# my latest mill attach ($65) handmade



## SE18 (Mar 1, 2013)

Here’s my latest mill attachment for my South Bend 9A lathe. My first one was exactly like this but made using wood, as a mockup (it actually worked on wood and soft metal).</SPAN>

My intent is to make do with this until a decent mill can be afforded, rather than buy or make a pricey mill attachment that is half the cost of a real mill. Since I’ll be furlowed soon by Uncle Sam, it may be a long time before I can afford a nice Bridgeport Mill.</SPAN>

Original plan was to make the face plate T-slotted, but just decided would be quicker to do it this way. Actually got lazy to be honest.</SPAN>

Bottom plate and side plate are ¾” hot rolled. Since I don’t have a bandsaw, I cut them on my table saw with a 10” fibre cutoff wheel. I hit both sides so ended up with a ridge in the middle where it didn’t line up.  The table saw can actually cut steel faster than a bandsaw and the wheels are just 3 bucks.</SPAN>

The scrap steel in the pictures is from carving up the plate, and I tested a ¾” end mill on it to clean up the edge using climbing cuts and non-climbing cuts. Feed depth was .005 and cuts were interrupted.</SPAN>

All 20 holes on the side plate and all 3 holes (including the one holding the 60 degree taper button that fits into the crossslide, are 1/2X13, drilled out with a 29/64 bit that is 135 angle and tapped. The tapping was hard so I used an old fashioned handle from a car scissor jack to assist. Tap was backed in and out and cool tool lubricant. My biggest fear was breaking the tap, but it held, as it is American made.</SPAN>

The side plate is 7” X 7”, and the angle plate is 6” X 6”. Angle plate got off Amazon for $20 not including shipping.  The steel for the side and bottom plates was $20 from a metal dealer in Elk Ridge MD. The button (not photo’d) was turned from CR1018 1.75” diameter, from nearby BMG metal shop in Manassas VA. I purchased 12 feet of it so I have several buttons, a test bar and a lot left to play around with.</SPAN>

Oh, and the vise is 4” and was $20 from TSC.</SPAN>

The advantage of having all bolts the same ½-13 is that they all can be adjusted with my ¾” box wrench</SPAN>

The vise could be held by 4 bolts but I found that 2 suffice.</SPAN>

The side plate is held to the angle plate by just one bolt (1/2-13 of course). I was pleasantly surprised that it held so well. And what’s cool about using just one bolt is you can tilt it 360 degrees (the mill attachment can also be swiveled 360 degrees on the crossslide).</SPAN>

I don’t have any collets or end mill holders so I wrap each end mill in one layer of brown paper and chuck it. My biggest fear was the end mill would spin off, as I’ve had drill bits spin in my tail stock chuck. Again, I was pleasantly surprised b/c the cuts you take on this sort of fixture will never be deep so there’s less trauma there.</SPAN>

My first test was disappointing somewhat. It went thru wood and soft metal like butter but steel gave it problems. Specifically, it forced the entire attachment to spin around on the button that is attaching it to the crossslide. The force was so strong, it completely loosened the set screws that hold the button in the crosslide.</SPAN>

So I rechecked the button angle and it was 60 degrees and measured exactly like my compound button.</SPAN>

This would have been a show stopper for steel. I’d been using a hex key to tighten the set screws so I just got back from Lowes with a 3/8” socket hex for the 3/16 hex. This did 2 things. Since South Bend 9A made in 1942 put the set screws in the back of the crossslide, the extended reach of the hex drive made the miserable task of reaching around back under the mill attachment so, so , so much easier. Secondly, the ball hex wrench (in photo), allowed me to tighten the hex even more and this stopped the spinning of the mill attachment.</SPAN>

Once everything was secured, my 2[SUP]nd</SPAN>[/SUP] attempt actually worked and the steel was milled. Milling on a lathe is a pretty violent thing. Despite everything, you could see the thing groaning and nearly vibrating. I also locked down the carriage and unlocked and locked it with each pass.</SPAN>

Had one hand on the feed and the other on the off switch (I should make a foot kill switch). One improvement I may make would be to prop a block of wood under the attachment and resting on the ways like I’ve seen in pictures in popular mechanics. But with light cuts on steel and deep cuts on wood and soft metal, that’s not a must have.</SPAN>

