solid rod link machining question..

[CM9000]

machining solid rods for links is a new thing for me and is something I absolutely need practice with.

say I have a 6mm rod cut to a rough length needed. I want to put 8-32 threads on both of the rod ends 14mm in length. do I chuck the rod in a lathe and bring it down to 4mm in diameter? chamfer the ends just a bit to get the die to start cutting right?

I have access to a lathe. id like to get the ball rolling a bit farther down the road for my scaler build im currently working on. just need a few tips to help me out a little is all.

as far as I know right now I need to make 3 sets of links for 3 different axles ill be testing out under my rig. so I need all the help I can get.

 

[Gula]

Some lathes you can cut threads without a die

 

[QuesoDelDiablo]

I'll assume your machining out of aluminum?

While the threaded post idea can seem like a good one, in my experience you're better off going with a drilled and tapped hole. At those diameters, there's a good chance that the post will get twisted by the torque used to apply the dies.

To minimize the chance of that happening you should add a small chamfer at the base of the post to reduce the stress concentration, you should also put a slight bevel on the top of the post for the die to start easier.

As far as the diameter, by the book an 8-32 should be .164" before threading. People will often go about .005" under that to make the threading easier. 159"-.164"=4.0mm-4.2mm

This is a lower risk in aluminum or brass than if you were using steel. With softer metals, if you're careful you should be ok. In steel, I wouldn't even try posts , I'd go drill/tap.

 

[CM9000]

I'll assume your machining out of aluminum?

While the threaded post idea can seem like a good one, in my experience you're better off going with a drilled and tapped hole. At those diameters, there's a good chance that the post will get twisted by the torque used to apply the dies.

To minimize the chance of that happening you should add a small chamfer at the base of the post to reduce the stress concentration, you should also a slight bevel on the top of the post for the die to start easier.

As far as the diameter, by the book an 8-32 should be .164" before threading. People will often go about .005" under that to make the threading easier. 159"-.164"=4.0mm-4.2mm

This is a lower risk in aluminum or brass than if you were using steel. With softer metals, if you're careful you should be ok. In steel, I wouldn't even try posts , I'd go drill/tap.

Thanks for the reply, i have some steel bolts i cut the shafts from. I thought it would be easier to do this with steel. I guess i will have to just drill and tap.

Just thought since i have a set of stainless done the same way i should try it myself with a 6mm rod for the front and 5mm rod for the rear. But i guess ill just chuck em in the lathe and face em off. Drill then tap.

When tapping... Should i hand start on the lathe with the tap in the chuck and apply pressure with the chuck feed while i spin the lathe by hand?

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[CREEPERBOB]

And yes ,chamfer the end.I would thread with a die. A lot less breakage issues.

 

[CM9000]

I would thread with a die. A lot less breakage issues.

Im going to try it out both ways on both the 5mm and 6mm rod.

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[whitrzac]

Protip: most everything in the RC world is metric. The sooner you convert your thinking to make everything metric, the easier time you will have.

 

[Heckler]

If your going to do this on a lathe Im assuming you have a drill chuck for your tailstock to put the rod in, then put the die in the chuck of the lathe, leave the tailstock loose so the rod can move with the threads, most importantly do not power on the lathe, rotate the chuck by hand back and forth so you can "feel" it. With diameters this small you can easily break off the end of the rod if you use the lathe power to turn the die.

Unless of course you have a threading jig for your tailstock then it would be the other way around, but I would still turn it by hand with something this small in diameter.

 

[CM9000]

If your going to do this on a lathe Im assuming you have a drill chuck for your tailstock to put the rod in, then put the die in the chuck of the lathe, leave the tailstock loose so the rod can move with the threads, most importantly do not power on the lathe, rotate the chuck by hand back and forth so you can "feel" it. With diameters this small you can easily break off the end of the rod if you use the lathe power to turn the die.

Unless of course you have a threading jig for your tailstock then it would be the other way around, but I would still turn it by hand with something this small in diameter.

the drill chuck is on the tailstock. I might just cut the threads off the lathe, seeing as getting the die "zero" in the chuck of the lathe might be a little complicated for me.

though testing out both methods I will be able to drill and tap on the lathe pretty easy.

also 8-32 is a courser thread than a 4mm thread. hence why im using it. so the revo rod end would have a harder time pulling off of the threads.

thanks for the replies guys. going to test this out and take pictures along the way tonight!

 

[Ditchrat]

Protip: most everything in the RC world is metric. The sooner you convert your thinking to make everything metric, the easier time you will have.

But VP uses SAE, so it must be pro.:lmao:

 

[Robbob]

Protip: most everything in the RC world is metric. The sooner you convert your thinking to make everything metric, the easier time you will have.

