Roller nut slots

[mac639]

Good day all! Hope I didn't upset anyone with my comments on the changer axle thread earlier. When I read it over online I thought perhaps I was a little too "smart" about my observations. Sorry!

Anyway, roller nuts. One of the worst things I do when I make a guitar is figuring out how to make a slot for the small axle that holds the rollers on top of the roller nut assembly. I just end up filing the slot with a round file chucked in my drill....not a great solution. How do you guys do it? I know it'd be easier with a small miller, but I don't have such an animal. And drilling with another piece of stock clamped to the top and drilling half into each piece doesn't work too good either as the drills are too short and you have to go from both ends and it never matches the first hole very good.
Any ideas?
Thanks so much
Mac

[Allan]

Hi Mac, Just thinking on the run here. How about running the nut body lengthwise over a table saw? You could make a jig to hold it firmly while making the slot. Another jig, along the lines of a finger joint jig, would allow for cutting the crenelated slots for the rollers. The whole thing could be made and virtually brought to the finished state then cut away from a larger piece.
I don't know if that is at all clear from the description, but if not, I will make a wee sketch to show what I am thinking. The only real flaw I can see right now is that the axle slot would be square on the bottom. I don't believe that would be a project killer though.

Regards, Allan.....

[mac639]

I'm scared to death of my table saw.....especially if wanted to run some aluminum through it. Bent did though I think, making some bellcranks. The idea is good though, I even dragged out my biscuit joiner after reading your response. That might work also but the cutter is 3/16" wide so I don't know.
Anyway, I'm still thinking on other possibilities. If I could figure out how to mount the thing on my lathe I could do it with a 1/8" abrasive cutoff wheel.
Cheers,
Mac

[ljs]

Hi Mac,
I don't know what kind of a lathe you have, but you can get or make a milling atachment that will bolt onto your cross-slide of your lathe and provide vertical movement for a piece clamped into it.

http://www.deansphotographica.com/machi ... hment.html

There are some photos of such an atatchment showed towards the bottom of the page at the above link. The very bottom photo shows a pretty good depiction of how it works. The lathe spindle provides the turning power for a mill and you would clamp your stock that you want to mill into the vise and after centering on the vertical line, you would move the milling vise up or down to mill your slot. You may find ideas on how to build this atachmnet or maybe even find on to purchase on line somewhere. It seems to me that I have seem plans on one of the home machinists web-sites. If I do find a link I'll post it.

LaVern Skarzenski

[ljs]

Hi All,
Here is another link to a milling adapter for a mini-lathe.

http://www.littlemachineshop.com/produc ... uctID=1681

This photo shows pretty clearly how it looks and works. This unit has 3.6" of travel, I don't know if that would be enough to mill the full length of the roller nut support assembly or not. I have bought items from these people previously and I am very satisfied on the amount of time to receive parts from them.
LaVern Skarzenski

[Bent]

Mac, No your remarks on the cab drop issue were not smartass at all. You had some good points. By the way, I just replied to that thread and my remarks are in your face type so I guess it makes us two birds of a feather.

As to your nut slots dilemma:
I can visualize the table saw coming in very handy here. No need to be afraid of trying it. You only need to observe 3 rules and never deviate from them:
- Be in full control at all times
-Make sure that your work piece is clamped VERY solidly
- Take shallow cuts. My rule of thumb here is: a 3/16" deep cut when using a regular 1/8" blade. When using a dado set, up to 3/8" wide, take a 3/32" deep cut.

For your nut, I envision making a jig that slides in both miter slots with a "bridge" type of thing straddling the blade. Use too much material so that you can fasten the material to the bridge with two #10 machine screws and nuts.
Start off with the blade up just enough to tickle the aluminum ( I would use a dado set wide enough for the roller slot). Then on the next pass, you have cranked your blade up an 8th of a turn observe that depth of cut... now you are learning how deep a 1/4 run or 1 half turn of the wheel will take you. As you cut you will know the exact crank of the wheel every time. Pass over the blade slowly. Pass over on the return before raising the blade ...and so on. Be there with your vernier calipers and "sneak up on" that last cut where you want the exact depth. Make a mental note of where your hand wheel is so you can work up to this location for the remaining cuts. Don't stand in the line of fire when cutting. Wear gloves. Make your jig so that you can have your pushing hand 5" away from the blade at all times.
Then all you have left is the actual cutting of the axle slot, which should be a breeze now, with most of the material gone. If you go for a 1/8" slot, use a 1/8" file. Start off with hacksawing a straight cut down the middle of the intended slot location and almost to the depth. This will guide your file.

[azureskys]

Mac i did this roller nut setup with my laythe mill combo