Need knuling tools for mini lathe
Does anyone have a location in the U.S. that I can find knurling tools for a mini lathe..I have a Cummings
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If u have [size=150]THIS[/size] tool, it’s squirrely as hell but works OK (on 6061 Al anyway). 😯
I strongly suggest that you practice on some scrap first!
thanks BB i will give it a go….i thought it was something like threading and the rollers would have to line up somehow every time
Cygnus,
As you said, it does not matter. The cut on the knurls determine how coarse or fine the knurl is. feeding with a 20 pitch or a 40 pitch feed rate is not going to make a difference in the coarseness of the knurl.
There is no “overlap” once you start the knurling process, do not remove the knurling tool from the part. That is about the only time you can “mess up” a knurl. If you move the tool away from the part, you MUST reingage it slowly enough for the knurling wheels to “mesh” with the knurl that has already been cut.
I think if you follow the instructions I wrote in the thread above, you will not have any problems. Feed rate is not important, as lone as it is not too fast. Starting out, simply feed the carriage by hand, a little ( .010 -.020)at a time, alowing 5 – 6 revolutions of the spindle as you go when you get to the end of your pass, simply start feeding in the other direction you will get the hang of it.
You simply have to see it work. And you cant do that untill you just jump in there. As long as the work is supported and everything is tight it will be fine. Keep it lubed.
say i want to knurl a lengt of roundbar 6″ long
i would engage the gears and the half nut to let it move along the bar….but how do i keep it from overlapping the pattern or maybe it doesnt matter if it overlaps ?
Im not sure I understand what you are asking Cygnus. The speed for knurling? Changing the speed doesnt change the ridges/knurls per inch. That is a function of the knurling wheels.
what kind of gearing should us with mini lathes use is a 20tpi what we are aiming for or ?
Knurling is usefull for other than looks and grip. If you have round pieces that fit loosely, you can knurl them slighty ( which “moves” the material making the diameter grow) and then turn or polish It down to fit properly.
I have even mounted a knurling roll on a spindle and used it in a boring head to “fix” a loose I.D. on the milling machine.
feeds & speeds, It is kind of see how it does thing. A 1.25 inch piece of material, ( reguardless of type ) I would start at around 300 rpm.
Make sure that knurls are square with your workpiece at all times, feeding too rapidle will move them and effect the quality of your knurl.
It is important that everything is clean, you need to use clean cutting oil
no WD-40, you need thick cutting oil, engine oil is OK (better than anything thin). As long it is not contaminated. Anything getting in the knurling rolls will get pressed into the material.
Always support the end with a center. If you are knurling tubing, make a plug to fit the end and center drill it to support your stock. Unless you have teh “sissor” type of knurling tool there is alot of lateral force on your part.
Start on either end. Start the spindle and slowly crank the knurling tool into the part. Think of it as a tubing cutter, you can’t cut it in one revolution of the part.
Once you engage the part with the rolls, do not remove them. It is possible to do this ( pull them back ) but when you move them back forward, you must alow them to “mesh with what you have already formed.
Look, feel to see how deep they are, you can stop the spindle at any time
to see this if you want, just remember not to move the rolls away from the part.
If it is a medium to fine knurl, you can cut it in one pass, a corser knurl you might want to make more than one pass. don’t be afraid to make two or three passes on deeper knurls, they will look better and not put so much pressure of your tooling. Keep plenty of oil on the knurls.
If you are starting on the right hand end of the part, ( I usually do )
you can simply start moving the cariage to the left by hand allowing a few revolutions of the spindle as you go to allow the knurl to form.
If you have power feed, you can turn it at about .010 – .020 thou. per rev.
when you reach the end, if you want to make another pass, simply reverse the spindle and feed direction. Hobby stuff, I always feed by hand.
Remember that these “Form” they do not cut. Always support the end with a center. If you are knurling tubing, make a plug to fit the end and center drill it to support your stock. Unless you have teh “sissor” type of knurling tool there is alot of lateral force on your part.
If you can, never knurl completly to the end of your part, it will “roll” the edge over.
Keep plenty of clean oil on it and have fun. just take it slow at first untill you see what it is like.
It is not difficult, just have to jump in there and try it. (maybe on a piece of scrap first)
Hope this helps
I can try to clarify if needed.
i got the large one they sell…havent used it yet….doesnt come with any kind of manual, nor does it tell at what kind of feed speed to use to get the results that will look good.
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Martin777
That tool is pretty weak looking, it would take several passes to get a decent knurl with that. But that doesnt mean you cant get a quality knurl. Take several passes, right to left, left to right very gradually increasing the pressure on each pass to keep the lateral forces low. Small tools require slower feed rates. This might help to control the
“squirrellyness factor”