Speeds and Feeds Question

Do I understand that the magnet is to hold the chuck key in the chuck? I would run away from that! I hope I'm mistaken. I was taught not to remove my hand from the chuck without the key in the hand. To NEVER leave the key in the chuck.
 
So this is specific to this type of chuck, I spin my chuck 180 degrees by hand with both keys opposite each other. Without the magnets the keys would fall out as it swings under the chuck turning by hand. I use the dial gauge and can quickly split the difference between the two opposing keys and also need to feel the tension on both. This is much faster then removing the keys and then putting them back in after the chuck is turned. The size and design of the keys are short as to not hit anything when they are inserted and one is swinging the chuck. These are also very small key heads and one needs to fumble to insert the rear chuck key if it is removed. Rest assured I am both meticulous about safety and only have the key(s) in the chuck when setting the TIR with BOTH hands on the chuck. I remove the key(s) even if I need to go to my bench or get something. There is no one else that uses the machine or has access, and the magnetic keys is only specific to this chuck and cannot be used on any other chuck. Whether it has a magnet or not makes no difference if you leave a chuck key in the chuck and turn on the lathe.
 
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I spent about 30 years of my woking life indicatinlg a four jaw cuck with one wrench. Have been doing the same since retirement in 2000. Just thinking about TWO wrenches flying out of a chuck.... Hoo Boy! Well, nevermind.
Boy.
 
If you are really worried, and have a VFD program it for a super slow start up( 20 seconds or more). That'll give you time to shut down or even remove them as they spin at 1 rpm, put orange tape on chuck shank, spin chuck by hand every time before you start.:angel:
 
Speeds and feeds for inserts are centered more around production machines and high Hp, as opposed to smaller lathes. I usually run my lathe speeds/feeds at about 1/4-1/2 of what is printed on the insert boxes. Feeds are predominately around 0.004"/rev, with a range of 0.007-0.002"/rev. The DOC is often determined by the insert nose diameter and also if the insert is molded (CCMT) vs ground (CCGT), the latter being much sharper and able to take finer cuts without the nose of the insert deflecting from the work. I typically use a 32.51 insert size, so typically the minimum DOC is around 0.002, the maximum cut on the 1340GT is in the range of 0.1-0.15 diameter with a feed in the 0.004-5" range. I rarely use a 32.52 insert, dut it requires a slightly deeper cut probably on the order of 0.004-0.006", and give a very nice finish. A CGGT type can take a smaller depth cut, but I would get these inserts on different materials to get a feel of DOC and feed for your machine. Aluminum you can push faster speeds. The brand/quality of the insert can make a significant difference in how well they work. My go to insert for all steel (they will also work ok in aluminum) is an Iscar ISCAR CCMT 32.51 or 3-2-SM IC907 CCMT09T308-SM
https://www.ebay.com/itm/10-pcs-ISCAR-CCMT-3-2-SM-IC907-CCMT09T308-SM/323271443088

On 3/4" stock I am running the RPM in the 600-800 RPM range for O1 steel, aluminum you can turn faster but I get a clean cut also at this RPM. On steel you can look at the chips to see the color (straw color, then turning blue after they come off) to see if you are pushing too hard. Higher feed rates will help break the chips into C's as opposed to long strings, but sometimes the machine does not have the ultimate power and rigidity to remove high volumes of materials. Every material turns differently and will show a remarkable difference in finish based on speed and feed, I found with steel I needed to increase my feed rate to around 0.004-0.005"/rev gave a much better finish then slower feeds. When targeting a final dimension, as I get closer to the target dimension I will take something like one or two 0.01" passes and look at my DRO reading and measure the actual cut diameters to compare the two. Then adjust the last pass to compensate for the difference. Typically I can hit 0.0005" dimensional accuracy.

If you are pushing too hard on turning or drilling you will get some chatter or singing, so that is the nice feature of the VFD that you can adjust the speed on the fly. I find this is a significant factor when drilling and boring, so my MT3 drills, something like a 3/4" will be happiest at around 250 RPM, a 1/2 drill around 400-500 RPM, 1/4" around 800 RPM into steel with some lube and periodically clearing the chips.

Below are some chuck keys for the Bison I made a long time ago, I cut the square using a collet block on the mill and used a file to tweak the final fit. I relieved the back end to decrease the weight and added a small set screw that holds the T handle in place. I use a small magnetic in the tip of each key so they don not fall out when rotating the chuck. I set up a 0.0001" reading dial indicator in a QCTP holder which makes for very quick work of dialing down the TIR. I like the Starrett 25-511 or 25-611 series dial indicators because of the range (0.2") and resolution (0.0001"), sometimes they come up in good used condition for around $80 or new for a bit more. There are some inexpensive imports as an alternative, but I use one dial indicator and one test indicator for pretty much everything, it was worth buying once. When checking the TIR on the lathe I often use the JOG function for final reading, turning by hand can introduce more variation when turning the chuck.
https://www.ebay.com/itm/Brown-Shar...001-0-5-0-Rotating-Dial-Lug-Back/162914577775
https://www.ebay.com/itm/Starrett-25-611J-Dial-Indicator/292554013714

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Well made point on insert feed and speeds. I will add most lathes that are in home shops will not generate the SFM to optimize the insert. However that doesn’t mean you should not use them. I have posted many times on using CNMG 432 inserts on my lathes


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