Swiss and Magical Guide Bushings

[John Deere]

OK, so my swiss knowledge is dated. I owned for a while a Citizen L25 that was about a '99 model or so. It has a standard rotating guide bushing. For a turning center guy it was a pain.

The sales guys are telling me all about these new guide bushings that self adjust. Claims that I can run regular old stock and everything will work hunky dory.

Realistically, I'd like to run 12L14 barstock that's not ground or any special prep. Is it reasonable to think we could hold sub .0005" total tolerances for size and roundness like this? Or is there some reason everyone hasn't thrown their regular guide bushings in the trash and swapped to new stuff?

Last, if a guy buys a Citizen with the guide bushing delete kit, does that system work as well as advertised?

 

[Nerdlinger]

I’m interested to hear others’ opinion on this. I know Star has had the “magic guide bushing” for some time and Tsugami started offering their version of it a couple years ago for something like $10,000. I’m not sure about Citizen but they’re usually ahead of the other two so it wouldn’t surprise me if they have it as well. The cost is the only reason I would think someone may want to skip it. No clue what the gb delete kit you speak of is. Good luck!

 

[Unahorn]

We have switched our 2 l20’s to the the adjustable guide bushings. Material still needs to be semi straight and diameter tolerance of .004 or so is fine. They have paid for them selves over and over. Not having to grind stock is a huge saving on money and time. We also did see tight tolerance parts be more consistent.

 

[TeachMePlease]

I've never used the magic guide bushings, but I have lots of friends in the Swiss world and the reviews from those that have them is quite favorable.

The Citizens don't really come with a "kit" to delete the guide bushing... You just pull the guide bushing out and go into your MC Structure page and tell it there's no guide bushing, that opens up the Z stroke soft limit so you can get the main all the way through where the guide bushing used to be. And yes, they work quite well when running in chucker mode. You can shorten up your remnants, make multiple parts per chucking, etc.

 

[Ox]

The equiv of the "Magic Guide Bushing" is the only option that my old 1990 Tornos does not have.
The button is there, but the feature is not.
Not sure if anyone else had it before 1990?

However - I found an outfit in Switzerland that makes retrofit kits for most machines, but they are $alty @ $20G USF.
With that said - their units take a rubber flex collet like the Hardinge Flex C. (not the Jacobs/Tapmatic type)
What is impressive with their unit is that is has a full 1mm of travel, while maintaining straightness - which a solid collet cannot doo.

The lady was telling me of one application that a customer was dooing, was starting with hot rolled and peeling it down.
Pulling it back in and then clamping down on that turned D, and with the moveable turret, was then able to doo other work to it that was concentric.


Solutions - Dunner

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Think Snow Eh!
Ox

 

[John Deere]

I'll ask my salesman but I see the Citizen Adaptive Guide bushing on a machine quote for $8900. Ya reckon this price is for the mechanism and then I'll need the bushing right? In other words not $9k per stock size I'd hope.

 

[Ox]

IDK Citizens, but I'm sure that's not per size.


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Think Snow Eh!
Ox

 

[Nerdlinger]

Last, if a guy buys a Citizen with the guide bushing delete kit, does that system work as well as advertised?

OH! If the "delete kit" is what TeachMe said then I know Tsugami's have the same dealy...they just call it, "running in chucker mode." Like TeachMe said, shorter remnants and no GB to futz with. I am not "pushing" Tsugami...it is just what I have so I'm sharing what I know about em. Good luck!

 

[John Deere]

OK now the next "brilliant" idea. Say a guy is running in chucker mode with no guide bushing. If you come grab the part with the subspindle and support it between the chuck and sub, how much does it help against chatter? Could a part with an L/D ratio of say 6:1 (.250" diameter and 1.5" long say) be turned well?

The exchange from Guide Bushing to no GB looks time consuming. The chucker mode would serve just about all of our parts well except for a few that are somewhat long.

 

[Ox]

Doo you have enough room on the end that does NOT need turned to chuck onto?

With the GB you can feed/turn it right into the sub and continue on, but if you are sticking out 6x, you_are_starting_out_at_6x.

