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Learning to run the mill, machinist help please

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Replies

  • LinefinderLinefinder Moderator Posts: 7,052 Senior Member
    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
    "Walking away seems to be a lost art form."
    N454casull
  • LinefinderLinefinder Moderator Posts: 7,052 Senior Member
    My opinion on climb milling isn't exactly the same as Tennmikes'. Using a manual mill, 90% of your cutting will (should) be conventional cutting. But, I use climb cutting for my last few "sneak up" cuts almost without exception. 

    To describe the difference.....here's the best I can do......

    Conventional milling....imagine driving forward with your wheels turning in reverse. This is the "normal" cutting method with a manual mill, and you can take your largest cuts using this method. The cutting edge of the tool throws chips away from the part.

    Climb milling.....driving forward with your wheels turning forward. You have to take smaller cuts, but the final finish is much better. The cutting edge of the tool throws chips into the part.

    If I am sidecutting, I use both methods. If I have stock 1.100" and I need it to be 1.00", I'll conventional cut .080" at (depending on the material) .020" per pass. After 4 passes, I'll mic the part, and say it actually measures 1.018". Okay....I'll move over one half that (.009") and CLIMB cut that pass. Theoretically, I should be at 1.009", but I measure again and I'm actually at 1.011" (due to different direction of rotation of the cutting edge). So, I'll approximately half the distance I need to go, and move over .006" and take another CLIMB pass. Measure again. and I'm at 1.005". I'll move over .003" and Climb cut again. Measure again. I'm at 1.0015" .Move over .001" and take TWO climb passes without adjusting the table between passes. Chances are good you'll be well within tolerance.

    The final climb cuts result in a better finish than had you ended with conventional cuts.

    Summary: Conventional mill your "roughing" cuts. When you're getting "close", switch to climb cut, and adjust each cut to half the remaining distance to your desired length.

    Mike
    "Walking away seems to be a lost art form."
    N454casull
  • TeachTeach Senior Member Posts: 18,428 Senior Member

    Just be sure your machine is rigid enough to do a climb cut, and the workpiece is clamped in TIGHT!  Most of the mill/drill machines in use for hobby work are just glorified drill presses and they're not rigid enough to do any high-load work.  A full grown Bridgeport or a big horizontal mill is a different kettle of fish.


  • timctimc Senior Member Posts: 6,684 Senior Member
    Teach said:
    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.
    Got one ordered along with everything else. All together I think I bought about $1,800 worth of tooling and instruments thanks to CPJ for emptying my bank account. I think I have a really good set up to start.
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • timctimc Senior Member Posts: 6,684 Senior Member
    tennmike 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.
    Already experienced some of that, wife dug one out of my toe, no more flip flops while working!
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • timctimc Senior Member Posts: 6,684 Senior Member
    tennmike 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.
    I do have an epoxy floor and a nice scraper to clean the channels.
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • timctimc Senior Member Posts: 6,684 Senior Member
    Teach said:

    Just be sure your machine is rigid enough to do a climb cut, and the workpiece is clamped in TIGHT!  Most of the mill/drill machines in use for hobby work are just glorified drill presses and they're not rigid enough to do any high-load work.  A full grown Bridgeport or a big horizontal mill is a different kettle of fish.


    It’s a beast!

    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • TeachTeach Senior Member Posts: 18,428 Senior Member
    edited May 2019 #39

    That "beast" is a drill press with a pretty good cross-slide table.   Search Ebay for  "Bridgeport" to see a real vertical mill.

    https://www.ebay.com/itm/CLEAN-2-HP-9-X-42-BRIDGEPORT-MILLING-MACHINE-CHROME-WAYS/163663328076?hash=item261b18334c:g:yIYAAOSw4EJct5gD  

