Milling tools for a Unimat SL 1000

[mogogear]

I am going to need some basic - starter milling bits for my Unimat... if this info is in the forum some where - just point me to it please!!

I assume I will need about 3-5 ?? If all of you are laughing!! Thats cool- I have no Idea if I need 30 or 3.. :-[

Fire when ready!- and thanks in advance!

 

[Circlip]

Basically Mogogear you've asked the question "How long is a piece of string" Buy the largest cutter within your machines capability to achieve the milling operation you want to carry out. OK, you can't cut a 1/16th slot with a 1/4" cutter, but it takes a long time to cut a 3/8th slot with a 1/16th cutter. Buy what you need WHEN you need them, but don't buy cheap, Quality deals from Thiefbay do come up from time to time and look at the tool gloats that some of your colleagues over there get from yard sales.
Regards Ian.

 

[Kludge]

I've got to agree with Ian here on getting what you need when you need it.

To refine it a bit, the DB/SL Unimats don't have a whole bunch of power so 1/4" is a hard upper limit with 3/16" maybe a better choice. If you want to build a basic starter set, maybe 1/16", 1/8" and 3/16" would be a good set with room to grow as you need it to. If I were starting over now, that's the group I'd use with my SL-1000 instead of the hodgepodge of oddballs I have now.

Of course, their being oddballs means they fit me well. ;D

Best regards,

Kludge

 

[Circlip]

Morning big K, save the next dance for me :big: Don't you find it sad that some newbies think that we're going to flood their questions with scorn and derision?
Anyone trys to down you Mogogear an' there's two of us who'll jump in.
Regards Ian.

 

[Bogstandard]

Mo,

See anyone laughing?

We all had to start somewhere. Asking simple questions will not only get you good answers, but save you loads of cash and time as well.

John

 

[Tin Falcon]

Mo:
I see good advise so far.
Since your unimat is limited to small tooling you may want to consider duplicates or get one "set" of two flutes and another 4 flute.
Also one of my favorite milling tools is the fly cutter, very versatile.
Tin

 

[chuck foster]

hi mo

i was just going over my ebay account and here is a guy that i have bought from in the past and i have been very pleased with his product. all endmills are solid carbide and his shipping is fast.

http://stores.ebay.com/CARBIDE-PLUS_W0QQcolZ2QQdirZ1QQfsubZ0QQftidZ2QQtZkm

i have a unimat and they are a great little machine but you do have to remember that they are small and don't try to work them too hard, otherwise they are ok.
as far as asking questions............the only dumb question is the question that didn't get asked. as others have said, we were all newbies when we started. i have been building models and machining stuff for almost 30 years, and when i see some of the stuff these guys are producing on this website it makes me think i'm still a newbie.
hope this helps and when you get started making something..........anything you will have to post pictures ;D

good luck with you new found hobby

chuck

 

[mogogear]

Ahh- I really wasn't scared..I actually had a hard time figuring out what to call them ,,bits, cutters etc.. :-[

K, the "how long is a piece of string " was a fair analogy...I will do a little better on specifics ......BTW the 3 smaller sizes given as a reference was spot on advice, so I don't try to overpower my little machine..that was a very useful pointer- thanks

What is a "fly bit" purpose? Does it "face " a piece of stock? Or does it cut a circle?

Thanks again folks--

 

[Kludge]

Morning big K, save the next dance for me :big:

Imagine, if you will, an elephant running downhill. Backwards. On three legs. Drunk out of its gourd. This is a fair image of some of my better attempts at dancing. ;D

Don't you find it sad that some newbies think that we're going to flood their questions with scorn and derision?

There are too many places where that is precisely the response they'd get. Here, it's family and no one picks on family. Successfully.

Mo, none of us was born with a zillion years of experience with every tool ever made and an extraordinary number of ones not yet invented. We all took that first step and are fortunate enough to remember that stage - and everything that went with it. (I have a private opinion regarding the psyche and/or ego of the folks who would be derisive but this ain't the place. )

Anyway, stated another way, you and I have stumbled into a group of people just as crazy as we are. Ain't it cool?

