# Z axis (knee) power feed recomendations



## alloy

I have a Kent 4VK mill that's about 3200lbs.  About the size of a series II Bridgeport and am looking at a power feed for the knee.   Sales have been good lately and I'm tired of cranking that heavy knee up and down all the time.  I would rather work smarter than harder any day as I spend a lot of time lately on my mill.

A Servo brand is out of the question at $1200 so that leaves import brands.  I've read a lot about them and have seen quotes that they are just as good as the Servo brand feeds.  But I don't know the people that posted that and wanted to ask here where I trust people to help me spend my hard earned money. 

The knee is pretty heavy and all I've seen are 150lb torque feeds.  I'm not sure id there are 200lb ones or not.

I welcome your comments.

Was looking at this one on Ebay.

http://www.ebay.com/itm/Power-Feed-...474773?hash=item1eb3dab915:g:0xQAAOSwCEdYUBzo


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## Holescreek

I make my own version of this drill adapter for my mills and use a 1/2" corded hand drill to spin it.  If I'm just drilling I leave it set up and raise and lower the table as needed. If I'm milling I slip it off and put the handle on for fine adjustments.  I've made the adapters for other style mills for a friend, it's just the concept of using a drill to do the hard work.

http://www.ebay.com/itm/Bridgeport-...754398?hash=item1a23eb049e:g:jHQAAOSwopRYfYSU


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## Rick_B

I've got one of the adapters that holescreek showed (not sure if it is his or not).  It works great and is a reasonable alternative to a power feed - in my opinin
Rick


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## Terry Lingle

I made a power feed  for my mill from  a 1/2 inch electric drill and a couple of chain sprockets to reduce the speed by a factor of two.
it is hard mounted with the drill  back along the "tube that the raise shaft runs in. I made an extension for the hand crank so I could use it for fine adjustments. 
Caution if you do this be sure to remove the hand crank from the operating position when you are not using it.
The drill trigger was replaced with a remote forward- off-reverse switch and a dimmer used as a speed control.
Before I started fabricating I tested using the drill to drive the table raise /lower directly  and found that it would overload and try to release the magic smoke at low speeds.. The drill is a Milwaukee 1/2 inch 800 rpm model IIRC and with the 2:1 reduction it is not overpowered.


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## talvare

I made one for my BP a few years ago. Purchased a gear head motor, sprockets and chain on eBay and fabricated the rest of the pieces. I made it with an adjustable clutch so that it can be set so that nothing gets damaged if I get stupid and run the knee too far in either direction. Also, the clutch can be completely released with about 1/4 turn of the hub (shown in the photo with the handle in one of the holes) and the knee can be operated manually with a 1" socket and ratchet. It works very well and I think I've got less than $100 invested.





Ted


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## Holescreek

How do you make fine adjustments for milling with power feed units?   I haven't seen one that has an extension shaft for the crank handle.


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## Terry Lingle

on mine I machined an extention drive  that has the driven sprocket melded onto it  the regular crank handle fits onto the extension the same as it used to fit on the knee drive just be sure to remove it before you use the power drive. I have a chain gaurd on mine so it is a little complicated to get a picture of the drive extension but I will take a couple of pictures  of it with the original drive handle in place.


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## Holescreek

A 6" vise is overkill for a RF45 style mill. A 4" is more appropiate for that size mill & IMO 5" max. I have a 5" GMT vise on my PM45 & it's slightly too big. Not enough Y axis travel to make use of the 5" full capacity. Better to save your money rather than getting something too big & most importantly the weight. I take my vise of the table quite often, a 6" is still light enough for me to be carried by hand but I'm glad I have a 5". I also have a 4" vise as well. I prefer the 5" though.

But those GMT 6" Premium vises are pretty nice. I'd love to have one but don't need one on my current mill. But if you plan on upgrading to a full size knee mill in the future than the 6" will be perfect.


Here's what the 5" looks like on my mill.




I couldn't even complete this cut without my bellows & DRO scale getting in the way. Not enough Y travel & the 5" vise is not even maxed out.




Here's what a 6" vise looks like on another PM45 (gt40's)
View attachment 253544


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## alloy

I picked up one of those adapters.  Its for sale cheap now. Only used once. 

My Milwaukee fuel 1/2" drill doesn't have enough power to lift the knee.


