Learning to run the mill, machinist help please

timc

Got everything pretty much ready to start with the new to me mill. I have zero machinists experience but I do have learning skills and a lack of fear in screwing up one of my toys.
today I completed building the mist cooling system, that thing works pretty good. I used a magnet to attach it to the machine so I can move it around as needed.

I have pretty much all the endmills  I need to start, I may need some cutters and some measuring tools but not sure what to get. I think my biggest issue is squaring up the machine. I’m getting better but still have issues getting it righ and it is noticeable on long cuts.
I know we have some machinist folks here, I would appreciate any advice to work myself out of rank amateur status!

Linefinder

My first bit of advice is get rid of the mister. They create a heckuva mess and create a slip hazard you wouldn't believe. (and slipping around a running mill is something you NEVER want to do).Just fill a spray bottle with coolant and apply to the tool and piece as necessary.

 As to squaring the mill, what you are actually doing is squaring the vise to the quill along the X & Y axis. Once you've accomplished that, you square the head (quill) to the vise.

To obtain a modicum of accuracy you're going to want a test indicator.

Mike

Linefinder

https://www.youtube.com/watch?v=DdgSxoTmtx0

Good video on the subject.

Linefinder

As to cutters........

High speed steel works well on plastics and softer stuff. 2-flute is generally adequate.

For steel, carbide is the only way to go. 4 flute, all the time.

Personally (on my company's dime) I like to keep two cutters of each size on hand. One for "roughing" cuts and one for "finishing cuts. I like my roughing cutters to have a .015-.030" corner radius, (greatly increases tool life), and my finishing cutters to be dead flat (nice clean corners). If the degree of accuracy you need will allow a bit of radius in the corners, you'll find out the tools with corner radius far outlast flat endmills.

Fly cutters.....don't waste your time. A shell mill with multiple replaceable carbide inserts will save you a lot of grief, time, and eventually, money.

I'll keep adding as I think of it.

Mike

timc

Linefinder said:

My first bit of advice is get rid of the mister. They create a heckuva mess and create a slip hazard you wouldn't believe. (and slipping around a running mill is something you NEVER want to do).Just fill a spray bottle with coolant and apply to the tool and piece as necessary.

 As to squaring the mill, what you are actually doing is squaring the vise to the quill along the X & Y axis. Once you've accomplished that, you square the head (quill) to the vise.

To obtain a modicum of accuracy you're going to want a test indicator.

Mike

The video was definitely informative. I understand met of what I need to do. Too bad about the mister I thought it worked really well, feed is adjustable, the recommended just a very fine mist so there is not a lot of lube going everywhere. From what I read it was recommended just enough to wet a paper towel, but I am not the expert so you are probably correct.

timc

Linefinder said:

As to cutters........

High speed steel works well on plastics and softer stuff. 2-flute is generally adequate.

For steel, carbide is the only way to go. 4 flute, all the time.

Personally (on my company's dime) I like to keep two cutters of each size on hand. One for "roughing" cuts and one for "finishing cuts. I like my roughing cutters to have a .015-.030" corner radius, (greatly increases tool life), and my finishing cutters to be dead flat (nice clean corners). If the degree of accuracy you need will allow a bit of radius in the corners, you'll find out the tools with corner radius far outlast flat endmills.

Fly cutters.....don't waste your time. A shell mill with multiple replaceable carbide inserts will save you a lot of grief, time, and eventually, money.

I'll keep adding as I think of it.

Mike

Nice, all I really have is end mills with a fee cutters that came with the mill, I’m not really sure what to get. CPJ is going to send me some links. I’ll spend what I need to get the right stuff. The wife is pretty cool about it and I think there’s a law they can kill you but not eat you so I’m good. Please keep sending anything you think I need to know or get.

Linefinder

A misters best application is within an enclosed CNC when the computer controls won't "quite" allow you to direct the flow exactly where you need it. We have four in my shop. Three are still in the box, and the other has been collecting dust for 9 years. OTOH, everybody has a Windex bottle full of coolant and a small container of light oil with acid brush close at hand.

Since your mill is a manual vs CNC, you're going to be at the mill full time (no auto- pilot) anyway, it's no big deal to spritz or brush on a little coolant as needed.

Less mess......much safer.

Mike

timc

Linefinder said:

A misters best application is within an enclosed CNC when the computer controls won't "quite" allow you to direct the flow exactly where you need it. We have four in my shop. Three are still in the box, and the other has been collecting dust for 9 years. OTOH, everybody has a Windex bottle full of coolant and a small container of light oil with acid brush close at hand.

Since your mill is a manual vs CNC, you're going to be at the mill full time (no auto- pilot) anyway, it's no big deal to spritz or brush on a little coolant as needed.

