mill size limited by speed?

[rogee]

I am looking at a number of Chi-com milling machines that have their slowest speed setting at the 230-270rpm range. The mills in question are in the $3500 and up price range, not high end units, but certainly not cheap for a hobby shop purchase. It seems to me that this high rpm for the slowest speed would be very limiting on what you could do with one of these machines? Am I right, or am I just being overly pessimistic, given that they all are set up with R-8 collets? I have looked for older American Iron, for some time, without good results.

 

[Tony Wells]

Just an opinion, but I believe they realize that their customers won't be using 3/4" end mills or larger milling cutters where you might want slower speeds. The mills may not handle the stress, or take the cut. Or on the other hand, they may be counting on all carbide, where there is more need for speed than low end torque.

 

[Ray C]

Lower speeds really come in hand for power reaming and for some face cutters. You might want to check-out these mills as all of them have decent speed ranges. I can't say enough about the products from this place...

http://www.machinetoolonline.com/Newmillindex.html


Ray

I am looking at a number of Chi-com milling machines that have their slowest speed setting at the 230-270rpm range. The mills in question are in the $3500 and up price range, not high end units, but certainly not cheap for a hobby shop purchase. It seems to me that this high rpm for the slowest speed would be very limiting on what you could do with one of these machines? Am I right, or am I just being overly pessimistic, given that they all are set up with R-8 collets? I have looked for older American Iron, for some time, without good results.

 

[Ray C]

rogee,

You've got me curious... What manual machines are out there these days costing 3500 bucks and do not have sane speed ranges? Call me old fashioned but a machine that doesn't have decent slow speeds is a bit more useless than one without decent top-end speeds...

What kind of milling and projects are you thinking about?


Ray

I am looking at a number of Chi-com milling machines that have their slowest speed setting at the 230-270rpm range. The mills in question are in the $3500 and up price range, not high end units, but certainly not cheap for a hobby shop purchase. It seems to me that this high rpm for the slowest speed would be very limiting on what you could do with one of these machines? Am I right, or am I just being overly pessimistic, given that they all are set up with R-8 collets? I have looked for older American Iron, for some time, without good results.

 

[rogee]

Ray

Thanks for your interest in my post, I really didn't want to get into zinging a particular brand. However, the machine I was interested in is the Grizzly model G0729 This machine comes from Taiwan, so I am hoping that it would be a set up from its Central machine cousins. The speed rang is 230-2520 in 9 steps. The reason I was interested in this particular machine was I read that it was more or less a copy of the Causing 8520 mill that has interested me for a long time. Anyone with experience with this mill?

 

[Ray C]

It wasn't my intention at all to bash someone's product. I don't go there. What is the speed range on the Central Machine version? I'm seriously thinking misprint. Give Griz a call.


What's the speed range of the original Clausing?

Ray

Thanks for your interest in my post, I really didn't want to get into zinging a particular brand. However, the machine I was interested in is the Grizzly model G0729 This machine comes from Taiwan, so I am hoping that it would be a set up from its Central machine cousins. The speed rang is 230-2520 in 9 steps. The reason I was interested in this particular machine was I read that it was more or less a copy of the Causing 8520 mill that has interested me for a long time. Anyone with experience with this mill?

 

[brasssmanget]

For what it's worth, my old(er) RF-31 bench top can slow down to 125rpm - that's a Taiwanese machine. Not even near the $3500. tag when I bought it, or even now I suspect, so................

I'm guessing you are talking about full size mills.....

 

[Ray C]

I think it's possible we're not making fair comparisons here. Before all else, look at the overall construction of the machine and decide what purpose it's intended to serve. There are many applications calling mainly for drilling and heavy stock removal -and maybe that's the intended purpose of the machine. Without serious cash outlay, there are few machines that can do everything from micro-surgery to major hogging... In a home-shop environment, micro-surgery to medium removal is the sweet spot. You can still remove stock but it needs to be done with patience. I for one try to start-out with appropriately sized pieces and that means cutting things down in the bandsaw or other means first. Also, I regard slower speeds as pretty important, mainly for reaming, counter sinking etc. In my experiences, use of the bottom-end speed is greater than the use of the top-end speed.

Another thing that gives me a chuckle... I've seen so many you tube videos of folks take lightweight mills, loading them up with a 5/8 cutter and (attempt to) plow through a cube of 4140 at full depth. Somehow, the machine survives... -Remind me to never buy that guy's used machinery...

I guess the point is to use a machine within it's intended purpose...

Ray

 

[Pacer]

That mill is generically called the "6x26" you might do research using that term to get more info on it. there is a yahoo group: http://finance.groups.yahoo.com/group/6x26millingmachines/ There arent usually to many complaints on the speed range (tho it is an irritation) the biggie problems with it is in the spindle to table and spindle to column dims (12 1/4" and 6 1/2"). When you get a vise mounted and a collet/drillchuck/cutter etc mounted the work space is very small and the Y travel runs out very quickly. I had this mill from Wholesale tool and it introduced me to using a knee - which forever spoiled me - and I really liked the mill ...except for those 2 glaring probs. Many guys add a spacer to the column (I did) which really eases the work envelope. As I mentioned, WT carries this mill and KBC did also - there is also (was?) an 8x30 version offered by KBC and maybe Grizz too? which should really ease the space/travel probs. Personally if I was just starting out now I'd go with one of the X45 types.