So right away, you notice in the photos that there’s a problem with the Z axis as I did not build a screw to move it up and down. However, the vise can actually be moved way down and way up and down even below the crossslide using the holes on the side plate which line up with the 2 slots on the vise.</SPAN>

The Y axis is probably the most limiting aspect as you only get 6” of travel via the crosslide. The remedy is to simply turn the work around if it is really long.</SPAN>

The X axis is actually more advantageous than every mill except for the biggest ones, according to some experts, due to the greater length of a lathe. My lathe has a 42” bed (actually around 23 or so inches of real length).</SPAN>

My next project will be researching work-holding devices or simply playing around and making some myself with scraps of steel.</SPAN>

The mill attachment will mostly be used for making hobby train parts for my 1:13.7 scale trains I build. If you're every near Manassas VA stop by and you can see the mill and other things
daveV</SPAN>


----------



## kacce (Mar 2, 2013)

Very nice  mill attachment


this will be my next project
When I'm done with MyFord saw


----------



## Halligan142 (Mar 2, 2013)

I can't really tell from the pics but there are 2 tapped holes in the crosslide that you can use to make that attachment extra secure and keep it from swinging.  Figure out the arc the bolts would make on the attachment and you can drill multiple holes to hold it at convenient anges to the spindle.  Nice job by the way.   I just picked up a Palmgren 250 on the cheap and am figuring out a nice base for it.  Also be carful with your endmills.  The cheapies (that dreaded HF set and ones like it) kinda suck on anything but wood and aluminum and makes cutting steel a PITA.


----------



## SE18 (Mar 2, 2013)

Thanks

There are no other holding devices than the button that goes into the crossslide, which is held in place by the 2 set screws you see, which push a tapered pin up against the button

Should I drill some holes in the crosslide? Has anyone done this?

Incidentally, I had a lot of fun with the mill today. Only once did it spin around when I took too deep a cut at .01

Dave


----------



## kacce (Mar 2, 2013)

Here are two original holes on my sb9.


----------



## Halligan142 (Mar 2, 2013)

Hrm.... Thought they all had that.  Maybe because of the difference in years?  Her's mine.  It was made in 1950




Also have a look here :  http://www.wswells.com/data/howto/robert_lang/ATT_7.pdf


----------



## kacce (Mar 2, 2013)

My lahte have nr 50784nax  1962- 63
[h=1][/h][h=1][/h][h=1][/h]


----------



## SE18 (Mar 2, 2013)

1942 no lathe had them. I wonder what size and thread and location they're in? I'd hate to put them in the wrong place. I'd also have to take my mill apart or drill thru the 3/4" bottom plate and then thru the 1/2" angle plate to get a screw in there. I'm thinking I have to remove the crossslide from apron. I'm guessing they're cast iron so no lubricant is necessary when drilling. What a PITA! No wonder it was spinning on me!!!!!!

So once the holes and screws are there, that would preclude putting the mill attachment at an angle other than straight. Truing up the holes on the mill attachment would be difficult I imagine. If they're off just a hair, then the work would not be 90 degrees to the headstock


----------



## Halligan142 (Mar 2, 2013)

SE18 said:


> 1942 no lathe had them. I wonder what size and thread and location they're in? I'd hate to put them in the wrong place. I'd also have to take my mill apart or drill thru the 3/4" bottom plate and then thru the 1/2" angle plate to get a screw in there. I'm thinking I have to remove the crossslide from apron. I'm guessing they're cast iron so no lubricant is necessary when drilling. What a PITA! No wonder it was spinning on me!!!!!!
> 
> So once the holes and screws are there, that would preclude putting the mill attachment at an angle other than straight. Truing up the holes on the mill attachment would be difficult I imagine. If they're off just a hair, then the work would not be 90 degrees to the headstock



Doesn't necessarily have to be that snug a fit.  As you can see by the PDF the SB attachment was slotted in an arc to allow the entire unit to be swung.  You could drill a slightly larger clearance hole to get the adjustment you need.  The holes are 5/16 x 18 TPI and are .750 off of the centerline measured with a square held against the flat part of the crosslide facing you and the blade lined up with the 0 degree witness mark.  As far as distance away from the compound dovetail plug, look at the pictures.  The holes are exactly centered on the innermost wear mark from the compound.  Drill and tap the holes in the crosslide.  Put it back on  the lathe,  Get yourself some Heiman transfer screws, install the mill attachment with the tips of the transfer screws slightly above the top of the hole, square it up against the spindle with a DTY then give the mill base a whack with a brass hammer to transfer your punch marks.  Drill a clearance hole and you should have enough wiggleroom to tap the base back and forth 5 or so tho on the screws.  Do the same for other convenint angles such as 60 degree  45 degree or whatever you use most.  You can also have someone mill an arc slot like the SB attachment.

