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Making parts for a 13" steady rest

Thanks for the video link. Maybe try using your 123 block between that faced boss on the carriage and the dial indicator tip to then pre set your indicators fixed position when you need more distance than the indicators 1" travel. That's a bit faster and easier than moving the indicator in steps to more than a 1" distance. Any lengths of micrometer setting rods you happen to have can also do the same. Ok it's a bit less accurate than a proper dro, but it's certainly within a couple of thou and good enough for most parts.

If you've already done this in CAD and it appears so, or unless you want to keep them private, then posting your drawings here could help anyone in the future to also make the same replacement parts for those 13" steady's.
 
Thanks for the video link. Maybe try using your 123 block between that faced boss on the carriage and the dial indicator tip to then pre set your indicators fixed position when you need more distance than the indicators 1" travel. That's a bit faster and easier than moving the indicator in steps to more than a 1" distance. Any lengths of micrometer setting rods you happen to have can also do the same. Ok it's a bit less accurate than a proper dro, but it's certainly within a couple of thou and good enough for most parts.
This is a brilliant idea. Thank you! But, where were you a few days ago. LOL!

If you've already done this in CAD and it appears so, or unless you want to keep them private, then posting your drawings here could help anyone in the future to also make the same replacement parts for those 13" steady's.

Let's see how they turn out first.
 
Thanks, but that 123 block or micrometer setting rod idea sure isn't mine since most of it was borrowed from what the old school jig borers and grinders used before dro's were invented. It's just an expanded version of what your already doing. What we might be using is a whole lot less accurate than what they did since they were boring and grinding to repeatable coordinates and to less than 10ths accuracy. But it's still the same general idea.
 
Thanks, but that 123 block or micrometer setting rod idea sure isn't mine since most of it was borrowed from what the old school jig borers and grinders used before dro's were invented. It's just an expanded version of what your already doing. What we might be using is a whole lot less accurate than what they did since they were boring and grinding to repeatable coordinates and to less than 10ths accuracy. But it's still the same general idea.
True, but ballpark is all I really needed on this anyway. But that trick will come in handy for the next ops.
 
Loose the chuck try turning between centers , your work will end up more consistent .
I know when I started not using my 3 jaw as much my work improved quit a bit .
animal
 
A couple of other things from my learning the hard way .Use the carriage lock when facing & parting off . And I like to use my boring bars upside down & cut on the back of the material
that way it's easier to see how your doing until it's buried inside the work & if you get to the buried part ok you should be ok for the rest of the bore . You can also do your threading upside down on the back of the material too . I hope that makes sense . Maybe someone can explain it better ?
It looks like your on the right track . Good luck with the rest .
thanks
animal
 
Yep I'd very much agree, if concentricity is important enough, then between centers is my method of choice. Not possible with the bored hole and single pointed threads though. I suspect turning between centers is rarely mentioned on the other forums here even with it's superiority and speed while flipping the part end for end is simply because the usual drive method can't withstand the deeper cuts and high rates of feed used during industrial parts production. So they use larger collets much more often than we might. You still see it used a lot while finish grinding because of that concentricity. But the cutting loads are obviously lighter so it works just fine. In a home shop it's faster and more accurate than any chuck including 4 jaws and the best dial indicators. I use a stepped piece of scrap with a 60 degree point turned on it as a piece of semi disposable tooling so you don't even have to remove the chuck. Re-turn it's point each time it's used in the chuck and it's then as concentric as the head stocks spindle bearings will allow.

There's no real need for your parts OD to be exactly concentric to it's ID, eyeball concentric would be good enough. With how your 3D printed test piece is shaped, I'm assuming your going to knurl them to replicate the OEM parts as closely as possible? Even a scissor type knurling tool will put a lot of radial & axial load on those short and now harder to hold parts. It's hard to say for sure, but you might get forced into machining a stepped and threaded mandrel with a male thread to match the parts female threads and with centers on each end of it. Then the reduced step at the one end and the knurling could all be done at a single setting. Or even easier and before turning the OD to size, you could turn a fairly short and narrow 60 degree female angle at each end of your parts instead.
 
but you might get forced into machining a stepped and threaded mandrel with a male thread to match the parts female threads and with centers on each end of it.

