Knurling Tool

Thanks to everyone, there a lot of good ideas and photos out there, I am sure I will be able to use some of them to build my project, when completed I will post a photo.
Regards
Nick
 
I use the scissor style knurling tool and I find that it takes a lot of pressure on the screw to make a good impression. To avoid that issue, I simply set the tool up so that it bears nicely top and bottom of the work, then retract the cross slide, tighten the tool and run the cross slide in to do my knurling. Then, I get tremendous pressure as the knurls approach center. The knurls don't actually have to reach the center line, and they work perfectly with very little strain on the lathe headstock or any other part of the lathe.
 
That's the proper way to use a scissor tool, Frank. The knurling pressure is on the scissor and very little on the cross slide screw. Otherwise it's the same as a bump knurler.
 
I use the scissor style knurling tool and I find that it takes a lot of pressure on the screw to make a good impression. To avoid that issue, I simply set the tool up so that it bears nicely top and bottom of the work, then retract the cross slide, tighten the tool and run the cross slide in to do my knurling. Then, I get tremendous pressure as the knurls approach center. The knurls don't actually have to reach the center line, and they work perfectly with very little strain on the lathe headstock or any other part of the lathe.

I guess I don't understand. This sounds like it's being used as a bump knurling tool, which does put tremendous load on the cross-slide screw. What am I missing?
 
You're missing that the adjustment it just smaller than the OD of the part being knurled. The pressure is through the pins the knurls ride on and the scissor pivots on. The rolls actually contact the work almost directly on center. The pressure is more like clamping the part than pushing into it.
 
You're missing that the adjustment it just smaller than the OD of the part being knurled. The pressure is through the pins the knurls ride on and the scissor pivots on. The rolls actually contact the work almost directly on center. The pressure is more like clamping the part than pushing into it.

Hi, Tony,

I understood what you've described; what I didn't understand was the "then, I get tremendous pressure as the knurls approach center". I guess my confusion was that I thought that he meant tremendous pressure on the cross-slide lead screw. Rereading it, I now realize he probably means the tremendous pressure between the knurls.

Thanks for the explanation...
 
Hi,

Since I just received my scissor-type knurling tool via UPS today, I wanted to make up a convenient spreadsheet of exact diameters for various nominal (starting) material diameters for various knurl pitches. I've attached it below; maybe it will be of help to someone. You should be able to copy the formulas to add other nominal material diameters and knurl pitches. Just be sure to place the knurl pitch in row 8 of any new columns, with the two-digit number of knurls per inch as the first two characters. The spreadsheet looks up the pitch from that row and uses it to make the calculations.

Here is the file: View attachment Knurl Diameters.xls
 
Here is my rendition of Chris Heapy's Clamp/straddle Knurler:

straddle knurler.jpg

They are not difficult to build but does require some thought and careful work. You can find the basic drawing here: http://www.astronomiainumbria.org/a...anica/easyweb.easynet.co.uk/_chrish/plans.htm Just adapt the size of the tool to your lathe and choose a mounting method. I suggest mounting directly to your carriage if you can. Knurling is a high-torque operation and all that torque is taken up by the tool; if it can move, it will. Mine is made to lock onto the Sherline carriage with a fairly large block; it is absolutely solid. Capacity is 0-2-1/2" so it works for me. This one is made from mild steel and uses 3/16" drill rod for the knurl axles so the cost, aside from the knurls themselves, was almost nothing but time.

One benefit of this design is that the arms are backed by a solid plate so there is very little deflection of the arms when axial running, which makes for a very consistent knurl.

If you haven't perused Chris' site before I suggest you take a look. It should be required reading for us hobby guys.

straddle knurler.jpg
 
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