BEst regards,

Kludge

 

[Bogstandard]

Mo,


As they say about pictures, this shows it all.

A flycutter in action on a small mill.

[ame]http://uk.youtube.com/watch?v=7_5lzJm1NzM[/ame]

It is one of the easiest methods to produce a good surface finish over a relatively large area.

John

 

[Kludge]

Ahh- I really wasn't scared..I actually had a hard time figuring out what to call them ,,bits, cutters etc.. :-[

"Thingies" works in a pinch. ;D

K, the "how long is a piece of string " was a fair analogy...I will do a little better on specifics.

That's why I gave some specific sizes, to offer a starting point and narrow down how long that string actually is.

BTW the 3 smaller sizes given as a reference was spot on advice, so I don't try to overpower my little machine..that was a very useful pointer- thanks

If you happen to stumble across one of the [somewhat rare] 8mm watchmaker's headstocks for the Unimat within a price range you can afford (even if it requires a second mortgage), grab it. Watchmaker's collets are extremely precise and are available in metric from .1mm to 8mm, and in Imperial from 1/16" (1/32"?) to something around 3/16". (I don't have any Imperial and I'm not a whole lot of interested in it so I'm not sure.) There's a third group that I think is Stubbs wire gauge as well. Some wire gauge anyway. (This doesn't include a variety of chucks and other cool things that can be used with an 8mm lathe.) The headstocks themselves are a bit more refined than the normal ones so they offer slightly better precision and sideload handling characteristics. And this headstock is an almost ideal match to the power available with the Unimat's motor.

With that, a couple of folks on eBay make accessories specifically for the Unimat. One such shop is Precision Mars at http://stores.ebay.com/precision-mars. Their offerings vary somewhat dependent on what they've had an opportunity to make (It's a very small operation!) Also Tom Smith (http://search.ebay.com/_W0QQsassZclassicsarts) has a variety of adapters worth looking at though his endmill adapters are a bit on the large side (1/4" & 3/8"). And finally Bob101cnc (http://search.ebay.com/_W0QQsassZbob101cnc) has some cool stuff as well including an oversized milling table. I've bought from all three and have not been disappointed.

What is a "fly bit" purpose? Does it "face " a piece of stock? Or does it cut a circle?

Why, to cut flies, of course! Far better than a swatter or other means of getting rid of those pesky critters. ;D

Anyway, Bogs' reply is, as usual, wonderfully instructive.

Best regards,

Kludge

 

[Bogstandard]

I forgot to mention about something on that vid about the flycutter.

If you notice, as the flycutter had finished the first cut, there was a secondary cut following it up. This shows that the head on the mill is not truly square to the table. This can be used to your advantage as it gives a great surface finish. It will only do it in one direction, either left to right, or right to left. See if you have it and use it to give yourself better results.

John

 

[Stan]

You have lots of good answers. I would add at least one ball end end mill because you will want to do some concave cuts to bling up some of the parts. Be sure to get center cutting end mills, especially in the two flute ones, and nice to have in four flute. Without center cutting, you can not plunge cut and you have to drill a hole to start.

 

[mogogear]

What a great rally of advice

So an end mill can have 2 or 4 flutes- or grooves that are twisted around the shank.. that give effect how much material is being cut at once, and related to the type of material being milled and would seem to have a direct effect on speed and amount removed in one pass?

The end of the mill can cut ( able to PLUNGE) or be ball ended so it ran ride along on a plane and cut perpendicular to an established plane. Like a ball ended router bit..

