Mini Mill accessories...

[Osprey Guy]

Now that I've got my HF mini-mill, I thought I might put it to better use than just looking good on the new bench (I added yet another work bench...that makes five!) ....

So I guess now I'll need to start buying all the required goodies to make it actually operational.

As is my want, I've already spent hours researching the various "accessories"...I should say I'm most impressed with littlemachineshop.com. They've done a very good job doing a lot of the legwork for us, and they're prices offer some of the best bang for the buck!

I've already pretty much nailed down my thoughts about a good vice,...but before I buy I need to check out a "high-end" vice being offered to me for free from a friend.

Last night I was telling this friend about an end mill set they have for sale. When I told him I was planning on buying the 4-flute set rather than the 2-flute, he stopped me right there..."4-flute is no good!...For what we do you need 6-flute" (We're both foucused more on fancy folders). He qualified that this advice had been passed along to him by a master machinist (whom we both know). In the littlemachineshop minimill tutorial section, they explain about 2-flute being good for rapid removal, and 4-flute is for finer work. They suggest that if you're just starting to buy equipment to begin with the 4-flute set. When I checked ENCO and MSC for 6-flute prices I came away with serious sticker shock!!! ....Most 6-flutes start at around $45 bucks apiece and quickly get up into the $80's and $90's!!!

Any thoughts?


Dennis Greenbaum

Yeah Baby!

[Rob Frink]

Hello Dennis! Congrats on the new aquisition.

You'll need a universal dial indicator. You will use this to align your vise, square the head to the table and who knows what else for. A magnetic base is very handy.

In regards to 2,3,4,5,6 flute. This could become a very long and confusing discussion. For me, 2 flute end mills have less chatter and are great for making deep slots and pockets where the full width of the tool is cutting. In the same application, a 4 flute may chatter....if you are cutting deep. But on the other hand, if you are cutting along the edge with only 20% of the width of cut....you can feed the 4 flute end mill 2x faster than the 2 flute...and even faster with 5 and 6 flutes.

Each set-up and application may require something different...which you'll learn with time and experience. There are no "hard" rules in this machining game and as soon as someone says "it won't work" some else will share thier success stories. If it were me....and I only had one style to choose from which would do 100% of all my work....I would use a 2 flute. The reason is I feel that a 2 flute will do everything a 4 flute will do and more..... but at a slower rate.

The other decisions are materials, and coatings. .... High speed, Tungsten, carbide, TiN coated, ...etc. There choices are endless. They all have trade-offs. You pay for what you get in terms of performance and life. I would stay away from the box sets and buy a few individual end mills to play with.


Have fun with it! ...and wear safety glasses when running it.

Take care,
Rob

[SKIVIE]

Dennis, Your gonna love your new toy. My father in law machined me a nifty little vice that works wonders. Im really unfamiliar with the vises that are available so I cant help you much, but I do agree with Rob on the 2 flute. I have some 4's but have not used them since getting the 2 flute. Also youll find youll get the most life out of your bits if you are running at the right speeds for the right material your milling. If you are in need of that let me know what types of material youll be milling and I can work it up for you.

Your going to come up with all kinds of things you can do know that you have it.

Shane

[Messinger]

Hi Dennis,
I don't have anything to say about the end-mills - there are REAL machinists here like Rob who'll give you the straight dope on that stuff - but I do have a few suggestions for you as I just got my mini-mill up and running not too long ago. Do like Rob said and get a dial guage and magnetic mount. It comes in reall handy. There are a few things you are going to need to do to get your mill running right. First, you'll want to do something about the chuck. The as-delivered mini-mill chuck is terribly inaccurate. Get a good Rohm or Jacobs precission keyless chuck. As delivered my mill had 7 thousandths of an inch runnout. I installed a Rohm keyless chuck and now the runnout is about 1.5 thousandths. Second, you WILL need to true up the table to get it square with the head. Mine was off a bunch. I used shims undder the upright support to true it up using the dial guage on a boom in the chuck as a reference, moving it around the table to check for square. Picture a rod in the chuck, with a boom attached to it extending out horizontally with the dial guage mounted at the end of the boom. This is the same principle as the 'Z' shaped piece of wire trick you use with the drill-press, but it's more precise to use a dial guage. Machinists here may offer a better method but it worked well for me. Just FYI the chuck was only about $25 and the dialg guage and stand were $15 together. It was money well spent to get the mini-mill tuned up and working great.

