Face milling with a small mill.

Ken from ontario said:
Bobshobby, thanks for joining in and for your comment, throughout this long thread we have covered a few of the misconceptions you are talking about already,i.e. 3 point cutter vs 2 point or one, 3 point EMs being the least suitable for a mini mill due to their lack of power and rigidity ,my original post was what I had gathered by reading other threads relating to indexable end mills and their appropriate sizes for smaller /less powerful milling machines but the more seasoned members did put me on the right track but thank you again to reiterate the points for clarity.we are here to learn and I for one appreciate all the help I could get .
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Ken, back to your original question, you mentioned the max. dia. of a milling cutter on your small mill. If you use a single point cutter, aka a fly cutter, the only limit to dia is how big a cutter can you swing without hitting anything. The other factors you will need to consider if you have a variable speed motor rather than a gearbox do you lose much torque at low speeds, if so that could also limit the size. Also make an effort to balance the cutter so that the spinning out of balance does not cause wobble problems. make a large dia cutter head so as to act as a flywheel this will help with balance but also help with torque when cutting at low speeds. With a large dia cutter head you can drill a radial hole diametrically opposite to the cutter, and fit a bar without cutter to be used as a balance weight.
 
bobshobby said:
make an effort to balance the cutter so that the spinning out of balance does not cause wobble problems. make a large dia cutter head so as to act as a flywheel this will help with balance but also help with torque when cutting at low speeds. With a large dia cutter head you can drill a radial hole diametrically opposite to the cutter, and fit a bar without cutter to be used as a balance weight.
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That's one solution I never thought about , thank you for that.
I got my 1", 2 flute end mill the other day and used it on low and high RPMs got acceptable performance, this mini mill doesn't loose much torque in lower RPMs which is a good thing but overall, I didn't like the finish I got with the 1" indexable end mill, the next size down I used was the 3/4" roughing end mill that worked absolutely great .
 
When I think, "small mill", I think a machine with a maximum .500" dia collet capacity. I am familiar with the challenges regarding this limitation.

My main mill is a Clausing 8532. It makes me a very good living. I use a cordless, variable speed, 1/2" drill motor with 5/8" socket drive for power feed on X and Y axis. It has DRO on the Y. The X axis is still true on 6" passes in my use range. I can fish for .0001". I have used this machine for two decades in this application.

For face milling plastic, aluminum, brass and bronze, I recommend using a 2" dia, HSS, shell mill on a 1/2 dia shank. For smaller parts, try a reduced shank (1/2"), HSS, six or eight flute mill, 3/4, 7/8 or 1" dia. I get these mills from McMaster Carr, MSC, Enco and E-Bay. Look for the best prices and sales. I am interested in index-able mills, but they are largely not designed for .500" dia collets. I have no use for the ones that are. They are too small.

My experience has taught me to stay away from any HSS Chinese mills of this type, very disappointing finish grinding is the reason. US, Polish and Spanish products are of good quality. If I see Niagara (US) products of the above range on E-Bay, I hoard them.

I recommend using metal specific cutting fluid for the best results on aluminum brass and bronze. It makes a world of difference compared to all other cutting fluids. Tap Magic made my life a lot simpler.

I use continuous high pressure air for cutting plastics, no fluids. I face mill 1.75" cross sections with a 2" dia shell mill all the time. I machine PEEK, which is very tough and does wear out HSS with poor cooling. Match feed speed to cooling capacity at all times. Slow feed rates down for partially worn mills. I always go as fast as I can. Time is more valuable than cutters.

For facing aluminum, brass and bronze, I use Tap Magic applied with a trimmed flux brush, a very tidy way to lube a mill. Pre-load the mill and part surface, then let another loaded brush drag across the mill while the pass is made. Mind you, my work is on the small scale.
 
Thank you Richard for your post and sharing your experience.
You use "2" dia, HSS, shell mill on a 1/2 dia shank" with your small milling machine ? I thought 1" Dia. was too big for my mill, I never tried any diameter bigger than that. your mill must be more powerful/ridgid than what I have.