An end mill range suggested by Kludge 1/16,1/8 up to 3/16 ( cutting end) But Mr. Kludge is there a spec shank diameter? 3/8 for example, and if so all end mills should be that size..I am used to drill chuck steps - so 1/4, 3/8 1/2 etc - Just double shecking this small point

I notice that I may need an end mill holder to lock the end mills into ( I saw a steel custom version of one of these on one of the sites that Kludge shared above..$18 and some change for a steel... stated up to 3/8" or 1/4" - would one be the best all round choice?..the 1/4" since my lathe can only handle end mills of 3/16" or do I need the heft of the 3/8' more ..

Try to have some end cutting, at least one ball end end mill.

And a fly cutter- thanks Bog for that video--- that was spot on. Now since my little lathe is small..small - is there a fly cutter diameter that I should not exceed?

Now that you all have proved yourselves so helpful.. I shall try to read , some , study up some and then ask questions.. I am pretty handy, have a good mechanical sense 20 years ago I was a auto mechanic for Cadillac,,, but the only lathes I saw were for brake rotors...Not very enlightening..

I do have a couple of old lathe books " Machine Shop methods by Milne and an South Bend lathe book reprinted form the 1930's.. + this forum - I am not too scared

Gentlemen - Thanks.... and if it applies, have a great Labor Day Holiday

 

[Cedge]

Mo
Everyone has given you good advice and your response indicates you have a grip on what you've been told. I'll add one more item to your list. A tooling catalog. Travers Tools and several other suppliers offer them for free. It's not that you'll buy that many tools from them, but that you can quickly look up information and photos of tools you see mentioned by others along with many many that aren't. It's really an educational book that you can keep right there in the bathroom, as long as you don't get it mixed up with the Sears catalog serving other purposes....(grin)

Steve

 

[Bogstandard]

Mo,

This is very basic info on milling cutters.

http://en.wikipedia.org/wiki/Milling_cutter#End_mill

This one has a few bits about tool holding and a few vids to watch on a rainy afternoon.

http://web.mit.edu/2.670/www/Tutorials/Machining/mill/Description.html#3

Searching for information on the web usually throws up a lot of garbage, but in some cases, real gems. Once you find one, add it to your favourites.

You can buy a trio set of basic flycutters for a few bucks.

http://www.grizzly.com/products/Fly-Cutter-Set-1-2-Shank/G5716

You will need to learn a little about tool grinding, but that will stand you in good stead anyway.

Will your little machine cope with a flycutter? It should do. In fact you little machine should be able to cope with almost any sized cutter. Just don't take as much off in each pass. The machine will usually let you know if you are overloading it.

If you don't normally take much notice of safety precautions, the fly cutter will eat you up and spit you out in bits. It can be your best friend or your worst enemy.

Red hot bits come off these cutters at a speed and range like no other, so protective glasses HAVE to be worn. No exposed soft skin (v-necks, open shirts, shorts etc) otherwise you will be jumping around trying to get hot shards of metal off burning skin, and because of the openess and large radii of cut, definitely no loose clothing, long hair, rags, poking sticks or digits anywhere near the running cutter. All this goes without saying about machining, but fly cutting especially if you are normally a little lax in your own safety. Now you are scared to death of using the flycutter, get in there and try it out. Treat them with repect and a great deal of caution, and you will soon learn it will be one of your most used tools.



Bogs

 

[Kludge]

What a great rally of advice

Actually we just like to show off that we still remember something. :big:

But Mr. Kludge is there a spec shank diameter?

Except for the carbide bits someone else mentioned all of which have 1/8" shafts, my experience is that the mills' shaft diameters are the same as the mills themselves (except ball end. They're a different kettle of fried rice.) Lacking collets (which are available for the Unimat, just not cheaply), a drill chuck works. If you wind up using Tom's adapters, you'll need an insert to adapt to the actual mill shaft diameter. His own machine's been tricked out a bit so has a wee bit more power and can handle the larger tooling.

By using the 3/8" adapter, you can turn then drill & ream adapters for smaller sizes, creating them as needed. I know Tom's adapters are spot on for concentricity so that isn't an issue. By the way, the same trick works for turning smaller round stock on the lathe. It's not as good as collets but it's a decent second choice.