  • timctimc Senior Member Posts: 6,684 Senior Member
    Hey I don’t want to lose my amateur status!
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • tennmiketennmike Senior Member Posts: 27,403 Senior Member
    The MAJOR problem with hobbyist mills is the slack in the leadscrews for X-Y travel. You need absolutely ZERO backlash when climb milling as the backlash lets the mill dig in and rapidly snatch the workpiece into the mill  cutting teeth. And that breaks milling cutters and ruins the workpiece. The backlash CAN be taken out by buying HIGH PRECISION lead screws and nuts, but you will pay three times the price of the mill for them. Mike (Linefinder) works with machines I'd easily kill people for! :D:D:D
      I refuse to answer that question on the grounds that I don't know the answer”
    ― Douglas Adams
  • timctimc Senior Member Posts: 6,684 Senior Member
    tennmike said:
    The MAJOR problem with hobbyist mills is the slack in the leadscrews for X-Y travel. You need absolutely ZERO backlash when climb milling as the backlash lets the mill dig in and rapidly snatch the workpiece into the mill  cutting teeth. And that breaks milling cutters and ruins the workpiece. The backlash CAN be taken out by buying HIGH PRECISION lead screws and nuts, but you will pay three times the price of the mill for them. Mike (Linefinder) works with machines I'd easily kill people for! :D:D:D
    I agree, I got the best I could afford and I think it’s not too bad for what I’ll be doing. 
    Ive decided my first project is going to be with an 80% Glock 26 with some custome slide milling. This will be my birthday present to me. 
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • GilaGila Posts: 1,828 Senior Member

    No good deed goes unpunished...
  • tennmiketennmike Senior Member Posts: 27,403 Senior Member
    timc said:
    I agree, I got the best I could afford and I think it’s not too bad for what I’ll be doing. 
    Ive decided my first project is going to be with an 80% Glock 26 with some custome slide milling. This will be my birthday present to me. 
    Tim, stay within the limitations of that mill and you CAN do good quality work! Just don't ask it to do things of which it isn't capable. And above all, HAVE FUN! Learning curve can be steep, so take your time, dope out the steps in your head/on paper; plan the work and work the plan. And, did I say, HAVE FUN???!!!
    With that mill, and a lathe, you can make some sweet tooling for working on firearms that are really expensive to buy, too. Stuff you've wanted and couldn't justify buying. And making YOUR OWN custom parts. Look how far CPJ came in such a short time. Have fun, learn, grow your knowledge. Youtube is your friend on lots of machining stuff. Search it out! The gun and gun tool videos will blow your mind and give you more ideas. And above all, HAVE FUN! :)
      I refuse to answer that question on the grounds that I don't know the answer”
    ― Douglas Adams
  • GilaGila Posts: 1,828 Senior Member

    No good deed goes unpunished...
  • timctimc Senior Member Posts: 6,684 Senior Member
    tennmike said:
    timc said:
    I agree, I got the best I could afford and I think it’s not too bad for what I’ll be doing. 
    Ive decided my first project is going to be with an 80% Glock 26 with some custome slide milling. This will be my birthday present to me. 
    Tim, stay within the limitations of that mill and you CAN do good quality work! Just don't ask it to do things of which it isn't capable. And above all, HAVE FUN! Learning curve can be steep, so take your time, dope out the steps in your head/on paper; plan the work and work the plan. And, did I say, HAVE FUN???!!!
    With that mill, and a lathe, you can make some sweet tooling for working on firearms that are really expensive to buy, too. Stuff you've wanted and couldn't justify buying. And making YOUR OWN custom parts. Look how far CPJ came in such a short time. Have fun, learn, grow your knowledge. Youtube is your friend on lots of machining stuff. Search it out! The gun and gun tool videos will blow your mind and give you more ideas. And above all, HAVE FUN! :)
    Fun is what it’s all about. I’ve always enjoyed tinkering with guns. Anytime one of my buddies has a gun problem I’m usually the first one they come to. I’ve done trigger work, hand made a part or two that couldn’t be found, stock work, this is just getting a Little deeper in. I’m within a few years of retirement and need a hobby to have fun with, maybe even make a little money at. Now is the time to learn and buy everything before my income is fixed. We will still be well off enough that making money at it is an option, not a need.
    ive already done some metal work, this clock is an example.

    I did this one for a friend as a birthday present for his wife who is from Gonzales, Texas.this is made out of 1/8” steel plate.

    we live just a couple blocks from a popular tourist area where they have a market once a month where everything sold has to be hand made by the vendor, so I have a market outlet for stuff like this if I want as well. Fun is first priority!
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • LinefinderLinefinder Moderator Posts: 7,052 Senior Member
    Tim,

    That clock is a very nice piece of work! Curious as to how you got such fine detail along the outline on the state border. In 1/8 plate that's impressive shy of equipment such as a CNC plasma cutter with associated software.