While true you have to remember, rock crawlers arent your normal RC World vehicle. :ror:

Coarse threads can have a bigger benefit for crawlers. ;-)

 

[CM9000]

Made some passes. Drilled a hole. Tapped it. Wish i had a bottom tap handy. Now im comfortable with making some links.. I might look into getting a cheap lathe for making my own stuff.

This was done on a 3 jaw chuck lathe. Pretty small. I know i should make a few passes to true up the shaft and re chuck it. But i was just trying to get comfortable with it. Didnt have much time left to turn down the actual pieces i wanted to use. But i did face off both ends on one piece not pictured.

 

[CM9000]

maybe im missing something... but to me these pieces look a little rough.. am I going to slow? to fast? or is the cutting bit dull? or r is it because its a 3 jaw chuck? or is it all of the above? lol.

going to make some links today. buy some stainless rod on Friday and have my buddy copy the links. ill probably run my links for the class 2 trim on project TAZ in a comp and for a g6 event as they will be a bit heavier than the stainless im sure. keeping the weight down low is the only thing that's gonna help this 9 3/4 wheelbase truck.

if im doing something wrong please feel free and let me know.

 

[CM9000]

Id say not bad for my first try. What do you guys think?

 

[BigSki]

maybe im missing something... but to me these pieces look a little rough.. am I going to slow? to fast? or is the cutting bit dull? or r is it because its a 3 jaw chuck? or is it all of the above? lol.

going to make some links today. buy some stainless rod on Friday and have my buddy copy the links. ill probably run my links for the class 2 trim on project TAZ in a comp and for a g6 event as they will be a bit heavier than the stainless im sure. keeping the weight down low is the only thing that's gonna help this 9 3/4 wheelbase truck.

if im doing something wrong please feel free and let me know.

3 jaw chuck has nothing to do with the finish, it's all about speeds, feeds and the type of cutter used.

Which grade of stainless did you use? I recently made some links for my Dolt and posted a few pics, the 303 grade was considered to be the "easiest" to machine and it still gave me issues. Looks like you're doing good so far. "thumbsup"

 

[CM9000]

3 jaw chuck has nothing to do with the finish, it's all about speeds, feeds and the type of cutter used.

Which grade of stainless did you use? I recently made some links for my Dolt and posted a few pics, the 303 grade was considered to be the "easiest" to machine and it still gave me issues. Looks like you're doing good so far. "thumbsup"

I actually didn't machine the stainless. I just machined the ones pictured out of a grade 8 bolt shaft. 2 different sizes. brought one set from 9.87mm down to about 4.15mm and then threaded the ends using a 8-32 die in the chuck and the pieces in the end stock.

im having my buddy machine some links out of some "stainless" I don't know the grade of. just picked up the bar stock from my lhs.

I actually finished the links pictured. just haven't put rod ends on them yet.

since im comfortable with the lathe kinda sorta... I might try my hand at some brass so I can turn down some tlt shocks for more frame to shock clearance. right now on my build they are pretty close to touching.

I think I found my new addiction. the lathe.

 

[QuesoDelDiablo]

3 jaw chuck has nothing to do with the finish, it's all about speeds, feeds and the type of cutter used.

Which grade of stainless did you use? I recently made some links for my Dolt and posted a few pics, the 303 grade was considered to be the "easiest" to machine and it still gave me issues. Looks like you're doing good so far. "thumbsup"

I actually didn't machine the stainless. I just machined the ones pictured out of a grade 8 bolt shaft. 2 different sizes. brought one set from 9.87mm down to about 4.15mm and then threaded the ends using a 8-32 die in the chuck and the pieces in the end stock.

im having my buddy machine some links out of some "stainless" I don't know the grade of. just picked up the bar stock from my lhs.

I actually finished the links pictured. just haven't put rod ends on them yet.

since im comfortable with the lathe kinda sorta... I might try my hand at some brass so I can turn down some tlt shocks for more frame to shock clearance. right now on my build they are pretty close to touching.

I think I found my new addiction. the lathe.

In my limited experience, 303 is the only grade of stainless that's workable at the diameters we need.

I tried some 314 ground and polished drill rod (i think that's what it was - that was a while ago now), it was beautiful material but even the best machinist we have in town couldn't get a 3mm tap into it.

 

[BigSki]

Yuppers, the stainless work hardens right before your eyes. I was using a manual lathe and ended up using very high RPMs and basically plunged into the material and used a lot of pink BoeLube paste.

 

[QuesoDelDiablo]

Yuppers, the stainless work hardens right before your eyes. I was using a manual lathe and ended up using very high RPMs and basically plunged into the material and used a lot of pink BoeLube paste.

That BoeLube paste is magical stuff..

 

[BigSki]

That BoeLube paste is magical stuff..

"thumbsup" It's probably the only reason that I had success with the boring/tapping of the internal M3 threads in the 303.