$99 Mill

[riko]

I had an idea for a drill press to mill conversion.

Having read the fine machine build by ZipSnipe:
My Manual small mill project
the costs for fabricating the mill are pretty high compared to just buying an X3 mill.

I own the same XY table (Shars http://www.shars.com/products/view/3...mp_Drill_Table)
for $99) and use it for XY drill work but would like to do a little milling with it.


I had an idea for a cheapo way to use the benchtop drill press for milling without torturing the quill assembly and bearings.

The idea is to mount the XY table on the bottom plate of the drill press, bolt a mounted bearing pillow block to the drill table and then turn the table upside down.

All that is needed is a long shaft to couple the drill press drive to a straight shank collet mounted in the pillow block bearing.

The benefits are:

1. the pillow block bearing takes all the side loads for milling.
2. the table is pretty low on the column to reduce deflection
of the round column.
3. The weight of the table should reduce vibrations.

I have an old Central Machinery bench drill press to try this out.

Will post a few pictures of the idea.

[draughted]

when entering this field thought of the drill press as cheap solution
i soon figured the most it could be was a $50 x/y cross sliding vice that can be used in conjuction with a fly cutter mounted in the MT2 spindle, thats used for facing off material

you would be better off constructing an entire z axis and spindle mount for a proper cnc machine

[riko]

Going to try the inverted table out just to see what can be done in a sort of bootstrap effort.

I noticed a lot of designs for a vertical mill are done by someone with access to
a machine shop (day job) or in one case by buying a dovetail slide.

I have some steel stock laying around.

Here is what I have :

1. 2.5" 3/16" Square tubing (maybe 20 feet)
2. steel angle 2.5" 1/4" wall
3. 1" sqaure steel bar (20 feet)
4" 12mm stainless steel threaded rod
5. 1/2" and 3/4" keyed shafting

Looking to get that steel off of my palet rack and put it to use.

Equipment is:

0. Heavy duty 12 speed drill press
1. Shar's XY milling table (6"x 12" travel)
2. Horizontal bandsaw
3. Stick Welder
4. Acetylene torch
5. digital calipers
6. small flat stock manual bending arm

In short, what you would normally see in a shop without a mill or lathe.

Power drive is a motor from a broken compressor.

My first thought for a Z axis design as you suggest is to do a Taig type of design.

I like the idea of the mill being lightweight and easy to disassemble and move.

I know that the tubing is not as great a cross section as other designs but it's what I have.

I think I might like to do just as Taig has (ie single column) and then test the machine.

Then maybe add a second tube behind it welded together to see the difference.

I'm looking for suggestions for a box way design from the square bar.

As far as the spindle I wanted try out the mounted bearins on my drill press idea to see how well they perform. I have a boxful of 3/4" spherical adjustable bearings around.

My goal is to stay under budget (otherwise buying a taig is a cheaper way to go) and use what I already have around. My goal is light milling and precison drilling.

Looking for some ideas on box ways for the square tube using the 1" bar.

I have akready been able to face mill the bar stick with the quill locked. I was even able to use a flat sharpened drill bit as a poor man's end mill.

Again it is a bit of a learning excercise to see what can be done to bootstrap a mill (without cheating by buying one in whaich case I would't need to make one).

I have priced out a straight shaft collet with various size inserts for $50 on ebay and that is about all I'm prepared to spend.additionally (there is a recession on still you know).

How about it, any junkyard engineer's out there?

Anybody that did a Enco (Shar's) milling table design already is extra welcome.

[riko]

Here is a link to Taig assembly: http://www.super-tech.com/root/itm.a...aig-Mill-Parts
And the box ways on Taig: http://thehobbyistmachineshop.com/Taig/DSC04212.jpg

Should I buy the ways or try to make a version. Both parts are $31.

Here is a shot of milling I did picture of 1/2" block using a flat (actually a little inverted profile) 1/2" drill bit

I am thinking to do this in four steps:

1. get the milling working on my drill press (which is working OK right now for the locked quill, but will try the inverted table and extra bearing support).
2. Use the taig plans and the drill press milling (mainly for the steel way welded and machined support attached to the column) to build a light duty machine.
3. once that is working see if adding an extra welded column to the back helps.
4. USe the light duty machine to do parts for a heavier model with 4 welded columns in a square configuration. I have a 24"x24"x1/2" steel plate (pitted and rusted but will work) to add side columns to the tube.

Anybody work with FEA software? I haveIronCad and Cosmos FEA limited node edition which can analyze deflections (and animate).

I want to do the light duty version so this doesn't stay a paper design only.

I will post all drawings of my Taig look-alike.

[will gilmore]

lets see some pictures of this machine in progress. i'm always interested in low buck stuff.

