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View Full Version : knurling without oil???



Alistair Hosie
03-20-2007, 02:38 PM
what is it about knurling.I have both read that using oil is ok and not ok what is best since it is a compression of the metal as oposed to a removal of the metal how can oil help ??Alistair

Rusty Marlin
03-20-2007, 03:16 PM
I use oil at home, and in production we use oil. The oil is to help the steel form in the knurling tool and keeps it from sticking and galling, flaking off the surface, and keeps the temp down (a little). Basically the oil is used for everything that its used for in cutting; it improves the process.
I've never knurled Aluminum, but I'd use WD-40 just like when cutting.
I have no idea why one wouldn't use oil in all honesty. :confused:

CCWKen
03-20-2007, 03:24 PM
The only parts I oil are the pins. Many folks use oil or flood coolant because their wheels are cutting as they slide into a previously made grove. Many claim that hard pressure is all that's needed and the knurls will follow themselves. This assumption is incorrect as a stock circumference that falls between a multiple of the knurls pitch will produce double (or more) tracking lines.

A good knurling setup will not produce chips because, as you say, the knurls are formed by displacing metal. The knurls aren't designed to cut and will last longer if they aren't forced to cut by sliding into a grove. That's where the chips are coming from. ;)

Alistair Hosie
03-20-2007, 03:26 PM
What I read was that the oil was useless unless removing some material and as this does not remove material ,but compresses it, it would only hinder the process. Others seem to talk about using it. so I am confused but in the meantime I'll take your advice Rusty and keep using it thanks Alistair

DR
03-20-2007, 03:58 PM
The company we buy our knurl wheels from has always told us doing the process dry is best.

Since our knurling is mostly relatively high production on a CNC lathe we program the machine to give a squirt of coolant onto the knurl head for lubrication of the knurl wheel axles.

BTW, all knurling should be done in a single pass. Those tools sold by Armstrong and others requiring multiple passes to form the knurl by side pressure are the work of the devil. Get a scissor type or other type with opposed knurl wheels and enjoy good looking knurls everytime.

matador
03-20-2007, 06:13 PM
I have always used Tapmatic when knurling,but i only have a single wheel tool.I line the wheel up to cut a first pass,and go as deep as i want to,before running along the work.
The only thing that bothers me,is that the knurl feels quite"sharp".Does that mean i cut too deep,or am i supposed to run a file over it before use?

Mcostello
03-20-2007, 09:27 PM
You can just lightly run a file over the knurls if you want to. Want to find out how much play is in your lathe? Just dab an acid brush between the knurls and the work, you will be amazed at what happens, sometimes very quickly. Don't ask how I know.........

BadDog
03-20-2007, 09:54 PM
Strange, I was told to always use high sulfer dark oil, and I do. Applied with a flux brush it seems to work well, just don't let it get caught! :D

wierdscience
03-20-2007, 11:02 PM
I've got an old drip oiler I hang over the knurl,oiling is one less thing I have to do while knurling that way.

Evan
03-20-2007, 11:20 PM
BTW, all knurling should be done in a single pass. Those tools sold by Armstrong and others requiring multiple passes to form the knurl by side pressure are the work of the devil.

I have pretty good luck with that type of tool. As my lathe has plain bearings I haven't worried about the side pressure on the spindle. When knurling aluminum I use a continuous spray of WD40 to flush the work during the pass and clean it with air between passes. It usually comes out pretty well.

http://vts.bc.ca/pics/lsk3.jpg

Your Old Dog
03-21-2007, 06:40 AM
I would think oil would help in that it is squished out as the roll progresses and carries any chips with it at the same time offering a fine layer of oil to the knurlers fine diamond tips. I can't see how oil can cause any harm, it's not at all like dropping a piece of sheet steal onto another piece that is coated with oil. The rolling action will remove what oil is not needed so there should be no compressive tendency. But...........that's just me talken!

kap pullen
03-21-2007, 07:29 AM
what is it about knurling.I have both read that using oil is ok and not ok what is best since it is a compression of the metal as oposed to a removal of the metal how can oil help ??Alistair

Alistair,
I'm curious what you are reading, and where.
Lots of experts out there, maybe we can all learn something!
Kap

Alistair Hosie
03-21-2007, 08:55 AM
I can't remember where I saw it but I'll try to find the portion about no oil Alistair