Power Feed for Knee Bridgeport & Clones

[gatz]

Read many threads about buying or making powered Knee Axis for Bridgeports or clones.
I have spent many years moving the knee up and down and up and down at work and as a matter of necessity, had gotten used to it.
But now retired with a DoAll mill at home, I just don't need the aggravation.
Always seems that you need the table UP or DOWN; seldom where it's at, especially when milling the ends of a part, then drilling/reaming

I finally made an adapter to use a Milwaukee Hole Hawg as the power source. I don't think it will fail.

It dawned on me that you don't really need 9 notches in the adapter; just need 3 pins at 120º; 3/16 Dowel pins fit nicely in the slots on the sleeve of the Z axis of the mill. BTW, the Z-axis shaft on the DoAll is 16mm. not 5/8"
The pins are on a .65625R
The end that fits the Milwaukee was bored for a slip fit and keyed 5/16". The stock 1/4-20 LH shcs holds the adapter on.
If anyone wants a drawing, let me know.
It works really well and the low-speed setting on the Hole Hawg seems to be ideal.



Here's a link to it

https://drive.google.com/file/d/1Irs...broNoESDB/view

You can find used Milwaukee Hole Hawgs on eBay occasionally.
Menards also has 5/8" corded drills which should have plenty of power too;
Performax® Corded 5/8" Spade Handle Drill - 7 Amp Model# 2410956 Menards® SKU: 2410956

[DIYer]

Thanks gatz! We've added your Bridgeport Power Feed to our Milling category,
as well as to your builder page: gatz's Homemade Tools. Your receipt:

Bridgeport Power Feed by gatz

tags: mill, power feed

[Ralphxyz]

Your images do not enlarge so kinda hard to see anything! Do you really need 3/4 hp and geared down to operate your table?

I have been "thinking" of doing my Clausing 8520 mill (a smaller mill) but have not figured out what motor to use.

The hp and then the cost of using a Hole Hog makes me wonder.

Ralph

[gatz]

Agreed, the Hole Hawg is a bit overkill, but does the job. I didn't want to start using my Makita 12v cordless drill and burn it out.
A good cordless (say 18 to 20/24 v) should work for your Clausing 8520. Check out the Kobalt drills at Lowes.
And, you'd always have a nice (?) drill around


Sorry about the small pix. I think I just copied and pasted, rather than upload.
These should come in OK

[Ralphxyz]

Thanks, much better with the pictures, A friend just gave me a set of Dewalt i/2" drill and impact driver, cordless. I already had a Makita and Black & Decker
cordless drill and impact driver so I was looking for where to use these Dewalt ones.

Also I have some medical equipment manufacturers DC brushless DC gear motors which I think will work.

How are you controlling the drill? Can you go a set distance or just manually turn it on and get close then adjust by hand?

Thanks for posting.
Ralph

[Toolmaker51]

I fully support powered knee turret mills. Mine isn't yet.
I'd recommend two additions. Counterweight the knee, there are a handful posted here, for reduced motor load, but not such a ratio the knee is 'weightless'.
A low RPM geared DC motor with a variable speed control seems ideal. It really doesn't need much faster than you'd crank by hand. I do know of one instance a corded 1/2" Milwaukee in the hands of an aggressive apprentice wore out the lead screw nut trying to achieve escape velocity.
Anyway; my interest is to broaden the feed rate per spindle revolution [typ .0015, .003, & .006]. This increases tool radius selection, desired surface finish on varied materials. Also allows the spindle remain fully retracted and locked for an extra bit of rigidity.

https://www.homemadetools.net/forum/...archid=1530489

[Ralphxyz]

I wonder how accurately you can position the table? Using a drill or even a geared DC motor? Do you still need the hand wheel to set the table
or just roughly move the table and set you depth of cut with the spindle?

Ralph

[Crusty]

A buddy had a 39' sailboat that he often sailed single handed and the genoa headsail on that boat was a huge thing that really took two men to handle but he rigged up a Milwaukee power wrench so that he could use it for hoisting and trimming that sail on his self tailing winches and it worked, though the batteries didn't last all that long due to the biggish torque required. I'm thinking one of those might be a viable solution for my mini knee mill because cranking it up and down has really become a pain to me.

[Toolmaker51]

I wonder how accurately you can position the table? Using a drill or even a geared DC motor? Do you still need the hand wheel to set the table
or just roughly move the table and set you depth of cut with the spindle?

Ralph

Some kind of clutch or disengagement would be needed to operate manually if the drive is wormed, maybe even hypoid. Long as dial or readout is present, a low speed could be parked very close to the desired setting. I've got one big ol' spoked cast iron steering wheel [likely a farm tractor], a 50's style spinner knob waiting for 'just-right' drive motor. Tony Foale used gas springs connected to machine base and knee instead of counterweight. I have lots of rotary tables, indexers, fixtures etc; heavy stuff making adjustable counterweight worthwhile. An arm, a sliding weight or some chain and can full of lead.
Since no shop I've worked EVER had a designated 'cranker-dude'. Seems odd though, since he's mentioned frequently. . .

[Crusty]

He's busy sweeping up swarf - no time for crankin'.