# Generel guidelines for knurling



## ksor (Dec 18, 2007)

Do you have a link ?


Best regards
KSor, Denmark


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## Brass_Machine (Dec 18, 2007)

Ya know, I am interested in this too. We didn't cover knurling in the shop classes I took. Anyone want to do a tutorial?


Eric


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## kellswaterri (Dec 18, 2007)

Hello All,
a few links that may be of help...

http://www.jjjtrain.com/vms/cutting_tools_lathe/cutting_tools_lathe_04.html

http://www.metalworking.com

http://www.ezinearticles.com/?An-Introduction-toKnurling-Tool&id=771292

All the best for now,
              John.


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## tattoomike68 (Dec 18, 2007)

There are a few types and some are better than others. If I were to make a buy one I would go with the scissor type.

I have seen screw machines knurl long flimsy peices at high speeds with a guide bushing in the tailstock to act much like a center and the machine would use the tool at high speed. You can get away with that when the machine is blasting oil at 100+psi.

I have found that the more oil the better.

knurling and thread rolling are very simular and I can tell you that thread rolling is super fast with the best finnish making the best threads. It will make the fastest cnc look like its running in granny gear. Both operations are done with lots of oil.


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## mklotz (Dec 18, 2007)

Some general thoughts on the subject...

Buy a scissors type knurling tool. The extreme pressures involved when using a standard type knurling tool on a light lathe can play havoc with the spindle bearings.

Use the lowest spindle speed (backgear).

Use plenty of dark, sulphurated cutting oil. While it's true that knurling is an embossing rather than cutting process, knurling, especially in brass, will cause metal to flake off the parent stock. This needs to be flushed away to obtain a clean knurl pattern. Keep oil brush (and fingers and cloth wipers) well away from where the action is. (I have several acid brushes with beautifully knurled, very flat handles.) A squirt type oil can is advised for applying cutting oil.

If the knurls don't track perfectly when the tool is first applied, keep applying more pressure until they do track. When the knurls are forming to your satisfaction, move the tool to complete the knurling operation. Avoid making multiple passes with the tool if at all possible.

Newly made knurls can be somewhat uncomfortable to the fingers in any application where moderate manual pressure must be exerted on the knurled surface. After the knurling is completed, take a file and lightly break the sharp points for the comfort of the user.


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## Powder keg (Dec 18, 2007)

A guy I work with Knurled his 6" scale LOL:O)


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## Bogstandard (Dec 18, 2007)

I know that this might sound a bit offputting, but everyone has their own way of doing knurling. I have both the scissor type and the normal in from the side.
Now this is where the techniques and preferences differ, I don't like the scissor type, even though they say it is better for your machine, I tend to use the scissor type only on very small parts that can't take the side loads, and I run mine fairly fast. So asking people to do a write up might get a lot of different views to doing the job. Machinery comes into play, a big heavy machine will take the side strain, whereas a smaller machine really would need to use the scissor type.

Just type 'knurling' into google, and do a bit of site searching and you will find all the info you require, I did this when you put this post up, and what came up was very informative and surprising.

I will just tell you how I do mine.
I touch the knurl onto the job and apply a bit of pressure until I can see an impression being formed.
Then I bring the knurl off and look at the impression and see if it is equal impression all the way across. If not I readjust the tool in the correct direction, and try again. It will be only a tiny adjustment usually.
Then bring the tool onto the job, and put a feed in of about 5 thou, and plenty of oil onto the job, as Marv said, this is an embossing process, but usually some fine chips are formed, I use a toothbrush (the wife complains a bit at the black bristles, but what the hell) to clean away the swarf. Let the cut run its course for a while, then put another cut on, oiling and cleaning as required until you reach the finished stage.
At that stage, I usually either take a small skim off the surface or dress it down with a stone, just to take the sharp edges off (but not if using it to expand the size, more of that later). I also usually put a small chamfer on the outer edges of the knurled face (if space allows), it just finishes the job off.
There are basically two types of knurl that we use, one is a diamond pattern and the other is a straight knurl, there are many other types used for different jobs and decorations but I will concentrate on these two.
For me, I tend to use the diamond pattern where I have to grip something (like a scriber) and the straight one for turning or tightening something (an adjusting wheel or a locking nut). But the choice would be yours, there are no hard and fast rules, do what you want.
There is another side to knurling, and that is getting yourself out of the s**t.
Say you bored a hole in a flywheel slightly too large (this is just a quick example), what you can do is knurl the area of shaft it sits on and this will expand the shaft by up to 10 thou (depends how deep you go), so allowing you to get a tighter fit. This can also be used to put on an assembly where you want a nice tight fit, rather than having to resort to adhesives to lock things together.

Here are a couple of pics of the knurling tools that I use.














Hope this helps


John


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## Cedge (Dec 19, 2007)

Anyone tried making "millgrain" wheels? I've seen John moran's rope knurl and am considering ways to recreate a couple of these designs in a larger version for lathe use. I missed out on a full set of old fancy embossing and knurl wheels right after I bought my machines. Had I know they were so rare, I'd have fought harder to win them. 

Steve 

http://www.shorinternational.com/MillgrainBeader.htm#Lathe Millgrains


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## Bogstandard (Dec 19, 2007)

Very nice decorative stuff there Steve.

But the prices, wow!

Definitely a reason to try to make your own.

John


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## Powder keg (Dec 19, 2007)

Here is a good link on making a "rope knurl" He has a lot of other great tips also:O) http://www.frets.com/FRETSPages/Machining/Projects/RopeKnurl/ropeknurl.html

Wes


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## Bogstandard (Dec 19, 2007)

Great link there Wes, just the type of thing we are after.
Short and sweet and easily understood by all, nothing too technical otherwise my brain starts to hurt.

John


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## Powder keg (Dec 19, 2007)

Here's a nother on knurling http://www.proshoppublishing.com/articles.html


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