If you had a center in it from before you feed out, you could use a live center during your turn opp eh?
Just place a live center in place of an endwerking drill or whatnot?
(IDK how your machine is configgered)


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Think Snow Eh!
Ox

 

[John Deere]

No machine configgered yet, just considering options before I purchase. Ran a Citizen with guide bushing some a long time back. Decided the guide bushing was evil.

I was thinking here chucker mode with say 1.5x length sticking out from chuck. Turn front end of part then grab with sub. Unchuck main and move back to 6x length. Then turn the remainder of the part and part off.

Works great inside my head, see? Maybe not so good in the real world though...

 

[DDoug]

Very nice Ox, but I wonder who would pay $20g and then stuff hot rolled thru it ?

 

[Ox]

Deere:

Your scenario sounds fine to me from what I understand.


Dig:

A36 is a whole lot cheaper than ground 1018.

Very applicable in tool steel jobs as well.


The HR is just an example of how far from the norm you could make work.
You can peel, and then come back and adjust down to the freshly turned diameter.

So it likely would work even better on basic CD materials?


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Think Snow Eh!
Ox

 

[Nerdlinger]

I’m not sure you’re giving the magic gb enough credit. IF it works as advertised are you good to go or are you more concerned about shorter remnants?

What you’re saying about turning a bit, grabbing with the sub, and going from there will work especially if you have a convenient feature to hide the inevitable mismatch line…like a shoulder or groove. Good luck!

 

[John Deere]

If it works as advertised then I guess I'm good to go. We'd be running cold rolled 1/2" 12L14 mostly so I can't complain too much about material costs from long remnants.

Let's say the magic guide bushing does work as advertised. If a guy had relatively short parts anyhow, is either GB or NO GB clearly better?

 

[Nerdlinger]

I suppose it depends on the shape of the part buuuut it doesn’t take much for the extra support provided by the gb to help..especially if you’re trying to hold .0005” IMO. Good luck!

 

[enginuity]

Some food for thought.

Firstly, Citizen's adaptive guide bushing is ok, but if you want to go the route of having an auto adjust guide bushing I recommend the JBS system. JBS System Whizcut is the North American distributor. WhizCut - Tooling for Swiss

The JBS system has a fair bit more travel than most others. And it's also being used by a number of builders - Tsugami is supplying from the factory (well sort of, REM Sales is installing them when they import them). The JBS system also has a hard clamp feature - basically locks the bushing solid. This is nice sometimes - you can't obviously feed in Z, but it does stiffen up the part for cross milling, drilling and slotting.

Auto adjust bushings aren't the solution to all your problems though. Firstly, if you use high pressure oil, it tends to pack chips into the bushing area. You need to give it a good clean out at least once a week. That said, you probably should be cleaning out your standard bushing this often as well. But it's not as big of deal with a regular guide bushing - the auto adjust ones have a cylinder on the back that moves the bushing back and forward. Get chips and there and they won't adjust properly.

That said, once you get them setup, get the feel of adjusting them the first time, and keep them clean, it's a set it and forget it experience.

As far as chucker mode - unless your material is super expensive, I personally love having the guide bushing there for support all the time. I can understand taking it out if you are making copper washers or something, but even with short 'ish' parts having that extra support really makes a difference in my opinion. I've run a few chucker type machines, and aside from the remnant, I prefer having the guide bushing there.

 

[DPM]

I haven't used a magic guide bush so can't speak to it's effectiveness. But I can tell you in the past 15 years I've been able to easily get by with the standard adjustable bushing on Citizens and Tsugamis and never considered the purchase of such a thing. Mostly running cold finished material for everyday Swiss suff and then getting into tight tolerance PG material for those very precise jobs. Yes sometimes a batch of cold finished bars will have to be sorted for size but it's not that big a deal.
Keep in mind that bar roundness is a big deal in the Swiss world and out of round bar shows up in your parts. So although magic guide bush can make up for bad material, it won't take the bad material out of the part in terms of roundness.

As for chucker mode...it's a mixed bag. Chucker is suitable for what I like to think are traditional screw machine parts with a little bit more open tolerances. You also can't feed all that hard like you would on a traditional lathe. Collet slips and rigidity becomes an issue. You gotta baby it unless it's brass or aluminum. So this will depend on your part mix. I would just summarize that if you're running traditional swiss parts then you'll want to stick with a bushing set up.