PDA

View Full Version : Knurling question revisited



hwingo
07-17-2010, 08:52 AM
My question is as follows. When knurling a piece (perhaps as long as 4 to 6 inches) and travel distance is reached, should lathe-travel be disengaged, the knurling tool backed away from the piece, and the saddle moved back into position for a second pass, OR should travel be left engaged while the tool remains in contact with the piece, and the motor reversed so "tracking" is not disrupted as the tool passes back to the starting position?:confused:

Harold

Rusty Marlin
07-17-2010, 09:13 AM
I use a scissors knurls and if I try to reverse feed the forces cause the knurling tool to cock on its axle and it totally mucks up a perfectly good knurl.
Sooo.....
If the work requires and extra pass I kill the feed and and the spindle at the same time, open the knurling tool and return the carriage back to the start. I then wire brush the knurling on the work and the wheels to remove any fines. With the spindle still off, carefully tighten the knurling tool while hand guiding the wheels back into the knurling so they track correctly, then turn on the spindle, tighten the knurl whatever feels right to get good points and engage the feed.

hwingo
07-17-2010, 03:57 PM
Thanks for your reply. I will give your method a try and see how it goes.

Harold

Carld
07-17-2010, 04:10 PM
That's interesting, I haven't used a scissors type knurler but with my push type I can manually feed it both ways or hand feed it both ways. Most the time I hand feed the knurler back and forth over the work.

MichaelP
07-17-2010, 04:41 PM
That's interesting, I haven't used a scissors type knurler but with my push type I can manually feed it both ways or hand feed it both ways. Most the time I hand feed the knurler back and forth over the work.
That's exactly how I was taught: move the carriage back and forth manually and do not lose contact with the work piece (do not move the knurling wheels beyond the end of the shaft being knurled). Advance the cross slide in to increase depth of the knurls and move the carriage back and forth again. Repeat as needed. Use lubrication.

Davidhcnc
07-17-2010, 05:15 PM
This is how I do knurls. This works every time regardless of diameters.

My knurling tool

http://homepage.ntlworld.com/david.hull35/CNC/knurl%20001.jpg

Touch on to the work like this and zero the dial.

http://homepage.ntlworld.com/david.hull35/CNC/knurl%20002.jpg

Start up and fed in until a good pattern is achieved.

http://homepage.ntlworld.com/david.hull35/CNC/knurl%20003.jpg

Read the dial. This is 1.8mm. Now we know where we are going. Notice the dodgy knurling on the dial!

http://homepage.ntlworld.com/david.hull35/CNC/knurl%20004.jpg

Davidhcnc
07-17-2010, 05:16 PM
Approach the knurling as screwcutting, lets say 5 passes to arrive at the final depth. First pass, withdraw and reposition for the next pass..you know the drill.
The knurls are registered each pass by the prestarted band.

After first pass

http://homepage.ntlworld.com/david.hull35/CNC/knurl%20006.jpg

Completed.

http://homepage.ntlworld.com/david.hull35/CNC/knurl%20008.jpg

Mystery steel 1" dia, speed maybe 300rpm and feed whatever you cut at, coolant, if you have the luxury or oil.

Toolguy
07-17-2010, 05:21 PM
The push type or bump style knurlers are really hard on the cross slide lead screw and especially the nut. Good way to wear them out If you do much knurling. The scissor or plier type knurling tools take all the load and are easy on the lead screw and nut.

clutch
07-17-2010, 05:32 PM
I learned Aloris makes a sweet opposed type knurler. Assuming no unexpected expenses come up by December, it will be my Christmas present to me. Aloris is kind of spendy so something just as good would be nice to know about. I'm using a BXA post.

Clutch

Lew Hartswick
07-17-2010, 06:22 PM
At school the students are knurling Aluminum and we always "try" to
do it in one pass BUT again ALWAYS tell them to just stop at the end
of the pass and DON"T touch anything. After examining the knurl, if it
insufficient just reverse the spindle and tweek the tension on the scissor.
So I guess it's one of those " It depends " things again. :-)
...lew...

Mcgyver
07-17-2010, 06:40 PM
At school the students are knurling Aluminum and we always "try" to
do it in one pass BUT again ALWAYS tell them to just stop at the end
of the pass and DON"T touch anything. After examining the knurl, if it
insufficient just reverse the spindle and tweek the tension on the scissor.
So I guess it's one of those " It depends " things again. :-)
...lew...

there was a guy here a few years who claimed to knurl steel in one pass, I believe with a standard pressure knurler.....other than the bold claim he wouldn't come forth with details......if you're still around oh mystery super knurler please tell us how you do it

saltmine
07-17-2010, 06:53 PM
Geez! The radial loading on the spindle and the carriage must be hideous, especially with a form knurler.

That's why I'm building Michael Ward's "cut knurler". I've already built a prototype and am seriously impressed with the results. I can cut a nice, well defined knurl in O-1 drill rod with one pass, using the cut knurler....I don't think I could even make an impression in O-1 with my scissors knurl.

If I make a pass, and decide it's not deep enough, I stop the machine, reverse the lead screw, and turn it back on and let the knurler "walk" back in it's own tracks. Properly set up, a cut knurler usually makes a beautiful knurl in one pass, regardless of what the metal is.

Mcgyver
07-17-2010, 09:47 PM
Geez! The radial loading on the spindle and the carriage must be hideous, especially with a form knurler.
.

yeah i hear you, I wasn't going to do it, just didn't like that it was left unexplained