whodat
03-11-2020, 07:46 PM
A friend I haven't met yet reached out and asked me if I could make a shifter tip replacement (SM6) that's longer than stock so I said I'd take a look. I figured it'd be easy, a couple of round bits welded together with some flat bit in the middle. Turns out the stock shifter tip is splined, which added a whole degree of difficulty. Anyhow, there were 8 splines so I figured I'd give it a shot.
https://live.staticflickr.com/65535/49649348383_70a69b840b_c.jpg (https://flic.kr/p/2iDkTvZ)Untitled (https://flic.kr/p/2iDkTvZ) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
I made an attachment for my lathe a while ago that allows me to index the chuck to 60 plus 4 points, which gives me a lot of divisors. The plus 4 is what allows me to index by 8. I also made an attachment that lets me mount my cordless drill to the toolpost. This is what I did here.
https://live.staticflickr.com/65535/49649919711_7713777c63_c.jpg (https://flic.kr/p/2iDoPmt)Untitled (https://flic.kr/p/2iDoPmt) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
This is the end result, a series of 8 holes drilled into the end of a random chunk of steel I had laying around. Note that this took multiple tries of different size drills, different diameter hole patterns, and feeds/speeds.
https://live.staticflickr.com/65535/49649885756_b84f73844d_c.jpg (https://flic.kr/p/2iDoDg3)Untitled (https://flic.kr/p/2iDoDg3) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
After turning to diameter, this is what I'm left with. Splines! If I had any of a number of other tools I could have made them differently, but that's what I had that didn't involve lots of filing or dremel tool work.
https://live.staticflickr.com/65535/49649381563_611ffbbc61_c.jpg (https://flic.kr/p/2iDm4o4)Untitled (https://flic.kr/p/2iDm4o4) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
The stock part has a recess in the middle of the splines to allow the locking bolt to positively retain it. Again, other tools would have made this easier but I mounted a 1/4" end mill in my drill rig then turned the lathe on and ground the groove out.
https://live.staticflickr.com/65535/49650159162_63cf373b2b_c.jpg (https://flic.kr/p/2iDq3wW)Untitled (https://flic.kr/p/2iDq3wW) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
Proof of concept part, before cleanup and deburring.
https://live.staticflickr.com/65535/49649916556_479b7106b2_c.jpg (https://flic.kr/p/2iDoNq5)Untitled (https://flic.kr/p/2iDoNq5) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
Installed in the shifter.
https://live.staticflickr.com/65535/49650161142_feeae1d280_c.jpg (https://flic.kr/p/2iDq485)Untitled (https://flic.kr/p/2iDq485) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
Then I milled a slot about a hundred thousandths deep across the center of the top.
https://live.staticflickr.com/65535/49649380053_88617dae14_c.jpg (https://flic.kr/p/2iDm3W2)Untitled (https://flic.kr/p/2iDm3W2) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
And cut a chunk of scrap 1/8" steel down to the same size as the slot
https://live.staticflickr.com/65535/49649886386_55ef4c000d_c.jpg (https://flic.kr/p/2iDoDrU)Untitled (https://flic.kr/p/2iDoDrU) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
So it fits into the slot tightly
https://live.staticflickr.com/65535/49649917991_8130698cbf_c.jpg (https://flic.kr/p/2iDoNQP)Untitled (https://flic.kr/p/2iDoNQP) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
I took an old pin that broke off one of my trailers and turned this piece out of it to size
https://live.staticflickr.com/65535/49650219557_6f8c57d748_c.jpg (https://flic.kr/p/2iDqmue)Untitled (https://flic.kr/p/2iDqmue) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
Then drilled a matching hole in the flat bar and pressed the turned part in
https://live.staticflickr.com/65535/49650161397_a332951164_c.jpg (https://flic.kr/p/2iDq4ct)Untitled (https://flic.kr/p/2iDq4ct) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
The fit was tight enough that I could do a fusion weld from the back. Got a bit hot and melted the edge there, but I'm not awesome at tig welding yet.
https://live.staticflickr.com/65535/49650162607_b90f3442d4_c.jpg (https://flic.kr/p/2iDq4yk)Untitled (https://flic.kr/p/2iDq4yk) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
New part next to the stock part. I'm waiting to hear how much longer than stock he wants it before I adjust it to final length and weld it solid.
