Help Choosing New Mill!

[Dan_S]

. But then I am crazy like Coolidge...

.
My plan has you both beat. Once the wedding is over, and I finally get a new job, the 940 will either get cnc'd or become a second op machine, and the main machine will be either pm 10x54, or a sharp TMV. Same things going to happen with the lathes.

 

[coolidge]

.
My plan has you both beat. Once the wedding is over, and I finally get a new job, the 940 will either get cnc'd or become a second op machine, and the main machine will be either pm 10x54, or a sharp TMV. Same things going to happen with the lathes.

Ahahaha get some!

 

[wrmiller]

wrt to the 12Z, coolidge used to have one and gave it away and now he has the 935TV....

Really? Wow... Having talked to Charles about why he decided to not keep the 12z and just leap up to the PM935, I'd love to hear your take on this and what you are inferring. Actually, never mind.

 

[mksj]

Didn't know that there was a baby knee mill smaller than the 935, but QMT has a PM-836S which may be worth looking at. When you consider the price includes clamp set, R8 collets, a 4" vise and is delivered, it puts it very close to the 932-940 price range. Get a small Teco VFD for about $150, and you will have a very nice mill. I always regret not going to a knee style mill from the start. Previous post with another individual upgrading from a PM-25, and was looking at the PM450 or 836. If tight on a budget, PM450G would be my first choice at $3K, otherwise a baby knee. Worth thinking about what you want to do and have a discussion with Matt, might be able to swing something for you before the year end. I am saving my pennies to try to upgrade to a knee sometime next year, just do not have the rigidity I want in my bench top mill.

http://www.hobby-machinist.com/threads/pm836s-pm450g.36559/

http://www.ebay.com/itm/PM-836S-8x3...133434?hash=item35f7a63c3a:g:hhgAAMXQlgtTBAiX

 

[JR49]

the 935 is a nice choice, and a knee mill is much more useful than a square column mill

Just curious, why is a knee mill more usefull than a square column? please don't think I'm trying to disagree with your statement. Fact is, I've not yet even used a mill, so just trying to learn. Thanks, JR49

 

[planeflyer21]

Just curious, why is a knee mill more usefull than a square column? please don't think I'm trying to disagree with your statement. Fact is, I've not yet even used a mill, so just trying to learn. Thanks, JR49

I wouldn't necessarily say more "useful" but perhaps more "versatile".

Because of this:

Not only can the head rotate but it can swivel and extend in and out, allowing one to cut more compound angles and bores.

 

[tmarks11]

A knee tends to be more precise in positioning than the head on a square column. Beefier, more spread to the load means that it doesn't tend to sag as much as the head on a square column mill. Makes it easier to get a precise z-height change. That doesn't mean that you can't get just as precise cuts on a square column, just that it is easier on a knee.

The flip side is that a knee mill weighs twice as much... at least.

.. I'd love to hear your take on this and what you are inferring. Actually, never mind.

My post was innocuous; read it again. Any inferring is being done by you. Coolidge had the 12Z and now he has a 935. But I have read more "I like my mill" stories about the PM variants than the CO (or IH) variants.

 

[coolidge]

Deleted

 

[Dan_S]

I guess these mills used to have some kind of milling attachment on the back of them so you could swing it around to use that. Realistically I think swinging it left to right within the table/work cube is probably all you would ever use.

Bridgeport, made a bunch of special heads, shaper, right angle, horizontal, & a cherrying head.
http://www.lathes.co.uk/bridgeport/page4.html

There's more, this style mill has a power down feed which most square column bench mills do not have. You have 3 different speeds, I'm told this is mostly used for boring. I believe you can setup auto stops and retracts.

The better larger bed mills like the pm-940, pm-932, pm-945 have this as well.

 

[JimDawson]

This Bridgeport style head knee mill has a few more features. The entire head/motor/spindle is on a ram you can crank forward and back several inches. If you are machining a larger odd shaped part you can reach out further or retract back towards the column as needed. A square column bench top mill is fixed and does not move. Further the entire head/ram can swing 360 degrees around on a turret. I guess these mills used to have some kind of milling attachment on the back of them so you could swing it around to use that. Realistically I think swinging it left to right within the table/work cube is probably all you would ever use. Next as someone else mentioned the head not only tilts left and right but nods forward and back.

There's more, this style mill has a power down feed which most square column bench mills do not have. You have 3 different speeds, I'm told this is mostly used for boring. I believe you can setup auto stops and retracts. In this style mill the head once locked in place does not move, instead the knee moves up and down. Having used both style mills my opinion is its easier to get the knee style head dialed in square and true and keep it there since it never moves.

:+1: