Machining a rod

S

Scruffer

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My newbie question. I have a sewing machine that has a knee lifter. It's a rod that is irregular"L" shaped. It inserts into a socket on the sewing machine. The rod end has two opposite splines that mate with the socket. The rod end is too large to insert into the socket. Probably a few thousands to large. The diameter of the rod is 5/16". Aside from just just securing it to a bench vise and sanding or filing it down, is there a way to machine the end. I do have a mill and a lathe. I don't know how I would secure it. One leg is approximately 6" long & the other 16" long with a dog leg in it.IMG_0611.jpgIMG_0611.jpg The purpose of the knee lifter is to facilitate lifting the presser foot while sewing. You just side shift the rod with your knee and it lifts the presser foot. It really helps when your sewing fabric with different thicknesses. Like redoing helms on jeans. The knee lifter that came with the sewing machine has never been used and now that I am putting it to use, it will not fit into the knee socket. Thanks
 
if it's really just a few thousandths I'd do it by hand, to easy to overshoot otherwise.

John
 
A file and a caliper would make quick work of it.
 
Looks like it was hammer forged/pressed to create the dog ears. Probably worn dies and/or if it's chromed the finish is too thick. And/or the mating part is contributing.

My answers:
If you really wanted to I'd say rotary table + block + V blocks in the mill if you want it round. But b/c of the shape you'd need some tall blocks to hold it upright & have any prayer of it not turning into a tuning fork.

If you have a collet closer you could probably mount it on the lathe cross slide. Indicate it in square & throw an end mill in the lathe spindle. Tight collet but barely loose enough to let you rotate the part. To get both sides you'd need to do it with the part in between you and end mill & then on the far side of end mill.

*******
Or same setup but with a boring bar in a 4 jaw chuck. Now that I've typed it out that sounds like both the easiest & most sane way of doing it.

But that's only if you have some kind of adjustable height collet closer like for a tool post. Otherwise it could be a major pain to make it coaxial with the lathe spindle.
*******

For flat work I'd just use V blocks in the mill.


What I'd probably do:
Is it just the dog ears or will the remaining rod end not fit at all?

If it's the entire rod it's probably just not round anymore. If there isn't one already, I'd add a tiny chamfer with your hand tool of choice, throw some dykem on it, then try to insert it & wiggle a tiny bit in the orientation it's supposed to be in.

Then hit it with a Dremel/whatever a bit where the dykem has been disturbed. They rinse & repeat until you're good to go.

If it's the ears I'd do the same thing, just skip the preceding material removal.

Honestly, it's probably a blessing. I've used the same thing and there's always been backlash that simply annoys the hell out of me & some machines don't have any kind of clamping.

Sent from my SM-N975U using Tapatalk
 
Iceberg86300 said:
Looks like it was hammer forged/pressed to create the dog ears. Probably worn dies and/or if it's chromed the finish is too thick. And/or the mating part is contributing.

My answers:
If you really wanted to I'd say rotary table + block + V blocks in the mill if you want it round. But b/c of the shape you'd need some tall blocks to hold it upright & have any prayer of it not turning into a tuning fork.

If you have a collet closer you could probably mount it on the lathe cross slide. Indicate it in square & throw an end mill in the lathe spindle. Tight collet but barely loose enough to let you rotate the part. To get both sides you'd need to do it with the part in between you and end mill & then on the far side of end mill.

*******
Or same setup but with a boring bar in a 4 jaw chuck. Now that I've typed it out that sounds like both the easiest & most sane way of doing it.

But that's only if you have some kind of adjustable height collet closer like for a tool post. Otherwise it could be a major pain to make it coaxial with the lathe spindle.
*******

For flat work I'd just use V blocks in the mill.


What I'd probably do:
Is it just the dog ears or will the remaining rod end not fit at all?

If it's the entire rod it's probably just not round anymore. If there isn't one already, I'd add a tiny chamfer with your hand tool of choice, throw some dykem on it, then try to insert it & wiggle a tiny bit in the orientation it's supposed to be in.

Then hit it with a Dremel/whatever a bit where the dykem has been disturbed. They rinse & repeat until you're good to go.

If it's the ears I'd do the same thing, just skip the preceding material removal.

Honestly, it's probably a blessing. I've used the same thing and there's always been backlash that simply annoys the hell out of me & some machines don't have any kind of clamping.

Sent from my SM-N975U using Tapatalk
Click to expand...
Thank everyone for the advice.
 
I do not have a collet closure. I do have a rotary table but lacking some blocks. The socket bore is .330 and the end of the rod is .336. It nice to get ideas on different approaches. I went with the dremel tool and removed about 8 thou off the end. Luckily, that's all it required. I am by no means proficient at sewing. It was my wife's sewing machine. She has since passed. I am short legged and when I buy pants, I am always dragging the cuffs. Sewing, another skill set I hope to acquire. LOL. Thanks again everybody.
 
You talking about the small end only ? Pics are terrible but if so .........................Take the blade out of a small pipe cutter and burnish the end till it fits . If that's not what you're talking about , forget it .
 
Glad you got it working easily.

Just for future reference, there are plenty of collet options for rotary tables that are very reasonable. Chucks as well. Some are bolt on, some fit whatever taper your rotary table has (if it has one).

Sorry for your loss, but welcome to the sewing hobby! Friends & family make fun of me b/c I'm a guy but it's an incredibly useful skill & makes me think of my grandma.

Sent from my SM-N975U using Tapatalk
 
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