I know there are a lot of threads about parting tools, how to use them,etc. i have a HF 7x12 mini lathe that uses 5/8 tools. I purchased a cheap set of tools from HF which included a parting tool. I am working on a 1" diameter aluminum rod by the way. When i tried to use it there was quite a bit of chatter when just starting. It did a very shallow cut then would not cut any more material. I checked its position relative to the live center and it appeared to be at the right height. The blade on this tool is approx. 1/8 wide. I am new to this lathe and have not used one for years just for some back ground information on my knowledge on these. Can anyone recommend a parting tool that will fit this lathe i can purchase? Based on some reading thinner seems to be better i think. Any help would be appreciated.
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Parting tool selection
- Thread starter RB72
- Start date
"Easy" parting is dependent on several critical factors - all of which need to be correct. First of all, get a parting tool holder like the one sold at LMS. See link below:
http://littlemachineshop.com/products/product_view.php?ProductID=1551&category=
Then, outfit it with a thin parting tool - like the ones LMS sells (LMS, btw, is not the only place you can purchase these tools, but it was quickest link for me to find).
The parting tool itself should stick out past the holder by the smallest length that will allow you to part the workpiece. It must be perpendicular to the workpiece (use a small machinist's square to verify and rotate the holding block on its stud, until it is, and then lock it down, and measure again). The height of the tool is critical - if too high then the parting tool rubs on the work somewhere below the cutting edge. If too low, the work rubs behind the cutting edge. I use a cheap plastic level, sold by many suppliers. It has a V cutout which you lay against the workpiece, and a ledge that you lay on the tool edge. Having previously leveled the lathe, this will then indicate that the cutting edge is right dead on a diameter of the work piece. Many machinists say that the best thing to do with the smaller lathes is to then shim the parting tool holder just a hair high, as the work will pull the cutting edge down when you engage it. A Carriage lock is very helpful in keeping everything stable while you part. Now, using your choice of cutting lubricant fluid, advance the tool into the work. It should cut without chatter, and "peel" off a thread of the workpiece. Advance the cutter slowly, keeping the lathe at a slow to moderate speed, and the fluid applied. If everything is adjusted properly, and locked down tight, you should be able to part as easily as you do any other cutting operation.
Two other thoughts that may be helpful. The second thing i built with my new lathe and mill (an X2 from Harbor Freight) was a quick release tool holder and some dovetailed sliding blocks to hold the cutters. This allows you to very quickly drop the current cutting tool into place, and once adjusted with the little thumbscrew for height, the tool height will stay correct until you move the tool in the block for some reason. The fourth or fifth thing i built for my lathe was a carriage lock - a lever-operated type that draws an aluminum "shoe" up under the ways. Between these two accessories, setting up the lathe for work, quickly and without much fuss, becomes much easier. The carriage lock contributes a lot to the overall stability of the carriage, especially during parting. So, when i need to make tooling or modify a tool i bought for my other hobby, woodworking, i can go into the machine room, and get set up to make the part very quickly.
good luck, and have fun.
Bert
http://littlemachineshop.com/products/product_view.php?ProductID=1551&category=
Then, outfit it with a thin parting tool - like the ones LMS sells (LMS, btw, is not the only place you can purchase these tools, but it was quickest link for me to find).
The parting tool itself should stick out past the holder by the smallest length that will allow you to part the workpiece. It must be perpendicular to the workpiece (use a small machinist's square to verify and rotate the holding block on its stud, until it is, and then lock it down, and measure again). The height of the tool is critical - if too high then the parting tool rubs on the work somewhere below the cutting edge. If too low, the work rubs behind the cutting edge. I use a cheap plastic level, sold by many suppliers. It has a V cutout which you lay against the workpiece, and a ledge that you lay on the tool edge. Having previously leveled the lathe, this will then indicate that the cutting edge is right dead on a diameter of the work piece. Many machinists say that the best thing to do with the smaller lathes is to then shim the parting tool holder just a hair high, as the work will pull the cutting edge down when you engage it. A Carriage lock is very helpful in keeping everything stable while you part. Now, using your choice of cutting lubricant fluid, advance the tool into the work. It should cut without chatter, and "peel" off a thread of the workpiece. Advance the cutter slowly, keeping the lathe at a slow to moderate speed, and the fluid applied. If everything is adjusted properly, and locked down tight, you should be able to part as easily as you do any other cutting operation.
