# Milling with a drill press.



## gadget_lover (Mar 19, 2007)

I came across an interesting article today. It shows an attachment that allows LIGHT milling with a conventional drill press.

The concept is simplicity itself. It attacks the major problem with drill presses , and that's the fact that the bearings are not made to handle loads that come from the side. The spindles are not designed to hold on when side loaded and tend to come loose. This simple attachment simply absorbs the side loading.

The article is at http://warhammer.mcc.virginia.edu/ty/7x10/vault/ShopTools/PM-DP-Mill.pdf

As I understand it, the bearing is a plain bushing, and the "chuck" is an end mill holder with a straight shaft. It looks like the shaft goes through the bushing and into the drill chuck, allowing the drill press to raise and lower the tool as needed.

An X-Y table or machinist's cross-slide vice would be used to move the part you are milling left and right.

I can see where you could do this with the XY table for less than $125. I think you can get a cross-slide vice from Harbor freight for less than $40. I would expect the capacity to be rather light (3/8 inch end mill, perhaps?) 


Just thought I'd throw this out there. I've not tried it, and I don't recommend it. I do like the inovative approach.

Daniel


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## frisco (Mar 19, 2007)

I went down this road 20 years when racing R/C Cars......... Just not a good idea.

Lets just say it would be better than a hand grinder or hand file.

Issues:

- Side load (as you mentioned)
- X-Y vises are sloppy
- The drill press table you clamp the X-Y vise to is not stable. To much leverage against the round column.
- No accurate way to measure cut depth.

frisco


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## will (Mar 19, 2007)

Looking at that set-up does not impress me with the ability to handle side loads. There would be a tremendous amount of torque on a 14 inch drill press. There are only 2 bolts used in a clamping arrangement around a round column. I don't think they would hold that securely.


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## jtice (Mar 19, 2007)

Interesting concept.
I was thinking of setting up my drill press for this a couple years back,
but decided against it, as it seems it would just destroy the bearings.

I could see how that could hold the front to back forces, but not side to side.
Seems you would be able to spin that brace around, being mounted on a round pole.
I suppose you could set it up so you are always milling forward or backwards.

~John


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## will (Mar 19, 2007)

jtice said:


> I could see how that could hold the front to back forces, but not side to side.
> Seems you would be able to spin that brace around, being mounted on a round pole.
> I suppose you could set it up so you are always milling forward or backwards.
> 
> ~John



As part of that - the cutter is going to want to drive the work in the direction of the spin of the cutter.


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## adnj (Mar 19, 2007)

If you are using soft metals and small cuts, the side loads should be reasonable. The distance from the collar bearing to the shaft bearings of the press should be kept to minimum.


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## Anglepoise (Mar 19, 2007)

I don't think it would work well on mine. 

However for simple milling operations similar to what we need for our hobby,
I have been happy with a simple milling attachment, similar but larger than the one shown on this LINK

Gives the extra axis and mine swivels, tilts, and revolves 360°.


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## jtice (Mar 19, 2007)

will said:


> As part of that - the cutter is going to want to drive the work in the direction of the spin of the cutter.


 very very true!


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## ABTOMAT (Mar 19, 2007)

The bearings-destroyed-by-side-load thing is more of a myth than anything else. Drill press bearings (sealed or shielded ball bearings) are the same ones used in motors, grinders, sometimes rollerskates, and a million other things. If anything they're stronger when used with radial loads as opposed to the axial loads.

However, they are _not_ good for milling. They're too small and put in a spindle arrangemnt that can't be adjusted and isn't designed to reduce sideways deflection. That's what real mills use either tapered roller bearings or angular contact bearings. With a drill press you're going to get chatter and broken tools like crazy.

The entire drill press as a whole isn't rigid enough, either. The skinny column, thin table, flexy spindle, and the taper-mounted chuck that may very well fly off and kill someone.

If you plan on milling on a DP, make sure the chuck is a positive-locking type or you're using some kind of replacement milling cutter holder. Keep the tools very small, keep the speeds high, and only work soft metals that don't grab. Like aluminum.


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## gadget_lover (Mar 19, 2007)

will said:


> Looking at that set-up does not impress me with the ability to handle side loads. There would be a tremendous amount of torque on a 14 inch drill press. There are only 2 bolts used in a clamping arrangement around a round column. I don't think they would hold that securely.



It's interesting to see that each of us is envisioning a different drill press. Will's talking about the torque involved with a 14 inch throw, Abtomat is talking about a thin table and skinny column, possibly thinking of a benchtop 8 onch model.

My drill press has a 3 inch column and the whole press weighs around 200 lbs. When everything is locked down it's pretty rigid. The table is cast iron and (with webbing) it is over an inch thick. I can see doing light cuts in soft metal with this setup. You could pin the bearing support arm so it would not shift on the column. 

Ok, time to admit that I actually DID some light cuts with a 1/2 inch end mill on my drill press just to see what would happen. The finish was not great, and I felt silly with the face shield, leather coat, gloves, etc that I wore just in case something came loose. I don't think I would try it again.

On an interesting side note, a neighbor who taught shop class at the high school told me that it was common practice to use endmills in wood to get a flat bottom pocket. 

Daniel
(I'm not advocating the use of a drill press to mill metal)


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## will (Mar 19, 2007)

I do a lot of wood working. A wood lathe uses hand held cutting tools, Using an endmill to cut wood is not a real big deal, wood is significantly easier to work than most metals. 