Less mess......much safer.

Mike

Sounds like a plan!

Teach

A "Last Word" dial indicator is worth its weight in gold when squaring things up.  I've got a couple of them, with the associated adapters to mount therm in different locations.  Check out Ebay for good-condition used ones.  They virtually never wear out- - - - -they're more likely to get damaged due to careless handling than failing from excessive use.

Linefinder

Tim,

Just a bit of background......

I got tossed into this trade 8 years ago through no planning on my part. One day I was designing/drawing  parts for our toolmakers to make, and suddenly I was assigned to make them. That the transfer from theoretical paper to actual steel was sudden is to understate the situation. I didn't know the difference between a mill and a lathe.

Unfortunately, my mentor thought it was amusing to "let him figure things out on  his own". It's been a painful several years. The "simple" stuff isn't nearly as simple as it seems, and if you don't get that right, nothing subsequent will come out right.

I can bore you with simple things I've learned the hard way if you're interested.

Mike

Teach

You could spend a couple of hours of one-on-one conversation just on different alloys needing different spindle speeds and feed rates, and that's just for aluminum.  Add brass, steel, and plastic to the mix, and it really gets interesting!  Does anybody grind their own lathe tool bits anymore, or am I the only dinosaur that still does that?

 

Linefinder

Teach said:

You could spend a couple of hours of one-on-one conversation just on different alloys needing different spindle speeds and feed rates, and that's just for aluminum.  Add brass, steel, and plastic to the mix, and it really gets interesting!  Does anybody grind their own lathe tool bits anymore, or am I the only dinosaur that still does that?

 Yes, I do that, but it might take me three days to get one right before I can finish a 20 minute job.

Dressing a surface grinder wheel is usually involved, and I really suck at that.

But I work with a guy that can (no kidding) grind a .050" pin down to .030" and hold .0005'" tolerance. It might take him 3 days and 20 tries, but he'll eventually get it. That he can get it at all amazes me.

Mike

tennmike

Teach said:

You could spend a couple of hours of one-on-one conversation just on different alloys needing different spindle speeds and feed rates, and that's just for aluminum.  Add brass, steel, and plastic to the mix, and it really gets interesting!  Does anybody grind their own lathe tool bits anymore, or am I the only dinosaur that still does that?

 

I still grind a lot of my own tooling, and especially for the metal shaper operations. It requires hand grinding tools because of the reciprocating cutting method it uses. Normal tools won't work, and carbide is pretty much a non starter due to the impact of the bit on the work piece at start of the cut. Carbide doesn't like that impacting at all, and will chip the cutter immediately; I use a high cobalt tool blank hand ground to make the cuts, and with a radius on the leading cutting edge when possible to cut down on chipping the cutting edge on them.

I use a squirt bottle for cutting fluid application on mill, lathe, and metal shaper. Put it where I need it when I need it, and regularly blow out chips when milling to prevent cutter binding. Like Linefinder said, fly cutters are O.K. for some things where finish isn't important, but when it IS important, then the shell mills are the way to go. Hurts to buy them but they're worth it in finish alone.

Most plastics you'll run into milling will make you say words if you try to cut fast because the stuff is soft. Well, yeah, it's soft and when cut with an end mill it blows up like popcorn, You must clean it out very regularly or chancing the mill binding and blowing out the part you just spent a lot of time indicating in the vise and milling. Nylon, PVC, and Starboard plastics are what I work with the most, and they all require constant chip cleaning in pocket cuts.

Linefinder's advice on roughing mills with a radius at the cutting edges is right on the money as it saves on tool wear. Same kind of thinking between roughing and finishing reamers for chambers.

Squaring the vise to the X-Y of the table, and making sure the vise jaws are square to the quill will make for precision cuts. If the vise ain't square in X-Y-Z coordinates to the quill then nothing will come out right. DON'T scrimp on the indicator for this setup stuff, they last forever with care and make things way more agreeable to machine.

When making a dovetail cut for a 3/8" dovetail sight, use a regular end mill of around 3/16" diameter set to dovetail depth first. That will save you buying another not so cheap dovetail cutter when you break the teeth off trying to cut a dovetail with only the dovetail cutter, and when you are cutting the dovetail, go dead slow with lots of lube. Those cutter teeth are very fine on the ends and don't like rapid loading.

timc

Linefinder said:

Tim,

Just a bit of background......

I got tossed into this trade 8 years ago through no planning on my part. One day I was designing/drawing  parts for our toolmakers to make, and suddenly I was assigned to make them. That the transfer from theoretical paper to actual steel was sudden is to understate the situation. I didn't know the difference between a mill and a lathe.

