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Lynn Standish
08-31-2005, 05:03 PM
I’ve not had any real experience at milling. I have a Palmgren milling attachment for my 13 x 40 lathe, and I’ve used it a few times with mixed results. I’d like to use it to mill the corners off some rectangular 303 stainless pieces. My thought is to use an endmill in the chuck, with the parts held at 45* to the endmill. My question is whether I can safely mill the desired depth in a single pass. I want the face of the beveled corner to be .125” wide, so the depth of cut would be .0625” at the apex of the triangular cross section being milled, tapering to .000” at the other two corners of the triangular section. Is that doable, and what speed/feed should I use? Thanks for any hints.

John Stevenson
08-31-2005, 05:52 PM
Lynn,
The biggest problem I can see is holding the cutter.
Endmills in a chuck do have a tendancy to walk out.
Can you hold the cutter in a collet?, I don't know what equipment you have.

John S.

Lynn Standish
08-31-2005, 06:02 PM
John,

Thanks for the reply.

I've got the lathe with a 4-jaw, 3-jaw, and 6-jaw set-tru. I don't have a collet chuck. I have a drill press with a cross vise, but I'd think that would be worse than trying to use the 3-jaw on the lathe.

My problem is that I have several pieces I want to bevel the corners on, and I'd like to have things nice and uniform, rather than trying to file each one by hand.

I do have a couple of slotting saws and a mandrel, but it seems the problems with that might be the same as for an endmill.

WLW-19958
08-31-2005, 06:15 PM
Hi Lynn,

What is the inside taper of your spindle? If it is a "standard" taper (where you can get an end mill holder with the same taper), I would used an end mill holder. This would be cheaper than getting a collet set-up and would hold the end mill better than a collet IMHO.

Just my $.02
Good Luck!
-Blue Chips-
Webb

Al Messer
08-31-2005, 07:27 PM
Hey, Lynn! I used my lathe to turn a MT-3 milling cutter for my lathe, threaded the back end for some, I think, 1/2" threaded rod, and after the cutter holder was fitted in place, drilled and bored the holder to fit the 3/8" diameter of the shanks of the end mills I was planning on using. Do you have a copy of the little booklet "Milling In the Lathe" which is one of the Workshop Practice Series? This has a lot of useful information in it about milling in the lathe.

Al Messer
08-31-2005, 07:29 PM
Whoops! Forgot to add that the side of the holder is drilled and tapped for a 1/4" set screw to bear against the flat on the shank of the end mill and keep it from slipping and sliding around.

J Tiers
08-31-2005, 10:01 PM
Short answer is NO taking 0.0625 off the corner of SS in one pass would not likely be a good idea.

It's not the lathe, but the Palmgren. Way too bouncy.

I'd figure on about 0.010 per pass. Really.

Lynn Standish
09-01-2005, 09:33 AM
Thanks, everyone. I'll look for the book on milling in the lathe, and try to run down an endmill holder with a taper to match the spindle. I'm hoping to move next spring to a place where there is room for a mill, so that will solve the problem then.

sch
09-01-2005, 09:53 AM
MT3 collet holders that are threaded run about $20 each and would be very concentric inside the MT5-MT3 adapter. You should consider making one of the many simple 5c collet adapters for your lathe. Essentially all the work needed to make one can be done on the lathe itself. Another option would be one of the straight shank ER25 or ER32 adapters and using ER collets to hold the EM.
They are not through collets like 5c but grip over a much wider range. Straight shank adapters are in the $50-100 range.
Steve

rkepler
09-01-2005, 09:57 AM
The other thing to watch out for when milling in the lathe is that you don't climb mill. For some reason it's a lot easier to set up that way in the lathe than in a knee mill, but the additional slack in the ways on the lathe make it a real disaster.

Climb milling is when the tool is turning "over" the work such that the tool is pulling the work into the teeth. With a big mill and some drag on things it works pretty well, but on a loose mill or a lathe all that happens it the first couple of cuts pulls the work completely under the cutter and something gets broken.

But climb milling very fine cuts can be done and usually gives a very nice finish.

Evan
09-01-2005, 10:06 AM
Climb milling isn't what you have to look out for. I have done a LOT of milling on my SB9. You have to make sure that the cutting action is not tending to lift the carriage off the ways regardless of whether it is climb milling or not. Also, make sure the cutting action is pushing against the direction that you are moving the work, not pulling with it.

loggerhogger
09-01-2005, 10:33 AM
I do some milling on my 12" craftsman. I found that light cuts and lots of lube give the best results. also, try to "feel the feed". Don't try to make it bite off more than it can chew.

jburstein
09-01-2005, 11:16 AM
"Also, make sure the cutting action is pushing against the direction that you are moving the work, not pulling with it."

So, in other words...look out for climb milling?

http://bbs.homeshopmachinist.net//biggrin.gif

-Justin

Evan
09-01-2005, 11:28 AM
Yes, but. Making sure you don't lift the carriage comes first. You can't always have both milling on the lathe. If you have to climb mill it helps to tighten up the gib screws to put some extra friction in the system.

JCHannum
09-01-2005, 11:43 AM
Climb milling will tend to lift the table or carriage, and pull the work into the cutter. Conventional milling pushes the work into the table or carriage and will tend to overcome backlash in the system.

There is a good explanation here;
http://its.foxvalleytech.com/MachShop3/basicmill/backlashIS.htm

Lynn Standish
09-01-2005, 02:24 PM
Again, thanks for all the info, but I think I may need to find another way. I have 6 pieces, each with 8 edges to be beveled = 48 edges. If I use a depth of cut of .010 to get to a depth of .0625, that's 6 cuts per edge. 6 cuts times 48 edges = 288 passes. I'm thinking there's got to be a better way.

Evan
09-01-2005, 02:25 PM
Belt sander?

Lynn Standish
09-01-2005, 03:40 PM
Evan,

Yes, perhaps. I've kind of been looking at the small combo disk and belt sanders with tilting tables and a miter gauge. I really don't have room for that, either, but maybe I could work something out to set it up when needed.

I gotta move. The house is paid for, so it's just a matter of trading for less house and more shop. The nest is empty anyway.