That's a brilliant suggestion. Especially since it's almost EXACTLY what I said I was going to do at the end of the video. 🙄

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I'm a hobbyist that is still learning. Yes, I could have done things better. I may never "get there" but life is about the journey, not the destination.

 
Looks to me like you have things under control
That's a stretch. LOL!. Sometimes close enough is close enough. We'll see how it goes this week. Hoping for cooler temps. My shop is well insulated, but no climate control. So when it gets really hot in there, it stays hot. Opening the doors and windows just sucks in all the humidity.
 
Those came out pretty good. As you mentioned in the video, the clamp or scissor type knurling tools allow the high loads to be taken up by the tool itself and much less so by the head stock bearings, tail stock live center, cross feed screw and nut. So maybe a few thoughts for any future knurling jobs. Knurl quality and there sharpness are ultra important since anything lesser directly replicates itself into the knurl being formed. Poorly formed & dull knurls cannot produce a sharp, distinct and even pattern. So industrial brand name quality knurling wheels are very much worth what they cost. And how rigidly the knurling tool itself is would be just as important with those scissor type knurling tools. Light weight arms, poor fitting wheel axles, or any slop in the tool itself won't allow even the best knurling wheels to operate correctly. All the off shore clamp type knurling tools and a whole lot of the shop made designs seriously fail on just those issues. I bought an Eagle Rock knurling tool and it's built like they need to be. Certainly not cheap, but worth what it cost.

My opinion only, but on parts where a lot of time is being invested and expectations for good surface finishes as well as high quality knurling isn't where I'd be using any material with unknown specifications. And knurling has as you already know very high loads being applied into both the part and the lathe. It's basically a forced impression that extrueds the material into shape. I also would have kept your mandrel as short as possible with barely enough room for the tooling being used between the chuck and live center. The absolute minimum and no extra. And I probably would have done the knurling first as soon as the internal machining was finished. Then you do the rest of the external machining. You need to keep the set up and the part features as rigid as possible during that knurling. Even more so for those push type tools. The process also tends to have flakes of metal coming off, and vastly more if the knurling is taken too deep since there's no where left for the material to flow to so those knurling tips start to break off. Unless those are being flushed off as quickly as possible, they circulate between the part and those wheels. That works to defeat the point for why you spend what they cost on sharp and expensive knurling wheels. And since I don't have flood coolant on my lathe, then once the knurling is almost to full depth I'll usually detail clean both the work and wheels with something like a short bristle brush and either a solvent or a spray of WD 40, then apply lots of oil and make what I hope is the final pass. Well formed diamond pattern knurling should just come to sharp points or a few thou under that. If they do feel too sharp, then a very fine tooth file is used to barely dull the tips and soften there feel to your hands and fingers. And I'm not always successful getting the best knurling pattern I'm expecting either. There are a lot of variables involved. The more you practice at it the fail to success ratio seems to get a lot better.
 
Thanks for that feedback. When I come up on my next knurling project, I will be reconsidering using this push type knurling tool. As a hobbyist, I can't always justify the tools that are worth what you pay for them, mostly because of how often they would or would not be used, or even how much "I care" about the results. I think as I learn more, I will be much more willing to spend more money on the right tools. I mean, if you were going to start learning to play the guitar today, it's highly unlikely that the first thing you'd do would be to buy a vintage 1960s Fender Telecaster, even though it has the best sound of any guitar ever made. ;)
 
Very true, but with the same logic you shouldn't buy a little red wagon when what you really need is a freight truck.:-) Whatever I posted is true for any compression type knurling tool so it still wasn't wasted in case you decide you don't need better. The push type tool you already have has proven they can work fine, and afaik were the only type available if you go back far enough. There main deficit is there a bit harder on the lathe components. Knowing that and in a home shop it probably doesn't matter that much.
 
Disaster averted twice (at least) on this part. Sometimes, the best way for me to learn is to make mistakes. Luckily, nothing was so bad that I had to start over.

 
Finished the last machining on the steady rest parts. Minus one design mistake that was easily remedied, this project is DONE!

 








 
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