I have a floor model drill press, 14 inch with a 3 inch column and a heavy duty table. I would not trust the clamping method at all, pinning the arm would probably do it. 

As mentioned elseware - the bearings could be an issue. Most tools that have a side load have fairly large bearings near the tool end. 

For some reason I thought that the bearings in a drill press had top and bottom races as opposed to inner and outer, that is just my feeling, not based on taking anything apart to see.

I worked as a machinist for a number of years, there is a lot of pressure when metal is being milled. I have had stuff come out of a vise while cutting, sometimes even just small cuts. 

My take is that a drill press is a drill press, not a milling machine.


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## scott.cr (Mar 21, 2007)

Interesting read...

My "mill" is a Horror Fright mini-mill... not the micro-mill, but the mini-mill, which is basically a converted drill press. There's not even a fine down-feed on the quill. I know it's not the greatest thing, but heck I can mill steel with it and the price of entry was $220.

The head casting on my mini mill looks EXACTLY like the head casting on the floor-standing drill presses I've seen at Lowe's.


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## gadget_lover (Mar 21, 2007)

Scott, is yours the one with the round post? They are ( I think) re-badged RF (Rong Fu) mills. I almost bought one of those but the price was $600 and I still don't have room for it. 

No fine downfeed? Barbaric!

Daniel


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## scott.cr (Mar 22, 2007)

gadget_lover said:


> No fine downfeed? Barbaric!



LOL! Actually I think the Rong Fu you're thinking of is a bigger, beastlier version of mine, but mine does have a (floppy) round column. At first I was a little afraid to get near this noisy, oil-spitting machine that has all kinds of vibrating sharp edges. With some TLC I got it working decently well; filled the column with concrete, made a fine downfeed, trammed it and cut the table so it was flat... out of the box, the table was wedge shaped to .009". Replaced the drive belt with a Fenner Power Twist, and that was good for a BIG TIME improvement in vibration and surface finish. And I made new drive pulleys on the mini lathe. One of these days I'll add DROs and swap out the AC motor for a DC motor with speed control. To adjust the speed now, I have to jump the belt from pulley to pulley and re-tension with an idler.

So essentially, the mini mill started out as a kit of parts rather than a complete ready-to-use mill... it has been well worth my time in terms of learning imho.


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## Calina (Mar 22, 2007)

gadget_lover said:


> I came across an interesting article today. It shows an attachment that allows LIGHT milling with a conventional drill press.
> 
> The concept is simplicity itself. It attacks the major problem with drill presses , and that's the fact that the bearings are not made to handle loads that come from the side. The spindles are not designed to hold on when side loaded and tend to come loose. This simple attachment simply absorbs the side loading.
> 
> ...


 

The article is dated July 1954. Still, an interestig post.


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## gadget_lover (Mar 23, 2007)

Isn't it neat that the tools developed so far in the past are still relevant?

The 1954 article adresses a basic tool. Like many recent innovations, the changes have come from new electronic controls, better materials and power supplies.

You can find drill presses from the 1800's that employ all the same basic principles as the modern drill press. Some of them are turned by a belt that is driven by wind, water or foot power, but the principles are the same.

I mention this because I have read some very old books and articles about machining. The basic information is still valid. Most of the techniques that worked 50 years ago will work today, especially on the smaller equipment. I find them to be a treasure trove of ideas. They explain how to do things without thousands of dollars in specialty tools.

For instance, I learned about trepanning in a WW II era article. Think of it as boring a hole in a large piece by cutting a deep groove from the end. You are left with a core that can then be used for other projects.

Daniel


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## olephart (Mar 26, 2007)

Sometimes you guys scare me. It's very unsafe to hold a milling cutter in a drill chuck. Well, it's ok if you are going to drill with it. A drill chuck will not continue to hold it's grip on a milling cutter when side loads are applied.

Take another look at that article. The part inserted in the drill chuck has flats at 120 degrees and the cutter is held in place by allen screws.

Can you get away with it for awhile? Sure. Have you ever seen a 1/2" cutter get loose from a drill chuck? I haven't either, but I saw the pictures.

Taking light cuts is not the answer. If the cutter moves down, you ain't taking light cuts anymore. I'm not preaching at you. Just trying to present some information to think about.

I used to do it, too. Then I got some information and thought about it (and saw the photos). I quit doing it 'till I could afford a cheap mill.

Here's a link I just found that seems to address all of the issues. Just put a dot between google and com.

http://groups.googlecom/group/rec.c...53a3f0a15b6/f634cd10ef6ef0da#f634cd10ef6ef0da


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## beemerphile (Mar 26, 2007)

Better it is to drill with a mill than to mill with a drill. Actually better yet it is to drill with a jig grinder. Those who don't care where the hole ends up or how big or round it is are free to use other devices.


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## scott.cr (Mar 28, 2007)

olephart said:


> Sometimes you guys scare me. It's very unsafe to hold a milling cutter in a drill chuck.http://groups.googlecom/group/rec.c...53a3f0a15b6/f634cd10ef6ef0da#f634cd10ef6ef0da



You can still put an end mill holder into a drill press, ASSuming the spindle has a Morse or R8 taper and is bored through for a draw bar.

If the drill press uses a thread-on chuck, an end mill holder could be made from scratch. No big deal. Won't exactly be a quick-change setup though.


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## Anglepoise (Mar 28, 2007)

Unless I am mistaken, most of the hobby drill presses available to us do not have a through hole to secure the Morse taper.
In my case, the interrupted cut produced by milling will loosen the Morse taper#2 drill chuck almost immediately. All to risky.


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