A Straddle Knurler for the Sherline Lathe

[Grinderman]

Thanks, that kind of what I was thinking also but have seen similar knobs made both ways.

 

[mickri]

Mikey
I have decided to add your knurler to my project list. As is my normal practice I did a drawing of the knurler body and a holder for the knurler. I did not draw the arms or the adjusting screw. Material that I have on hand is 2x1.25 1018 flat bar. I am using all of your dimensions. I would mill out the slots for the arms. Can you see anything that I have missed? Suggestions?

 

[mikey]

Material that I have on hand is 2x1.25 1018 flat bar. I am using all of your dimensions. I would mill out the slots for the arms. Can you see anything that I have missed? Suggestions?

Am I correct in understanding that you plan to make the knurler "body" from one piece of stock that spaces the plates? If so then that would be an interesting approach, Chuck, one that I hadn't thought of. The reason I made mine as separate plates was so I could drawfile the plates to obtain near zero clearance with the arms. In my case, it worked well. I don't see how that could be accomplished with a solid frame but then again, I haven't tried it so I don't know.

If you do this, let us know how it works out because it eliminates the need to make spacers. I can tell you that it takes a bit of machining accuracy to make spacers that are exactly the same length; to get two, I had to make three and toss one. The two I kept were identical but I had to pay attention to make them.

 

[mickri]

I don't have material on hand to make the plates but I do have the 2x1.25 flat bar. After hogging out most the slots I am thinking that I would mill one side of the slots top and bottom without moving the table in the Y direction for the final cut. That should keep that side all in the same plane. Then move over to the other side of the slot and carefully mill it until the arms are a tight fit. Again making the final cuts without moving the table in the Y direction. Making it out of one piece would also ensure that all of the holes are in perfect alignment. I know my skill level. I seriously doubt that I could get all of the various pieces aligned and the same length. It might be awhile before I get to this. Temps in my garage/shop have been in the high 30's to the low 40's. Too cold for me. Burrrrrrr.

 

[mickri]

Made some revisions to my knurling tool. First up I don't need the extra .500 length for a slot for tool bits. So I shortened the base to 2". It is now 2"x2"x1.25". Next since this is a purpose built holder for just the knurling tool I don't need a height adjustment screw. I will attach the knurling tool to the holder so that it is centered at center line height. The base got flipped end for end and the knurling tool sticks out 1/4" from the base for clearance.

So easy to make these kind of changes in Sketchup. Mikey I could never master any of the CAD programs. Tried Sketchup and found it very easy to use. It's free. Download Sketchup Make 2017. SketchUp Make 2017 - Free download and software reviews - CNET Download It is the last version of Sketchup that you can download. The newer versions can only be used online. And get the book Sketchup for Dummies. You can make your drawings to .0001. I can't even machine to .0001 You will be making 3d drawings in no time at all. I will write a tutorial for you on how to draw your knurling tool. Step by step.

This is where I am at now.

 

[Grinderman]

Finally got my knurler done today. I got a lot of inspiration from Mikey's build but changed some things based on the materials I had on hand. The cheek plates are 3x3 and the arms are 3/4" square. I used shoulder bolts for the arm pivots and the other parts are all 1018. I had an old 1/4" solid carbide end mill that was junk so I cut that up for the wheel axles. It has a capacity of 0-2 1/2.
With the non beveled wheels the technique is a little different. I found a post from a guy who said he's been knurling for 30yrs and followed his plan. Bring the tool up and approximately center the wheel axles over the work piece. Bring the wheels down until they just touch. Back the tool out and place a piece of stock up against the work piece, then bring the tool in so the wheels just touch the stock, zero your cross slide dial. Add the thickness of the stock, half the diameter of the wheels and half the diameter of the workpiece together and dial the cross slide in that amount. Now you're on center of the workpiece. Set up a stop or indicator to be able to return to that point.
I then tighten the tension knob down about a half turn and feed it in until you hit the stop. If it looks good you're done, if not tighten a little more and try again.
I will probably buy some convex wheels at some point to be able to feed from the end. It makes great knurls on brass
and aluminum and not too bad even on crappy old 1018. Very happy with the outcome.
Forgot to add that this was made without a mill. I used my lathe with milling attachment. Sure would have easier with a mill. Some day hopefully. I also sacrificed my old bump knurler that came with the tool post for use here by cutting the ears off that held the wheels, milled the slot all the way through and added a couple more set screws.

 

[mickri]

For those who like to see dimensions here they are.

 

[mikey]

Finally got my knurler done today. I got a lot of inspiration from Mikey's build but changed some things based on the materials I had on hand.

Forgot to add that this was made without a mill. I used my lathe with milling attachment. Sure would have easier with a mill. Some day hopefully. I also sacrificed my old bump knurler that came with the tool post for use here by cutting the ears off that held the wheels, milled the slot all the way through and added a couple more set screws.

Nice job! Show us some knurls when you get the chance.

 

[Grinderman]

These are some of the first knurls, first time using the tool. 360 brass, 6061 AL and 1018 on the tensioning knob on the tool. Definitely a learning curve with this tool, should improve the more I use it, but satisfied for the shop knobs I make. If you're making a static knurl, how long do you let it dwell before backing off?

 

[Grinderman]

I watched a good video by Joe Pi this morning on knurling. His approach is very simple, bring the tool just behind the centerline of the work, crank down the pressure and run it. I found this couldn't be done with the tensioning knob I had made, so I made a new one out of a piece of hex stock I had on hand. I added a witness line to keep track of where I am if I need to repeat. Works great, easy to do.