Resettable Cross Slide Dial

[bmac2]

The one thing missing on my ML7 is a resettable dial on the cross slide. I wasn’t thinking of posting this but there might be something in it that someone can use so we’re going to jump in in the middle. The inner hub is pretty straight forward. There are 3 evenly spaced holes drilled 1/2” deep and a small recess in the back for a thrust needle bearing. The only tricky thing was the ¼ - 26 Whitworth thread on the cross slide lead screw. That’s not a tap that’s readily available and as I would probably not use it much I just made one. The graduated dial is a slide fit over the hub and held in place by 3 spring loaded balls riding in a recess on the inside.

As a side note to making the tap I discovered my 2800mw laser can mark metal.

 

[bmac2]

For scribing the dial I setup my trusty “Arduino controlled rotary table” on the lathe bed with the whitworth cutter in the tool post. Have you ever had one of those days when the 4 jaw chuck is fighting you? For whatever reason it took me over an hour to get setup dialed in.

 

[bmac2]

I have to say that with kquiggle’s Rev7.25 of the sketch this runs dead to nuts every time. Either I didn’t have it aligned with the lathe bed or just being a slide fit on the hub I had to go around twice to get the a depth I was happy with and it just lined up perfectly every time

 

[bmac2]

So much for the fun stuff. I procrastinated on stamping the numbers for quite a while thinking of different ways stamp on a cylinder and not have it come out looking like crap. I found the video “Making Larger Dials for the Logan Lathe” from Lyle Peterson (mrpete222/Tubalcain) where he made up a simple jig for holding the dial and keeping everything aligned.

https://www.youtube.com/watch?v=ygL7Se_E3wA

I clamped some 1in flat bar to the mill and bored it out so the graduated dial was a smooth slide fit and milled a 1/4” slot 1/4” deep to guide the number stamp. Luckily before I moved anything I realized that the stamping would raise the metal and opened up the bore just deep enough for a little clearance. I started the bore by drilling up to 3/4” and that ragged mess . . . . to say that my 3/4” drill bit is low quality is being overly polite but it will hog out a hole.

I wasn't sure about making that first strike but eventually you just have to have faith in the jig, trust the math for offsets and hit it with a hammer. All in all I’m pretty happy with the results.

 

[bmac2]

Oh the final assembly. This is where my great idea to have the outer ring float on the 3 balls became a bit of a challenge. Somewhere sort of East of my workbench are 2 balls and a spring (found 2 springs during cleanup). What I finally found that worked well was to put the springs into the holes in the hub and then insert it into the ring so it hung on the springs.

With a hose clamp set just smaller than the ring I could set the balls on the end of the springs with tweezers.

Then by tightening the hose clamp I could snap the hub down into the ring just like a installing a piston.

 

[bmac2]

I think when I made the tap I didn’t get the depth right. The thread in the hub is snug but that probably isn’t a bad thing. I was thinking of blackening the graduations but they stand out nicely when I’m in a working position and I think I’ll just let them get dirty on their own. All in all I pretty happy with the way It’s turned out.

 

[ShopShoe]

That does look nice. The knurling is good as well.

Congratulations,

--ShopShoe

 

[Bentwings]

That’s pretty clever work.

 

[Steamchick]

Bob. Lovely work, you obviously enjoy it for the pleasure of the process as well as the finished item. But I am a bit surprised you didn't re-sharpen the 3/4" drill.... and then told us it was rubbish! (OR maybe the speed was too fast? Been there, dunnit!). I found it amusing anyway. Just shows you are human I suppose...
K2

 

[awake]

Superb!

 

[Sprocket]

"Somewhere sort of East of my workbench..." I think I know where that is. I used to have to put in retainer balls where we would swage the ball in place,
(I think it was called "corking") but a lot of balls went awry! Gotta find humor in it.
Doug

 

[bmac2]

Thanks guys it was a fun project.

Steamchick. Ah the hobbyist nemesis feeds and speeds. The biggest problem with the bit is it’s a Powerfist. Now for Canadians that should pretty much sum it up. For everyone else Powerfist is a Princess Auto’s house brand for their budget tool line. You really do get what you pay for. It has a 1/2” drop down shank and a noticeable wobble when spun it in a chuck.