i have the normal hss parting tool for my excell tool holder. but i am wondering if there is a better tool to use. the hss seems to only work on aluminum, but i will be machining a lot of stainless and regular steel which the hss does not like to work on at all. If you guys could post up some different links to different tooling i would appreciate it. also if you have some tips on it that would be great. im new so i take absolutely no offense to any tips no matter how elementary you think they are. ive never been taught to run a lathe, just played around on them at school and at buddies shops.
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parting question
- Thread starter dcheff
- Start date
I use a normal parting tool in a QCTP. I got lucky the first time I used it and it cut cleanly. Then I messed up and adjusted the height after I mis-sharpened which was a big mistake. It just got real hot and started smoking. It needs to be JUST RIGHT. Not too high, not too low. And the front is slightly pointed, not straight. Sherline has a good description of how to sharpen it here:
http://www.sherline.com/3002inst.htm
Once I resharpened like it says and used the ruler trick to make sure it was perfectly centered top-bottom it went back to cutting cleanly. They recommend slowing down the lathe speed, but I found that when it was set up perfectly and the bit was sharp that I could go as fast as I wanted and it still cut cleanly.
http://www.sherline.com/3002inst.htm
Once I resharpened like it says and used the ruler trick to make sure it was perfectly centered top-bottom it went back to cutting cleanly. They recommend slowing down the lathe speed, but I found that when it was set up perfectly and the bit was sharp that I could go as fast as I wanted and it still cut cleanly.
Yes tool height is the most important item after sharpness. Parting off has been a scray thing at times, what with bad chatter, jamming in the cut, broken blade and on and on.
I too have used HSS in a regular holder and never confident about the cut. Later on I had the opportunity to use an insert holder and cutter and WOW, the difference! High speed cutoff like in the videos is possible if the machine is stiff enough. I have moved from an Atlas 10F to a more modern Jet clone BDB-1340 like machine and it is a whole new world. No chatter and better cutting speeds and naturally a better finish.
Pierre
I too have used HSS in a regular holder and never confident about the cut. Later on I had the opportunity to use an insert holder and cutter and WOW, the difference! High speed cutoff like in the videos is possible if the machine is stiff enough. I have moved from an Atlas 10F to a more modern Jet clone BDB-1340 like machine and it is a whole new world. No chatter and better cutting speeds and naturally a better finish.
Pierre
Im still using the HSS tooling, and seem to have good results. If your new to parting, you should be aware of a few things. The tool should be on centre, thats typical. The tool should also be choked up to the tool holder so the min amount is sticking out. When setting up, make sure the cutting tool is not angled to the work. You can use a 123 block, and hold it up to the chuck, and wheel the cariage up to check for this.
When cutting , I would recomend a slow speed, and lots of oil. On tough materials, if you use flood coolant, it helps to keep the material, and heat from building up. To much heat, and you can have it grab the tool cutter, and break it. I some times will retract the tool, and check to work piece, and tool for excessive heat. If need be, a cool down period is in order.
Check your gibs before doing any parting. Loose gib ajustment will lead to trouble. The axis your not using should be locked down, and the compound checked, and locked if it has a lock. I would recomend feeding in by hand at first to get a feel for the cutting action. If its cutting well, and your keeping the oil flowing you should be fine.
If your feeling your using excess pressure to get the cut started, chances are the tool isnt sharp. At that point, your best to have a look at that, or if you push it to hard, you may dig in, and again snap the tool cutter.
Parting off under power is somthing I would not reccomend you doing till you get used to the parting process. Small lathes that arnt very ridgid can be a problem parting under power. Big , heavy ridgid machines are more forgiving. The speeds and feeds will need to be tested to find what works on your machine.
Keep the chips coming off cleanly, keep the heat down, and a sharp tool is allways better than a dull one.
When cutting , I would recomend a slow speed, and lots of oil. On tough materials, if you use flood coolant, it helps to keep the material, and heat from building up. To much heat, and you can have it grab the tool cutter, and break it. I some times will retract the tool, and check to work piece, and tool for excessive heat. If need be, a cool down period is in order.
Check your gibs before doing any parting. Loose gib ajustment will lead to trouble. The axis your not using should be locked down, and the compound checked, and locked if it has a lock. I would recomend feeding in by hand at first to get a feel for the cutting action. If its cutting well, and your keeping the oil flowing you should be fine.
If your feeling your using excess pressure to get the cut started, chances are the tool isnt sharp. At that point, your best to have a look at that, or if you push it to hard, you may dig in, and again snap the tool cutter.