Unfortunately, my mentor thought it was amusing to "let him figure things out on  his own". It's been a painful several years. The "simple" stuff isn't nearly as simple as it seems, and if you don't get that right, nothing subsequent will come out right.

I can bore you with simple things I've learned the hard way if you're interested.

Mike

timc

timc said:

Linefinder said:

Tim,

Just a bit of background......

I got tossed into this trade 8 years ago through no planning on my part. One day I was designing/drawing  parts for our toolmakers to make, and suddenly I was assigned to make them. That the transfer from theoretical paper to actual steel was sudden is to understate the situation. I didn't know the difference between a mill and a lathe.

Unfortunately, my mentor thought it was amusing to "let him figure things out on  his own". It's been a painful several years. The "simple" stuff isn't nearly as simple as it seems, and if you don't get that right, nothing subsequent will come out right.

I can bore you with simple things I've learned the hard way if you're interested.

Mike

Absolutely! I can use any and all help I can get. CPJ has taken me under his wing so to speak and has given me a list of what I need to get started as of a few minutes ago I have more in tooling and measuring devices by double over what I paid for the mill. So far the spousal unit is supportive.

timc

Lots of really good advice. I really appreciate you guys sharing your knowledge, this is something I’ve wanted to learn for a long time. With every new piece of equipment I add to the shop I feel closer to really enjoying retirement and starting my second career, you know the fun one where you don’t really care if you make any money at it because it’s just for pure fun!

Linefinder

If you delve into plastic, be aware nylon sucks (fuzzes up badly), as does PVC, (melts quick if your feed & speed is a little off). I do a lot of plastic and given the option I'll choose Delrin every time. Cuts clean, doesn't push much, and I've never melted an edge. Costs a little more, but worth the price.

Mike

Michakav

A good dial indicator on a solid magnetic adjustable base will be one of your best friends.

timc

Michakav said:

A good dial indicator on a solid magnetic adjustable base will be one of your best friends.

Got one ordered!

tennmike

Linefinder said:

If you delve into plastic, be aware nylon sucks (fuzzes up badly), as does PVC, (melts quick if your feed & speed is a little off). I do a lot of plastic and given the option I'll choose Delrin every time. Cuts clean, doesn't push much, and I've never melted an edge. Costs a little more, but worth the price.

Mike

Derlin is good stuff. I don't use it for one reason, though. I sometimes make a non functional model of a design just to test the idea out without burning through expensive metal when plastic will give me a 'Yes, it will work' or a 'No, it won't work' verification. If it works, then I go to metal and make the whatever.

And you are right  on the money about cutting and feed speeds with plastics. Too high a spindle speed and/or feed speed tends to give immediate feedback if you screw up either!

Aluminum and plastic 80% receivers will also give you an education on what can happen if you are lax on chip cleaning while cutting. Aluminum is just as bad about making 'poofy' swarf that will grab in the end mill and make a mess of an otherwise clean cut. I'll just say that with either the plastic or aluminum that 100 psi air and 50/50 mix of dish soap and water is your best buddy when cutting either. It's messy and you need a full face shield, AND goggles. Get a GOOD shop vac  because swarf from cutting anything will build up on floor around machine and cause a slip hazard, and I doubt any wives would like you tracking that mess in on floors and carpets. A good boot brush for mud/horse/cow crap removal gets most of it off bottom and sides of shoes, and you should check them before going in the house. Domestic tranquility is good. Plastic and metal shavings sticking on/in bare feet is gonna cause friction.

Linefinder

Joe Pieczynski

Check out his videos on YouTube. 

He's gonna soon be your best friend.

Mike

Linefinder

Before you stock up on material, here's a couple more tips......

Stainless steel.......303 machines "sorta okay". 304 and 316 absolutely suck for machining. 410 and 420 are much better choices for any machining operations.

Aluminum....I don't like aluminum for all the reasons Tennmike stated. Gummy, easily galls up cutters and an all around PITA. Doesn't take small delicate features very well. BUT.....there's an aluminum alloy called FORTAL that cuts as easy as aluminum, but will take features similar to steel. As to lubes for cutting aluminum, I really like Relton's A9 cutting fluid. Lacking that, I've obtained decent results with plain old iso alcohol.

Tapping compounds.....Lots of choices out there, but in my book the best by far is Cim-Tap by Cim Cool. Work's on everything and doesn't make a huge mess like Moly-D.

Mike

Linefinder

Oh...don't use iso alcohol on ferrous metals.....for obvious reasons.

Mike

timc

tennmike said:

Linefinder said:

If you delve into plastic, be aware nylon sucks (fuzzes up badly), as does PVC, (melts quick if your feed & speed is a little off). I do a lot of plastic and given the option I'll choose Delrin every time. Cuts clean, doesn't push much, and I've never melted an edge. Costs a little more, but worth the price.

