Making Bushings...

[TommyD]

We exclusively used 3 jaw chucks with soft jaws which we bored out to the dia of the pieces we were making. I apprenticed in a shop that made bearing seals and some of the molds had 144 cavities and we always made spares. We ALWAYS used the same chuck key hole, the one that was directly above the mfg badge, as well as coloring up the slug between the two jaws, we needed to do this to provide consistency from part to part.

 

[zboss86]

We exclusively used 3 jaw chucks with soft jaws which we bored out to the dia of the pieces we were making. I apprenticed in a shop that made bearing seals and some of the molds had 144 cavities and we always made spares. We ALWAYS used the same chuck key hole, the one that was directly above the mfg badge, as well as coloring up the slug between the two jaws, we needed to do this to provide consistency from part to part.

wow, that sounds like it's above my pay grade... lol, it is neat to hear what extremes some do provide the consistency and accuracy they need.

 

[maker of things]

It's sad, but I even had to read up on boring just to make sure I knew what you were referring to. That' d be an option too...

I don't see anything wrong with having to look up terms and processes. You have had your machine up and running less than 1 week and already knocked out at least 2 projects, that's nothing to sneeze at!

Boring vs reaming; if you will be doing a limited number of hole sizes, chucking reamers would make quick work of giving you that slight over size hole, but you have to buy a reamer for each size.
Boring will allow you to make the hole any size you want and when done the hole will almost always be more concentric. Don't think that is critical for this application, but you do have tooling already

 

[chips&more]

I have a Rohm 1/2" and a larger Jacobs drill chuck.
Both grip much tighter when I use the key in all three positions. The Rohm in particular has bad habit of spinning the bit on break through, it also does not grip taps very well unless I tighten all three holes - which makes for a nice safety feature with smaller taps. The Albrecht keyless I use on the lathe actually seems to grip better than the keyed Rohm. Maybe I got a defective unit, Rohm is supposed to be good.
I also always tighten all three holes on a 3jaw chuck. I have "decent" quality Chinese chucks, I would never trust the scroll to not wind up when chucking work.

All my chucks are Jacobs. And I guess are the USA made ones because I have had them for decades. No problems at all with them. They will probably outlive me! I also have many Albrecht keyless chucks that have found their way into my shop. Liked them at first, now they all collect dust. One of them tightened up so tight on a drill bit I had a heck of a time undoing it! AND I like to feel how tight I’m doing things. I can feel the tightness with a chuck that has a key. I cannot feel the tightness with the keyless.

 

[zboss86]

I don't see anything wrong with having to look up terms and processes. You have had your machine up and running less than 1 week and already knocked out at least 2 projects, that's nothing to sneeze at!

Boring vs reaming; if you will be doing a limited number of hole sizes, chucking reamers would make quick work of giving you that slight over size hole, but you have to buy a reamer for each size.
Boring will allow you to make the hole any size you want and when done the hole will almost always be more concentric. Don't think that is critical for this application, but you do have tooling already

Good point, I think I also have some reamers... I just need to see what sizes I have.

Next question...
When turning down the outsize diameter... Example ~.75" diameter- cold rolled steel.
I haven't been able to get the surface as smooth as I'd like. It's still somewhat coarse... I was fortunate that these bushings didn't really need to be turned on the out side, I just hit them with 80 grit sand paper and a scotch brite at a high rpm. Is there a particular bit I need or a certain rpm I need to be running? I tried running a small cut but, it was still leaving a rough surface. I've ran different bits at different angles, but they all leave the same texture. I'll grab some pics of what I'm talking about tonight.

 

[TommyD]

Is your toolbit on center?
Smooth radius on the tip of your tool bit?

Either could be the problem. To tell if your bit is on center, face a piece fron the od to id, being careful as you get towards the center. You can be low on center, not ideal but ok, on center which is ideal or above center, which you do not want. Above center results in chipped out bits since the tit rubs on the relief flank of the bit, chipping it out. This is important for facing as well as turning.

I don't use hss bits, never really did, I'm spoiled using carbide.

 

[TommyD]

It also could be feed speed, too fast for rpm of piece. Hard to tell without seeing it.

 

[Wreck™Wreck]

Next question...
When turning down the outsize diameter... Example ~.75" diameter- cold rolled steel.
I haven't been able to get the surface as smooth as I'd like. It's still somewhat coarse... I was fortunate that these bushings didn't really need to be turned on the out side, I just hit them with 80 grit sand paper and a scotch brite at a high rpm. Is there a particular bit I need or a certain rpm I need to be running? I tried running a small cut but, it was still leaving a rough surface. I've ran different bits at different angles, but they all leave the same texture. I'll grab some pics of what I'm talking about tonight.

Spindle speed and feed rate, I would turn 3/4" diameter CRS at no less then 2500 RPM's at .006 IPR feed in order to get a decent finish with carbide, maybe 1/2 the spindle with HSS tooling.

 

[Silverbullet]

I have a Rohm 1/2" and a larger Jacobs drill chuck.
Both grip much tighter when I use the key in all three positions. The Rohm in particular has bad habit of spinning the bit on break through, it also does not grip taps very well unless I tighten all three holes - which makes for a nice safety feature with smaller taps. The Albrecht keyless I use on the lathe actually seems to grip better than the keyed Rohm. Maybe I got a defective unit, Rohm is supposed to be good.
I also always tighten all three holes on a 3jaw chuck. I have "decent" quality Chinese chucks, I would never trust the scroll to not wind up when chucking work.

The only way that should make the chuck hold tighter is if the jaw scrolls are worn or loose. I've used many chucks and it's usually the worn out or abused ones that act like that. I prefer a keyed chuck to a hand tite unless it's an albrectt chuck those buggers self tighten .

 

[P T Schram]

To reply to the primary question, I recently finished 26 misalignment bushings for a four link

I start with 1/8",then, 1/4 or 3/8, then 1/2, then either 5/8 or 3/4, but mine are made of tool steel versus CRS.

This operation convinced me of the need for a tail-stock turret

The spacers for my three link will be easier

If you don't have one get a copy of "How to Run a Lathe"


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