Two other thoughts that may be helpful. The second thing i built with my new lathe and mill (an X2 from Harbor Freight) was a quick release tool holder and some dovetailed sliding blocks to hold the cutters. This allows you to very quickly drop the current cutting tool into place, and once adjusted with the little thumbscrew for height, the tool height will stay correct until you move the tool in the block for some reason. The fourth or fifth thing i built for my lathe was a carriage lock - a lever-operated type that draws an aluminum "shoe" up under the ways. Between these two accessories, setting up the lathe for work, quickly and without much fuss, becomes much easier. The carriage lock contributes a lot to the overall stability of the carriage, especially during parting. So, when i need to make tooling or modify a tool i bought for my other hobby, woodworking, i can go into the machine room, and get set up to make the part very quickly.
good luck, and have fun.
Bert
- Joined
- Jan 22, 2013
- Messages
- 56
There are also many other factors as to why you are getting chatter. I have a 7X14 and had to go through the learning curve for parting on these machines. First is you need to check that all your gibs are tight. If the tool can move up and down at all it will chatter. This is something that you may not be able to feel so you need to actually check the tightness of the carriage gibs and the compound slide. Keep the tool extension as short as possible, less leverage and more rigidity that way. Next is lube, you can turn most metals dry but when parting, lube is a must. For Al the most common is WD40 or kerosene. One more way I found to part easier on the 7X14 is to invert the blade in the holder if possible and cut with the lathe running in reverse. This way if the tool grabs it pulls the blade out of the cut rather than pushing it in to the material. Make sure the cutter is at 90 degrees to the material. Easy way to do this is to use a parallel or any thing with parallel edges and push it against the face of the chuck then tighten. I am sure many people have some tricks but these are the ones I use the most.
BTW - and this is off topic to this question, but i think it's valuable to know - if you bought a set of the HF carbide tipped cutting tools, put them aside, go back to the HF store and buy a couple of steel tool blanks. Read through any of the many references that explain how to shape the tool. Get yourself into the spirit of understanding how the tool cuts.
After using your home made tools for a year or so, during which year you are saving your allowance (your sig other does give you an allowance, right?) buy a set of tool holders which take replaceable carbide or steel cutters. Again, i bought from LMS, but it is far from the only place that sells these. Each cutter is perfectly shaped, and attaches to the holder with a little torx screw. They work nicely. You can also buy steel cutters if you are so inclined.
The advantage of following this route is that from your experience grinding tools, you will know how the tools need to be shaped. And, when you finally purchase the set of holders, you will have the convenience of well- shaped cutting tools. Add the quick-change tool post and you are really good to go and get to work.
Of course, you could make a hobby of modifying and improving your lathe, but i sense from your original question about parting, that you would like to make stuff with it.
b
After using your home made tools for a year or so, during which year you are saving your allowance (your sig other does give you an allowance, right?) buy a set of tool holders which take replaceable carbide or steel cutters. Again, i bought from LMS, but it is far from the only place that sells these. Each cutter is perfectly shaped, and attaches to the holder with a little torx screw. They work nicely. You can also buy steel cutters if you are so inclined.
The advantage of following this route is that from your experience grinding tools, you will know how the tools need to be shaped. And, when you finally purchase the set of holders, you will have the convenience of well- shaped cutting tools. Add the quick-change tool post and you are really good to go and get to work.
Of course, you could make a hobby of modifying and improving your lathe, but i sense from your original question about parting, that you would like to make stuff with it.
b
I'm not familiar with that particular lathe, but just as a shot-in-the-dark -- is the parting blade pretty close to horizontal ? And is there some relief ground into the leading edge ?