Mike

Derlin is good stuff. I don't use it for one reason, though. I sometimes make a non functional model of a design just to test the idea out without burning through expensive metal when plastic will give me a 'Yes, it will work' or a 'No, it won't work' verification. If it works, then I go to metal and make the whatever.

And you are right  on the money about cutting and feed speeds with plastics. Too high a spindle speed and/or feed speed tends to give immediate feedback if you screw up either!

Aluminum and plastic 80% receivers will also give you an education on what can happen if you are lax on chip cleaning while cutting. Aluminum is just as bad about making 'poofy' swarf that will grab in the end mill and make a mess of an otherwise clean cut. I'll just say that with either the plastic or aluminum that 100 psi air and 50/50 mix of dish soap and water is your best buddy when cutting either. It's messy and you need a full face shield, AND goggles. Get a GOOD shop vac  because swarf from cutting anything will build up on floor around machine and cause a slip hazard, and I doubt any wives would like you tracking that mess in on floors and carpets. A good boot brush for mud/horse/cow crap removal gets most of it off bottom and sides of shoes, and you should check them before going in the house. Domestic tranquility is good. Plastic and metal shavings sticking on/in bare feet is gonna cause friction.

Tracking stuff in the house is grounds for immediate butt crunching! My wife has a back for finding any splinter metal or wood!

tennmike

Some of that metal and plastic swarf is tiny and hurts like crazy when it penetrates skin. And trying to get it dug out when it fully penetrates below surface skin level is an adventure in pain.

One thing not mentioned, yet, is climb milling. Learn what it is and why you should avoid it with a purple passion. No hobbyist mill can really be built rigid enough to withstand the forces involved. It will eat end mills like a fat kid with unlimited free candy.

Linefinder

I keep a pair of surgical tweezers (sharpened edges) in my toolbox and another at home. They usually work so you don't have to dig around with a needle.

Big Al1

When I started machine work as a hobby, I took a hands on machinist  course at the local Technical School, that helped a lot. I did grind my own lathe bits. I had to make a 55 degree bit for Mauser threads, and a square bit for #1 rolling block threads.

Teach

When I was welding a lot of thin wall stainless steel pipe in a winery, we squared up the ends of the pipes with a special tool before TIG welding them together without using any fill rod.  Those tiny slivers of stainless the truing cutter would produce were notorious for getting into the crease of a finger joint and working their way to the top of the knuckle before we could dig 'em out!   

Linefinder

6 years or so ago I got a tiny chunk in my finger that I couldn't get out. After it had festered for about 3 days I was able to squeeze it out. It was about the size of a grain of salt. Two days later I was at Urgent Care with blood poisoning. 4 trips to the doc in all. Luckily, it was a WC claim.

I take slivers very seriously nowadays.

tennmike

Linefinder said:

I keep a pair of surgical tweezers (sharpened edges) in my toolbox and another at home. They usually work so you don't have to dig around with a needle.

I have those tweezers, and some disposable scalpels with triangular and rounded blades purchased from Science and Surplus for those that get buried beyond the tweezers. I have no patience getting out the nasty solvent soaked hurties that bury themselves out of reach.

And being a redneck former farmer with lots of experience getting cut, scraped, stomped, stabbed, and otherwise gouged with stuff around the farm, I also have found good stuff (antibiotics) at the Farmer's Co-op that works on both farm animals and people for treating such boo-boos on the spot RIGHT NOW. What does not kill you makes you stronger. And LA200 antibiotic burns like hell on steroids, but sure is good stuff.

Might as well give one more suggestion for shop floor. I didn't really study the picture of yours, but I have a seriously worthwhile suggestion. Get epoxy garage floor covering for concrete in WHITE with none of those 'cute' little color chips in it. Put it down all over the floor. It makes cleanup of all those chips, swarf, and dirt a LOT easier, and the white color lets you see it. Makes the light you have available in the shop work better, too.

And buy or make a scraper tool for cleaning out the slots in the mill table clamping slots. They're a swarf magnet and MUST be cleaned out regularly for placing different vises and other work holding fixtures on the milling table. Easy to make one on the mill from a piece of 1/16" hot roll flat bar.

Linefinder

A decent sized magnet works well for metal chips, and can get up the bulk that pile up on the table before you brush them into the tee slots. The tee slot tool Tennmike mentioned is the only way to go for packed in stuff. Finish off with a short stiff paint brush in the slots.

As to cleaners for the mill itself, I see a lot of Simple Green used, but it's never impressed me much.  Zepp's purple industrial degreaser works like magic. It'll even make three days worth of burn residue in an EDM rig run off like water, and that takes some doing. Just be aware over-spray will remove grease/oil from parts you want greased/oiled.

Mike