P.S.  If you do put the holes in make sure the screw you use to bolt the mill base down isn't too long or it will touch the top of the crosslide dovetail.


----------



## SE18 (Mar 2, 2013)

Halligan, apologies. I didn't at first see the pdf. Thanks for the explanation. Will see what I can do.


----------



## SE18 (Mar 3, 2013)

after looking at the diagram and the placement of the holes, I'll need to do the entire mill attachment over again, as one of the holes is right where the angle plate face is located. I also need to search for an F drill bit as that's what 5/16-18 takes. The diagram pdf shows the placement for a 9W. Mine is a 9A so am I assuming correctly that this would work for my South Bend 9A? I've never heard of a "W"


----------



## Halligan142 (Mar 4, 2013)

I belive 9W designates a 9" Workshop lathe which encompases the A,B,and C models.  You would technically only neet one hole drilled and tapped.  I believe the other is there to be able to swing the attachment in the other direction.  There was also an optional offset base that may have used it, not sure.  As long as one hole lines up it'll give you something to keep the attachment from twisting on its dovetail.  Then again if it works fine for you without the extra hold down then it's all good 

P.S.  HomeDepot sells taps with the tap drill included in the package.


----------



## SE18 (Mar 4, 2013)

ok, thanks again


----------



## SE18 (Mar 28, 2013)

Update: my F drill and all the other # and ltr drills arrived in the mail from Amazon so I drilled and successfully tapped 2 holes into the crossslide and also drilled thru the mill attachment. Everything is working fine now, with no more rotation with heavy cuts. However, I discovered that still, lighter cuts need to be taken because heavy cuts set up a harmonic vibration. Seems odd, but I've come to the conclusion that a lathe is not a standin for a mill. 

I would highly recommend the type of attachment I made, however. If you start to add other things like vertical screw, that would be good for function but it would likely add to something that could vibrate around.

My attachment's center of gravity is low. It is beefy and it is probably just the right thing I needed.

I likely will make one more attachment in the future which will be even more simple, that being a flat T-slotted plate. You can't get more simple than that and that would put center mass even lower.

Also, in future I'd like to do two things: make myself some sort of t-slot to replace the compound rest and secondly, to get a real mill, perhaps a Grizzly mini or a big Bridgport on sale.

Anyway, there are dozens of different mill designs out there to attach to lathes, but I'm happy to report that the one I made seems to be the only one of its type, offering flexibility of using the vise or of using the threaded holes in the back plate. The only improvement that I would have made would have been to replace the threaded holes in the back plate with T-slots. However, a substantial mill with t-slot bit would have been required for that.

Dave


----------



## SE18 (Mar 28, 2013)

Here's an angle plate almost exactly like the one I ordered with 3 vertical slots on the front which you can use to slide the face plate up and down and even tilt 360 degrees. The bottom slots look someone different but that shouldn't matter if you use a base plate like I did.

http://www.amazon.com/AP-202-4-1-We...F8&qid=1364475691&sr=8-9&keywords=angle+plate

the cost of making one of these angle plates in materials alone, not including the welding and time you'd spend make this a bargain IMO

Dave


----------



## cbtrek (Mar 31, 2013)

Very good job! I was thinking about doing something like this but this looks better!


----------



## SE18 (Mar 31, 2013)

I spent more time in the garage milling and mulling over some vibration. The vibration was, I determined, caused by loose gib screws in the crosslide, which I tightened.

However, you need enough looseness to move the crossslide back and forth. The solution to make this mill attachment even more rock steady would be a steady rest, as described years ago, which I might try my hand at:

http://books.google.com/books?id=ot...e&q=popular mechanics mill attachment&f=false

DaveV


----------



## bcall2043 (Apr 1, 2013)

Nice job! 

I tried milling in my lathe before I got a mill/drill. Your setup looks much better than what I cobbled up.

Benny
The Orphanage Never Closes


----------