You need some relief under the cutting edge (I think HSS is supposed to be +/- 7°,but there are plenty of wiser heads on this forum to correct that), and if you have the front of the tool too high, the area below the cutting edge might be rubbing on the workpiece.
You need some relief under the cutting edge (I think HSS is supposed to be +/- 7°,but there are plenty of wiser heads on this forum to correct that), and if you have the front of the tool too high, the area below the cutting edge might be rubbing on the workpiece.
This is all great information. I am shopping for the new holder and blade. As everyone has said thinner is better. I am going to the LMS site as a starting point. Also I did not use any lube when I tried this. Will check the height of the blade again and will come back to this thread once the new blade shows up to make sure I follow the right procedure. Oh and squaring the blade up to the chuck is a great idea.
I am using 1" al now but for steel use the same parting blade or should it be wider?
Bert how do you like the HF mini mill you mentioned? Next machine on my list.
thanks all
I am using 1" al now but for steel use the same parting blade or should it be wider?
Bert how do you like the HF mini mill you mentioned? Next machine on my list.
thanks all
The mill is fine if you are just trying to make stuff. If you are a fanatic about rigidity, slop in the lead screws, and so on, you either need to join one of the forums dedicated to making a better mill out of what you buy, or spend more and buy a different mill. For me, it's another tool is all. I trammed it a while back, bought a nice mill vise, and a set of hold-downs from Travers tools. I also added an optical (glass scales) DRO on all three axes. And, i fixed a squealing bearing on the X-axis. Other than those fixups, and adjusting the gibs, cleaning and lubing it, i have spent little time making the sow's ear into a silk purse. But I have made a bunch of tools and tool accessories that I use in woodworking (I have turned to luthiery as I can no longer heft large pieces of rough lumber and make heavy furniture) - most recently i bought a Horrid Fright laminate trimmer on sale and with a 20% coupon, for about $23. I concluded that the basic motor and base were sound, but the trimming guide was pretty crappy. At first i used the mill to establish a reference flat surface on one of the critical sliding pieces, and also made a larger guide roller. In the end, though, i decided after using it on one guitar, that i needed to make the entire guide again (actually i re-used one part of the original) so that i would be able to rout channels for edge bindings on a Jumbo acoustic guitar I am building. Around here there is a company that sells surplus aluminum and steel (one of their branches about 75 miles from here also carries brass and bronze I am told) bar and rod, and a couple of years ago i spent my allowance on some Al bar. (I also scavenged some nice steel rod from a nearby computer store that had some trash printers). It was from the aluminum bar, that i made the guide accessory. I also use a HF 14-inch woodworking bandsaw, with a metal-cutting bimetal blade to cut stock into workable sized hunks. And woodworking, of course.
So, bottom line - only you know yourself well enough to know whether your goal is making a hobby out of fixing a mill, or using a mill to make stuff. Either way, it's worth the money, imho especially with a coupon, and if your local store has one in stock.
b
BTW - to answer your question about the parting off blade - use the same blade. And don't forget to spend two or three bucks on the level - i forget where i bought mine, but they are quite common and vital to getting set up properly. I think i described it in my first reply. I just looked in the LMS catalog, and I don't see it. Here's a link to Travers - they have a few types, much more expensive than the one i bought, but from the picture you can get the idea of what you are looking for (there is a zoom magnifier so you can get a closer look):
http://www.travers.com/344564-99-008-193?Category=UserSearch=level lathe
The one I bought from one of the hobby machine suppliers is much thinner - just a disk of plastic with a pie-wedge cut out of the circumference, and a tail that rests on the cutter. YOu have to level the entire lathe first, of course, before using one of these.
And, while you are ordering a parting blade and holder, don't forget to get a 3 or 4-inch machinist's square - I bought a Starett 4-inch at a flea market, soaked it in Evaporust, rinsed it, painted the casting, polished the reference surfaces on a lapping plate, and use it frequently in the machine room as well as for woodworking. I paid less than $5 for it. But, any true square will work to align the parting blade if you can fit it in between the work and the tool.
Above all, have fun.
bert