Swiss screw machines, bushing or no bushing

CBlair · Feb 27, 2012

It would seem that not having a live bushing for the tools to cut against would limit the length of the part you need to make. But it also adds a lot of cost to the process. If you only need to make short parts, and you still have the option of turning on the subspindle then it would seem that not having the bushing would be a benefit.

For those of you who have swiss type screw machines how many of you run the machines with a bushing and how many without. Are there any other advantages to one over the other?

Charles

stumpwater · Feb 27, 2012

support bushing

CBlair:
If your machine was made to run a bushing then you had better not try it without one. On most sliding headstock machines there is just too much lenght from the headstock collet to the cutting tools, even for short parts.
Mike

CBlair · Feb 27, 2012

Dont have one, yet, just trying to educate myself on the differences between them.

Charles

Ox · Feb 27, 2012

Mine has a bushing. Only the new ones have the option of not.

Those with that option have extended Z travel that has the ability to run collet up to the tool.

IMO - if a guy was to have one machine, one with this option would be just the ticket. IMO it would give you the best of both werlds!

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I am Ox and I approve this h'yah post!

PixMan · Feb 27, 2012

There are machines from Tsugami and some others that are "convertible" from guide bushing machines to chuckers.

Well worth looking into if in the market and you do a lot of short parts. It usually requires a change in Z1 axis limit and bar feeder end-of-bar position when switching back & forth.

MikeMc · Feb 28, 2012

WAY back, in the dark ages when I used to run cam machines, we would run them without the guide bushings for short stainless parts, and they worked out pretty well. I couldn't imagine doing it now, the conversion time seems like it would add way too much to the set-up IMO.

CBlair · Feb 28, 2012

I saw were Citizen had machines with either one or the other and I was curious how many people chose the non bushing route.

Charles

PixMan · Feb 28, 2012

MikeMc said:
WAY back, in the dark ages when I used to run cam machines, we would run them without the guide bushings for short stainless parts, and they worked out pretty well. I couldn't imagine doing it now, the conversion time seems like it would add way too much to the set-up IMO.

In running those (or any) machines the setup time is buried within the total "uptime" of making good parts. It's always a good thing to reduce setup times to the minimum, but regardless it's something that is reduced in cost-per-part as the number of parts made for a single setup increases.

I have run Tsugami (and one other brand I won't ever mention again) that had the option of guidebushing or not. Removing the guidebushing adds perhaps 5-7 minutes in setup to remove it, a little more when it needs replacing.

The cost of that changeover can be recovered in something as simple as getting few more parts per bar from having a shorter remnant length.

Ox · Feb 28, 2012

WOW!
That quick eh? :eek:

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I saw were Citizen had machines with either one or the other and I was curious how many people chose the non bushing route.

Charles

Are you sure about that?
I have a very hard time believing that.

I bet you just mis-understood. It may be that some models are configured so that you can remove it, and some models are still old skool.

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I am Ox and I approve this h'yah post!

CBlair · Feb 29, 2012

Ox said:
WOW!
That quick eh?

----

Are you sure about that?
I have a very hard time believing that.

I bet you just mis-understood. It may be that some models are configured so that you can remove it, and some models are still old skool.

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I am Ox and I approve this h'yah post!

Ox here is the PDF page where the A32VIIC is listed as no guide bushing.....I dont know, I just work here.

http://www.concentriccorporation.com/PDFs/A32.pdf

The version with the guide bushing has over 300mm of stroke were the non guide bushing one has only 85mm of stroke.

Charles

Ox · Feb 29, 2012

CBlair said:
Ox here is the PDF page where the A32VIIC is listed as no guide bushing.....I dont know, I just work here.

http://www.concentriccorporation.com/PDFs/A32.pdf

The version with the guide bushing has over 300mm of stroke were the non guide bushing one has only 85mm of stroke.

Charles

The layout shows a bushing layout, and I see no mention of that machine being able to remove it.

As well - the build sheet lists the bushing number.

Guide bushing TD32

OK - I see now that they are listing two versions of the machine. You are refering to the "C" model eh?

I wonder if that is really that short of Z travel, or if it is an additional 85mm of travel if you remove the bushing assy?

I can see them possibly limiting the travel as you have no business trying to take a cut on .625 stock 4" out from the chuck? But in reality, we doo git jobs at times that we doo exactly that. So ???

If this machine is really not "convertable" and is either one way or the other, it would seem that they are really hanging out there on marketing to me. ???

Now if the "removeable" machines weren't developed yet, I could maybe see it. But to think that you would try to sell a non-bushing only machine these days? :skep:

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Think Snow Eh!
Ox

TRRINO · Feb 29, 2012

Some of the new citizens are able to run" out of the head"
The old cam machines you could do this very easy-it had to do with if you were going to run stock that was out of round. without the guide bushing you could get rounder parts.
With a revolving guide bushing you only can hold 60% of stock roundness.
With a dead guide bushing -they are a little touchy. Can bind up quick.
they make what is called an adaptive guide bushing that opens and closes to run stock that can vary in OD--See CMA = Citizen machinery of America.

TRRINO

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