Great point on tap magic, I use it regularly on Aluminum but I also use WD-40 as well ,both seem to work fine.
 
mirain33 said:
I've been searching for a small face mill for my Clausing 8530. The largest collet I can use in the spindle is 1/2". Given that limitation can anyone suggest a source for a 1/2", straight shank, indexable face mill?
The smallest I've found is 3/4".
Thanks
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I highly advise to NOT use collets to hold endmills. Using good collets on my 8520 you really gotta crank down on the endmill to prevent slipping. Since switching to endmill holders I've no longer had slipping. I found a Bison MT2 5/8" endmill holder, though that's really pushing the limits of this machine.
 
Ken: There are many people writing their experience with Mills similar to your using the new and very inexpensive
1 Set 90 Degree R8 FMB22 Straight Shank Arbor Face End Mill Cutter 4pcs APMT1604 Carbide Inserts Turning Tool delivered in Canada for less the $50CDN
When I bought my Mini Mill LMS 3960 there was no tooling capable of making more than a 0.75 inch cut and even that at only a few thou DOC. Now things have changed with the more precise and inexpensive Chinese tooling most of us can now afford to experiment.
However the Good Old Fashioned Fly-Cutter can be made in your own shop and using HSS or Crobalt Both can be sharpened on the bench grinder with ease.
My latest experiments are from and article for a very simple Single Facet Face Mill see the article https://www.hobby-machinist.com/threads/small-face-mill-using-tangential-cutter.82442/
Good Luck and Stay Safe I have a good friend who live in Peterborough. My sister use to live near there as well.
 
Ken I found the article I was looking for on youTube with the small mini mill and the 50mm end/face mill
I have looked at several similar articles and the tool holder works the quality of the carbide inserts seems to be the deciding factor as to the finish. More than on article checked the Run out on the tool holder and they were found to be of very good quality.
The biggest differences were the varying grade of the carbide inserts used after a lot of searching I found several different grades and recommendations for cutting different material stock. One type of insert is not suitable for all materials. So while the tooling can be delivered to Canada very inexpensively the inserts will take more research depending on your milling material requirements.
The nice thing I have found is I can use PayPal which provides me a more secure financial transaction.
Best of luck on your project.
 
Thanks for resurrecting this 3 year old thread, I have since learned a few things about my mini mill/lathe:
For facing, I have been using a shop made fly-cutter and totally moved away from those indexable face/shell mills, it is my opinion that the larger 1.5" to 2" face mills seem to do extremely well with larger/more rigid milling machines, if I owned a bigger more ridgid milling machine I would consider a 2" shell mill.
For material removal/profiling, I use 2 or 3 flute good quality end mills no bigger than 1/2" Dia.
My shop time needs to be calming / soothing time and I've learned to achieve that by working within the limits of my machines.:tranquility:
 
Ken:
I totally agree with you on the shop needing to be a place of calm and restful emotionally experience. I do not work well under pressure. This hobby is to be enjoyed and should provide a source of increasing knowledge which can be reflected in the things we work on or attempt to create. My latest thoughts are the creation of a larger fly-wheel based fly-cutter. I am working on a project the Acute Tool Sharpening System Kit from Eccentric Engineering. I am using it as both a learning process and a creation project.
There is no time limit and learning how to better use what I have while building the project as you say brings a very calming atmosphere to the shop. There are several minor milling processes required which I have been thinking could be done with a fly-cutter. Not the first tool that comes to mind, as the instructions call for an end mill. Now since it is not making a grove in metal only making a step into the side of the work piece. my mind keeps asking why not use a simple fly cutter. Slow yes, but I just said there is no time limit requirement. The Fly-Cutter similar to the simple concept found here https://www.hobby-machinist.com/threads/small-face-mill-using-tangential-cutter.82442/ It is not about the finish rather it is about the creation of a simple tool holder containing a simple HSS or Crobalt tool bit used to perform the milling operation.
This I Think is what you are striving for when you say the Shop should be a place of Calm. A place where simplicity rules the atmosphere.
Thanks for Listening
Dave C
 
I agree that machining can be a calm and relaxing experience! I love fly cutting, and I have very heavy machines... It is a process where you can control the surface finish, the accuracy, and on a well-trammed machine, leaves perfectly flat surfaces.
 
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