Again, Bogs has offered some almighty wonderful information in the form of the URLs he mentioned.

Quoting him:

If you don't normally take much notice of safety precautions, the fly cutter will eat you up and spit you out in bits. It can be your best friend or your worst enemy.

Further, it can do both at the same time. The best thing to do is practice Safety First without exception.

Just double shecking this small point

Shouldn't that be double Sheping? ;D

but the only lathes I saw were for brake rotors...Not very enlightening..

What? No drum lathes? No shaping shoes to match the newly turned drum? I bet you never had the pleasure of riveting new shoes to backing plates either. *sigh* ... I'm showing my age, aren't I.

Gentlemen - Thanks.... and if it applies, have a great Labor Day Holiday

Living 50 yards from the ocean with a beach park between me and it, I shall have plenty of "entertainment" without having to leave my apartment. Some of it gets pretty ... ummm ... interesting. Yeah, that's the word. Interesting.

BEst regards,

Kludge

 

[Circlip]

Sorry to clash swords on this one Kludge, but I would never advise a newbie to use a chuck for holding milling cutters. It may be expensive to buy an adaptor, you could even make one, but we're on a don't bend a novice work safely drive. ;D

Regards Ian.

 

[Bogstandard]

I forgot to add to your question about shank size.

Normally for 1/4" (or 6mm for metric) and below, shank size is usually a standard 1/4" or 6mm if using HSS type cutters.

If you buy tungsten this can vary from supplier to supplier. I have seen the shank size the same size as the cutter IE, 3/16" cutter, 3/16" shank. Until you reach 1/8" and below, then the shank size usually standardises on either 1/8" for imperial and 3mm for metric cutters.

I have found that the cheapest sort of prices for small cutters are what are called 'disposable' cutters. They are usually a 3 flute, centre cutting design and can be used as slot or end mills. I think they are made for CNC routing machines (for making circuit boards and engraving etc), but are perfectly serviceable for the sorts of materials we normally use. The cheapest I have bought them for was £4 ($8) for 8.

For those that live in the UK, Arc Euro has a special on at the moment, 4 flute centre cutting, (in 0.5mm steps) £2 each for smaller ones, £2.50p each for the rest up to 12mm (see bottom pic for type), they do full sets at a discount, and I can reliably inform you, they cut great.
No I am not a salesman for them, but a very satisfied customer with the quality of the parts, and speed of turnaround of orders.


John

 

[Mcgyver]

i agree holding endmills in a chuck is bad practice but you might not have much of a choice with unimat, 3 jaw chuck that is. collets seem like they were a rare accessory. the spindle nose is not a taper so a diy version is more work, and not a newbie project, and not something you could likely to without benefit of larger machines. I suppose you could set it up in the four jaw and indicate but who wants to do that every time?

the end mills held in a chuck will act a bit like a fly cutter, cutting on one tooth, as the chuck doesn't hold as concentric as a collet......although, the oem unimat chucks are amazing accurate in that respect. you can't see any runout whereas usually a couple if thou is very visible. The other problem is grip, the small surface area of jaw and the low coefficient of friction present when holding a hardened end mill means they can slip - this can damage the jaws.

I good diy project would be some simple end mill holds. hold a cylinder of steel in the three jaw and mark on it the location of jaw 1. bore to the OD of the end mill, work carefully to get it dead on. drill and tap an intersecting hole for a set screw to hold the end mill. repeatability should be good if you put the mark to the jaw it started with. cutting steel on these little lathes , but working slowly and with light cuts can be done

These are fun machines, turn and drill well but the weak link is the mill. forget fly cutting, unless on plastic or something very easy to cut. use the lathe as much as you can - ie rectangular prisms and flat surfaces are made via facing cuts in the four jaw - for bigger items, its the old fashioned way - learn to file square on the bench.