Edit: I currently have from -.5 to +1.7” adjustment range. Honestly it wouldn’t be all that difficult to make it adjustable too, although I’d have to change the design and redo it all.
https://live.staticflickr.com/65535/49649348383_70a69b840b_c.jpg (https://flic.kr/p/2iDkTvZ)Untitled (https://flic.kr/p/2iDkTvZ) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
I made an attachment for my lathe a while ago that allows me to index the chuck to 60 plus 4 points, which gives me a lot of divisors. The plus 4 is what allows me to index by 8. I also made an attachment that lets me mount my cordless drill to the toolpost. This is what I did here.
https://live.staticflickr.com/65535/49649919711_7713777c63_c.jpg (https://flic.kr/p/2iDoPmt)Untitled (https://flic.kr/p/2iDoPmt) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
This is the end result, a series of 8 holes drilled into the end of a random chunk of steel I had laying around. Note that this took multiple tries of different size drills, different diameter hole patterns, and feeds/speeds.
https://live.staticflickr.com/65535/49649885756_b84f73844d_c.jpg (https://flic.kr/p/2iDoDg3)Untitled (https://flic.kr/p/2iDoDg3) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
After turning to diameter, this is what I'm left with. Splines! If I had any of a number of other tools I could have made them differently, but that's what I had that didn't involve lots of filing or dremel tool work.
https://live.staticflickr.com/65535/49649381563_611ffbbc61_c.jpg (https://flic.kr/p/2iDm4o4)Untitled (https://flic.kr/p/2iDm4o4) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
The stock part has a recess in the middle of the splines to allow the locking bolt to positively retain it. Again, other tools would have made this easier but I mounted a 1/4" end mill in my drill rig then turned the lathe on and ground the groove out.
https://live.staticflickr.com/65535/49650159162_63cf373b2b_c.jpg (https://flic.kr/p/2iDq3wW)Untitled (https://flic.kr/p/2iDq3wW) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
Proof of concept part, before cleanup and deburring.
https://live.staticflickr.com/65535/49649916556_479b7106b2_c.jpg (https://flic.kr/p/2iDoNq5)Untitled (https://flic.kr/p/2iDoNq5) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
Installed in the shifter.
https://live.staticflickr.com/65535/49650161142_feeae1d280_c.jpg (https://flic.kr/p/2iDq485)Untitled (https://flic.kr/p/2iDq485) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
Then I milled a slot about a hundred thousandths deep across the center of the top.
https://live.staticflickr.com/65535/49649380053_88617dae14_c.jpg (https://flic.kr/p/2iDm3W2)Untitled (https://flic.kr/p/2iDm3W2) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
And cut a chunk of scrap 1/8" steel down to the same size as the slot
https://live.staticflickr.com/65535/49649886386_55ef4c000d_c.jpg (https://flic.kr/p/2iDoDrU)Untitled (https://flic.kr/p/2iDoDrU) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
So it fits into the slot tightly
https://live.staticflickr.com/65535/49649917991_8130698cbf_c.jpg (https://flic.kr/p/2iDoNQP)Untitled (https://flic.kr/p/2iDoNQP) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
I took an old pin that broke off one of my trailers and turned this piece out of it to size
https://live.staticflickr.com/65535/49650219557_6f8c57d748_c.jpg (https://flic.kr/p/2iDqmue)Untitled (https://flic.kr/p/2iDqmue) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
Then drilled a matching hole in the flat bar and pressed the turned part in
https://live.staticflickr.com/65535/49650161397_a332951164_c.jpg (https://flic.kr/p/2iDq4ct)Untitled (https://flic.kr/p/2iDq4ct) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
The fit was tight enough that I could do a fusion weld from the back. Got a bit hot and melted the edge there, but I'm not awesome at tig welding yet.
https://live.staticflickr.com/65535/49650162607_b90f3442d4_c.jpg (https://flic.kr/p/2iDq4yk)Untitled (https://flic.kr/p/2iDq4yk) by Uncle Grr! (https://www.flickr.com/photos/unclegrr/), on Flickr
New part next to the stock part. I'm waiting to hear how much longer than stock he wants it before I adjust it to final length and weld it solid.
Edit: I currently have from -.5 to +1.7” adjustment range. Honestly it wouldn’t be all that difficult to make it adjustable too, although I’d have to change the design and redo it all.