Parting off under power is somthing I would not reccomend you doing till you get used to the parting process. Small lathes that arnt very ridgid can be a problem parting under power. Big , heavy ridgid machines are more forgiving. The speeds and feeds will need to be tested to find what works on your machine.
Keep the chips coming off cleanly, keep the heat down, and a sharp tool is allways better than a dull one.
I've done plenty of parting on SS using HSS and have had very good results. Latest example of HSS/SS parting -
I just got set up with a parting blade using carbide inserts. I haven't tried it on SS yet but it did a great job on brass -
-Ron
I just got set up with a parting blade using carbide inserts. I haven't tried it on SS yet but it did a great job on brass -
-Ron
T
Tom Griffin
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High speed steel works very well on carbon and stainless steels, you just need to calculate the proper rpm based on the type of material you are cutting and its diameter. Basically that's four times the cutting speed of the material being cut, divided by the diameter of the work. For example, if you are turning a 2" diameter bar of 303 stainless, the rpm would be 4 X 80(the cutting speed of 303 stainless)/2, or 160 rpm.
There are a lot of factors that need to be right for parting. The tool needs to be ground sharp and square on the end, it needs to be on center vertically and dead square to the work. This is very important. Use The face of the chuck to square it up or indicate it, but it absolutely must be square. Tool overhang needs to be at a minimum for max rigidity and you need to use either flood coolant or a steady supply of sulphur based cutting oil. I generally run parting tools about half the speed of turning tools.
Tom
There are a lot of factors that need to be right for parting. The tool needs to be ground sharp and square on the end, it needs to be on center vertically and dead square to the work. This is very important. Use The face of the chuck to square it up or indicate it, but it absolutely must be square. Tool overhang needs to be at a minimum for max rigidity and you need to use either flood coolant or a steady supply of sulphur based cutting oil. I generally run parting tools about half the speed of turning tools.
Tom
Not to reiterate but I mostly work with brass and the odd stainless I have found slow with lots of fluid works best so long as tool height is good and tool is sharp.
Not to go off topic but looking at the pic of brass above the tool height might be off, when I set my qctp I go for the same finish as facing, no nub. That said that's how I set it but I mainly work on brass.
Not to go off topic but looking at the pic of brass above the tool height might be off, when I set my qctp I go for the same finish as facing, no nub. That said that's how I set it but I mainly work on brass.
squaring the holder by the chuck is one thing i figured out on my own, was a proud moment lol. i also ordered one of those little tools to help align the cutting tool to the center of your work so maybe that will help. i have noticed if i play with it it will sometimes part better than others, this might also be due to the fact that i still have a standard grinding wheel and not a good wheel for sharpening hss.
other than that i just picked up an oil can for lubing the machine and for cutting applications, spray oil isnt nearly thick enough i dont think. My buddies dad is going to stop over soon and teach me about using the lathe, he is one of those machinists who knows everything and can do everything perfectly, probably the smartest man i have ever met. i think he is just happy that i have my own lathe and dont have to use his anymore haha.
other than that i just picked up an oil can for lubing the machine and for cutting applications, spray oil isnt nearly thick enough i dont think. My buddies dad is going to stop over soon and teach me about using the lathe, he is one of those machinists who knows everything and can do everything perfectly, probably the smartest man i have ever met. i think he is just happy that i have my own lathe and dont have to use his anymore haha.
Hello Dcheff
If You feel lust to part with a lot of money for getting get rid off Parting Off Fear ,there is a describtion of an Iscar system that Works well for me.
Am no god linking and to old to learn but if You go to a contribution from me in a thread called Trouble with parting off You are at the gate of troublefree parting but it will cost You
Enjoy the pictures and I will never be back for HSS blades in QCTP holders.
Farfar aka Niels
If You feel lust to part with a lot of money for getting get rid off Parting Off Fear ,there is a describtion of an Iscar system that Works well for me.
Am no god linking and to old to learn but if You go to a contribution from me in a thread called Trouble with parting off You are at the gate of troublefree parting but it will cost You
Enjoy the pictures and I will never be back for HSS blades in QCTP holders.
Farfar aka Niels
T
Tom Griffin
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Register Today
Yes, rigidity and squaring up the tool is probably the most important part of set-up, with lubrication running a close second. If you don't have flood coolant on your lathe, get some cutting oil and brush it on. You need the smelly, sulphur based stuff, motor oil and light oils like WD-40 will not work.
Good job on discovering the alignment trick. :thumbsup:
Tom