-Ben

ps - nobody has said anything yet about clamps, so I'll mention that - Get a clamp set! For making folders it will be even more important than a vice. I'd add that Don Robinson's "My Way" book is another worthy mini-mill accessory (or vice versa)

[Jeff Higgins]

Hi Dennis,

I'm a master machinist (if there is such a thing). Rob is correct in what he is saying, but I simplify things a little more in that I use 2 flute for non-ferrous materials and 4-flute for ferrous -OR- anything that is tougher, ie Ti. Rob alluded to feeds and speeds and really it all boils down to the correct feed rate and the correct rotational speed of the size bit you are using. There are formulas for these that calculate end mill size by speed and gives you the feed in inches per second and so on, but I have long-forgotten them. Machinery's handbook is a good place to start. It all comes down to the cold hard truth that 2 flutes will clear away gummy/sticky materials faster than four flutes and the four flutes will cut better on steel, but either will do for our purposes. Anything with more flutes than 4 are typically regarded as specialty mills and we really don't need them for knifemaking.

[jwfilion]

At last, a question I can answer. I too am a master machinist , been certifiable since '76. Basically, what Jeff said. The 2 flute endmill, aka slot mills or slot drills, is a good all purpose cutter for the average small mill job. The 2 fluters were used almost exclusively for cutting blind keyways. They seem to be more accurate at these jobs than the 4 flute which I've been told requires perfect feed/speed calculationn per material composition to get it to cut a slot without vibration which causes inaccurate cuts. One trick is to use a cutter of smaller diameter and sneak up on it. I use the 4 flute for edge cuts, surfacing, etc., they produce a smoother finish. They also make centre cutting 3 and 4 flute mills for blind slots as well.As for the composition of the mill, each has a specific purpose. it seems the more specific, the higher the cost. You get what you pay for!

[jwfilion]

An afterthought: http://www.practicalmachinist.com
Another great forum.

[Tbonz]

I recently added the HF Mini Mill to my growing assortment of knife making tools. I have one thing to say, I love this tool. I've had it up and running for a week and I have been using it to great advantage for jobs that I had'nt even considered when I purchased it. I've milled the edges of scales and bolsters for a tight fit. Milled pairs of bolsters for a perfect match. Cut slots in guards and milled a one piece bolster/liner combination for a small folder. Awesome tool.
I purchased accesories from several sources, chief among them was The Little Machine Shop. From the LMS I purchased the 3" precision swivel vise for $89.95, a great tool. The 3" long thin parallel set was another worthwhile purchase from LMS. I purchased end mill holders over the collets. You will quickly find that the initial accessories could cost as much as the Mini Mill itself.
Have fun Dennis

[Osprey Guy]

Everyone warned me that the accessories would cost at least as much as the mill...so I'm prepared for that. After thoroughly checking out all the usual suppliers for small, "precision" mill vises, I already came to the conclusion that the 3" precison swivel vise from littlemachineshop.com was going to be my best bet. I do need to first check out that vise offered to me by my friend (He says it's a $600 vise and I'm sure it is...But I have a feeling it's going to be a little too large for any practical use with the mini-mill).

From what I've read, I have a feeling that the end mill holders are the way to go over collets (I read that most opinions as to which way is better, are pretty much split right down the middle).

I already have a set of 1/8" parallels, which I bought awhile back for use with my drill press and the cross-slide vise I bought for that.

I will be placing an order for a hold-down clamp set, and an indicator with a magnetic base. Mini-mill.com highly recommends a surface gage...I'm not real clear as to the difference in use between that and a dial indicator. I do own a surface plate...I bought it about a year ago. It sits just to the right of my main workbench, and it's in constant use.

As far as the chuck goes, that was my first and easiest decision. Everyone strongly recommends that I ditch the piece of crap chuck that comes with the mill (One place suggested that perhaps this was China's way of unloading their surplus supply of worthless chucks) I'm absolutely nuts about the keyless Rohm "Supra" chuck I bought from Enco for my Delta variable speed drill press...what an amazing difference from the old chuck! So I won't hesitate to buy another one...this time for the mill.

Regarding the end mills,... I guess I'll have to experiment for myself. In addition to the free vise, my friend tells me he's gonna give me a few of his 6-flute mills (I think he lucked into a supply of them awhile back...and he's kind enough to share).

Littlemachineshop.com has a video for sale, which deals with mini-mills...in particular various methods for securing/holding down work. I'm told that this is one of the most important things to learn about using a mill. I expect that to arrive in the next day or so...I'll let you all know what I think of it.

With luck, I should be up and running this time next week...Good timing...as I've already begun work on my next folder...and for a change, the design is fairly involved. Me thinks a mill might just come in handy.


Dennis Greenbaum

Yeah Baby!


BTW- I think I was one of the very first to purchase a copy od Don Robinson's "My Way"...Although obviously well done, at that time I received it, it might as well have been written in Greek! Not only did I not have a clue...but I lacked nearly every piece of equipment referenced in the booklet. Now it's time for what I suspect will be, a far more meaningful re-visit with "My Way"!