[riko]

Well, here's the low buck upside down drill press.

The drill I have is actually a Continental (taiwan) 1/2 HP.

Pretty heavy as bench drill presses go I guess. I mounted a 1/2" spherically adjustable (swivels every which way to take up mis-alignment) to a piece of channel and bolted to the drill press table. Not pretty but I just wanted to see if it was better than milling using the locked quill. The XY table didn't fit the base so I used two bolts and a clamp.

I originally tried to grind a cutter from a 1/2" shaft and then heat treat, but it wore out quickly. It is only 1045 vs. 1095 for drill rod so it may not have enough carbon. i have a batch of superquench I may try to see if it can get a higher rockwell.

But for now I just made a coupler by reaming a small threaded coupler and used a flat sharpened drill bit that I used when I milled from the quill.

I set the drill press at a fairly low RPM (350) to see how rigid this method was.

You can see the results in the video (millDrill.zip). Quite a bit more force available this way. The weight of the table helps and the bearing has a cast mount with a heavy walled outer race.

I have a smaller bench drill press I want to try just for laughs and grins before I start building the Taig clone.

I'll have to look around to see if I have some drill rod.

Should I work on some drawings for the Taig lookalike (maybe I'll call it the Schmaig after the Shars $99 XY table) or just start butchering up some angle and tubing and have it with the welder.

[riko]

I may weld up a special attachment to hold two of the mounted bearings back to back and preload them. They have a lot of axial play but this is good because they can act in an angular contact fashion. The bearing raceways are pretty deep on these types of bearings.

The attachment would replace the table and attach to the table crank handle casting.

With two bearings separated and pre-loaded I can get rid of axial play. And then maybe use a lovejoy coupler to go from the drill press 1/2" chucked shaft downto an straight shank endmill holder (collet)

Here's the endmill holder I want to get eventually:
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT
1/2" straight shank x 5"

Or maybe this one 3/4" is better:
http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWAX:IT


And then an actual endmill: http://cgi.ebay.com/USA-MONSTER-1-2-...DLVI%26ps%3D54

[riko]

Came up with another approach. I found out I could put the insert bearings right into the squeeze holder for the table (bearings top and bottom).

So I jettisoned the table and used a lovejoy two piece shaft coupler and the 1/2" shaft to drive it.

You can pre-load one bearing against the other to eliminate axial play using the set screws on the inner races of the insert bearings.

Attached are some pictures of the machine and some test cuts in steel.

I gradually increased the depth of cut in steel once I saw it was milling OK.

The last cut was about .07" x 1/2".

The shaft on the drill press table measure 47mm. I think there are some real angular contact bearings with that OD I could put in there if the raceways were thick enough like the insert bearings to take the squeeze lever force.

If I could figure out how to rig up a boring bar I could make an actual spindle.

The insert bearings are about $2 each so I guess I'm over the original budget of the $99 mill. $103 mill?

Shars + Drill Press = ShMill

[will gilmore]

nice work. can you move the z?

[riko]

I had thought of a couple of options for that:

1. If I had a Steel spindle sleeve with a 47mm OD then I could leave the squeeze clamp on the table mount a little loose so the drill press quill could move the whole spindle assembly up and down. Kind of like another quill but one you can take all the play out of.

2. With the bearings squeezed the way they are now I could leave he clamp on the column a little loose and then use the crank handle on the columnto move it up and down. I would need something to prevent the cast table support (with the bearings in it) from rotating around the column.

There is the gear rack which i could put a gib up against, but the gear rack is not in any kind of groove an can rotate itself around the column.

I could machine up some square stock and add a slide to the other side of the column and put a groove in the cast column piece or make the slide external. Looking for any easy way to attach.

I have some 1" x 1" bar stock which would be fairly strong.

3. I could make a replacement for the cast piece which has a slide on it. The cast support arm unbolts from the cast piece with the crank handle on it.

Looking for an easy way to do this.

[riko]

I can get either angular contact roller bearings or tapered, cone type of roller bearings.

What does a regular store bought spindle usually have?

I would think the tapered style are better.

The inside of the table support is looks pretty accurate (machine seat on top and bottom).

I could also do a sleeve spacer top and bottom to keep the outer rings in place.

I saw some at the local TSC (Tractor Supply Co) outlet.

[2_many_hobbies]

Hey I thought I would throw an idea on how you can get a moving z-axis.

I was browsing sdp-si.com and saw some pinion wire stock and thought if you could broach a cylinder with splines and have a round key inside that would allow power transmission but also allow you to adjust height a few inches.

You would need to brace your holding arm so when you crank it up the drill presses table adjuster it remains strait but that's the easy part.