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## Kroll

Like the adapter ideal,if you can find one of those older American made Milwaukee Angle Drills I bet it will have enough torque to raise/lower the knee.Plumbers would use these drills with screw type wood bits to punch holes for pipes.And it being angle drill it would not stick out as far as the other drill.Just another ideal----kroll


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## mksj

I would look at the Align power feeds, I have two on my mill and they work very well. They are made in Taiwan and I find things like the switches and body to be more solid than some of the cheaper modes I have seen. They are less than 1/3 the price of the servo, and I have found them very well made and have had no issues. You might check prices with some of the milling machine importers like Kent, Acra , etc. or some of the distributors like Penn Tools as to models and specifics.
http://www.penntoolco.com/al-500pz
http://www.align.com.tw/manuals-en/powerfeed/


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## alloy

No one that I can find has an import type 200 power feed clone for the knee. A 150
isn't powerful enough. 

Before i sold my Bridgeport I had the Kent sitting beside it and it made the Bridgeport look like a 1/2 size machine.


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## JimDawson

Wait till you crank that Shizuoka knee up, I cranked it up about 8 inches and had to take a break halfway through.    We might want to design a power feed for it.

The specs on that Align look much like the Servo 200, but ya never know.


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## mksj

As Jim mentioned, the Align 500PZ states higher continuous and maximum torque rating then the Servo 200. Alternate would be to use something like a Bodine gear motor with a belt drive or possibly a 90 degree drive. I have done this with their 3 Phase gear motors with a VFD and it was pretty much unstoppable on a Z drive. 
Align Power Feed Torque: 
Continuous 150 in-lb, Max 650 in-lb

Servo 200 Power Feed Torque: 
Peak Torque 200 in.- lb. / 22.6 NM torque
Intermittent Torque: 150 in.- lb. / 17.0 NM
Continuous Torque: 120 in.- lb. / 13.0 NM


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## MtnBiker

mksj said:


> As Jim mentioned, the Align 500PZ states higher continuous and maximum torque rating then the Servo 200. Alternate would be to use something like a Bodine gear motor with a belt drive or possibly a 90 degree drive. I have done this with their 3 Phase gear motors with a VFD and it was pretty much unstoppable on a Z drive.
> Align Power Feed Torque:
> Continuous 150 in-lb, Max 650 in-lb
> 
> Servo 200 Power Feed Torque:
> Peak Torque 200 in.- lb. / 22.6 NM torque
> Intermittent Torque: 150 in.- lb. / 17.0 NM
> Continuous Torque: 120 in.- lb. / 13.0 NM


The Align AL500P (780 lbs./inch max) lifts my knee just fine. I have a PM1054 so a heavy knee and table.


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## Tim9

alloy said:


> *A 6" vise is overkill for a RF45 style mill. A 4" is more appropiate for that size mill & IMO 5" max. I have a 5" GMT vise on my PM45 & it's slightly too big.*
> I picked up one of those adapters.  Its for sale cheap now. Only used once.
> 
> My Milwaukee fuel 1/2" drill doesn't have enough power to lift the knee.


Holescreek is absolutely correct. I purchased a very nice older Japanese 5” milling vise. It’s too big in my opinion. I had my Millrite in storage and was using a RF45 clone. So I figured I’d get a 5” and then when I finally got my Millrite working.... then the 5” would be perfect.
Granted, my Millrite is the smaller table but the 5” is a big vise in my opinion. A 4” is perfect.
on another note, I then purchased a Shars 4” for the RF45. It’s okay. But when I was able to find a Kurt 4” on EBay....man I have to tell you. There is absolutely no comparison to the Chinese angle locks and a Kurt. The Chinese feels spongy. The Kurt is rock solid. I really like the Kurt and regret buying the Shars.
  I really need to sell some crap I’m not using. And that includes the 4” vise sitting on the ground.


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## hman

I just bought a new PM knee mill.  As just about everybody else has discovered, cranking the knee up and down (160 turns for 16" travel) is a real PITA.  I know there are drill motor adapters for sale out there, or I could have made my own on a rotary table.  But the 9 wedge-like segment cuts would have required me to figure out a bunch of setups, etc.

So I decided to push on the "Easy" button and bang out something simple ... drill & tap a circle of 9 holes, screw in some 8-32 socket head cap screws, and bore out the center - one end to clear the mill's crank shaft and the other end for a 1/2" shaft to go into the drill.

Then, just for fun, I added a timing belt pulley I had in one of my dusty drawers.  Rounded the ends of the teeth a bit for comfort, and now I have a way to manually fine-tune the Z position without needing to take off the drill motor, slip on the big crank, etc.  Obviously, it won't work for very heavy loads on the mill table.  But it'll be just fine for most of what I plan to do on the mill.

PS - the knurling is a just a leftover artifact that was already on the aluminum rod I started with.


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## dhprecision

All very good ideas. Once my BP arrives it looks like I have a new project to add to the list. Thanks


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