the particular insert geometry. Hugh difference between the same style of inserts. Also for the nose diameter there is a particular feed that will give the best surface finish for different materials. Example below is HR 4140 initially had a feed of around 0.004"/r and then doubled it to 0.008"/r using and Iscar CCMT 32.51 IC907 coating. I find it to be a very good all around turning insert, and switch to a CCGT when I need to do very fine light DOC cutting. I did some recent turning with CR 1018 and got a very good finish, despite hating to turn that metal. I also think your insert does not have a sharp enough cutting edge or positive rake to cut the metal you show, and often you need a different insert for different materials. Get yourself something like a 10X magnifier so you can inspect the cutter tip/edge, you will be surprised how often that when you have a poor finish the tip is damaged or loaded up an not longer cutting. Light cutting fluid also helps. I made my own FogBuster unit for my mill, big difference, and I may add one to my lathe at some point.
Also understanding the chips coming off both type and color is important to know how you are cutting. You definitely can't fault the lathe in this case.