    You're gonna have fun with this.

    Mike
    "Walking away seems to be a lost art form."
    N454casull
  • timctimc Senior Member Posts: 6,684 Senior Member
    edited May 2019 #48
    Tim,

    That clock is a very nice piece of work! Curious as to how you got such fine detail along the outline on the state border. In 1/8 plate that's impressive shy of equipment such as a CNC plasma cutter with associated software.

    You're gonna have fun with this.

    Mike
    I gots some talent! LOL

    i have a Thermal Dynamics 60i plasma cutter but no table, I cut it free hand thank you very much. I do want a table and one is in my 5 year plan for finishing outfitting my shop.

    just to add, 1/8” plate makes for a fine clock face but you better hang it in a stud, Sheetrock ain’t gonna hold it for long.
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • timctimc Senior Member Posts: 6,684 Senior Member
    I made 6 others like it with our company logo for our departmental year end meetings and gave them out as door prizes to the guys. I can’t tell you how many have asked me to sell them ones like it. I had to turn them down because of copyright issues with our corporate logo but it was ok to make them and give them away. 6 clocks was $100 out of my pocket not to mention all the labor but it was worth it.
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • das68das68 Posts: 662 Senior Member
    timc said:



    good you have a steady hand

    couple of bad shakes


     whole different subcontinent

    goodness gracious me ;)

    very nice work







  • LinefinderLinefinder Moderator Posts: 7,052 Senior Member
    You did that free-hand. With a "torch".........

    I can't even draw a straight line with a pencil.  :'(

    Mike
    "Walking away seems to be a lost art form."
    N454casull
  • timctimc Senior Member Posts: 6,684 Senior Member
    das68 said:
    timc said:



    good you have a steady hand

    couple of bad shakes


     whole different subcontinent

    goodness gracious me ;)

    very nice work






    Very nice, I like it!
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • timctimc Senior Member Posts: 6,684 Senior Member
    You did that free-hand. With a "torch".........

    I can't even draw a straight line with a pencil.  :'(

    Mike
    Don’t feel too bad, you should’ve seen the first two I tried!
    🤮

    heading to the cemetery tomorrow morning,wife asked me to make a pedestal for this little Maltese she bought to put with the flowers on our daughters grave. Little labor of love. She loved animals and had two Maltese that we inherited when she passed.

    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • tennmiketennmike Senior Member Posts: 27,403 Senior Member
    edited May 2019 #54
    Tim, with your attention to detail you'll learn something NEW every time you make a cut with that mill. Just like any skill, practice will reinforce good habits, and cull the bad ones as they crop up. Hope to see some sweet gun project stuff in the next few months as you hit the ground running!

    And if you have questions, I'll do my BEST to answer here or in an IM. I have no secrets to keep about machining; I'll tell you what I know and give you some solid info on places to get information.

    Speaking of which, 'Machinery's Handbook' in print or on CD is something that will have you engrossed for a couple of years if you get a copy. It has info found no where else, and has just about everything machining related you'll EVER need. I recommend it MOST highly. Expensive in either form, but well worth the price.
      I refuse to answer that question on the grounds that I don't know the answer”
    ― Douglas Adams
  • timctimc Senior Member Posts: 6,684 Senior Member
    tennmike said:
    Tim, with your attention to detail you'll learn something NEW every time you make a cut with that mill. Just like any skill, practice will reinforce good habits, and cull the bad ones as they crop up. Hope to see some sweet gun project stuff in the next few months as you hit the ground running!
    Thank you sir! All the good advice you guys are giving me is a tremendous help. It’s nice to have a great place to go and tap into such knowledge. I’m greatful to you and everyone else who has and hopefully will continue to give me advice.
    its a lot to take in, my biggest enemy is a lack of patience. 
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • LinefinderLinefinder Moderator Posts: 7,052 Senior Member
    I don't consider myself a real machinist, much less a toolmaker. But, I know ONE thing for a certified fact and I'll fight the man to the death who disagrees.......

    The #1 attribute of a machinist/toolmaker isn't mechanical ability, or mathematical, or spatial skills.

    The #1 attribute is patience.

    When you have a tolerance of .002" or less, you've entered the land of gremlins. Speed isn't your ally.

    I used to wonder why a "2 hour job" occasionally took 3 days

    Now I know.

    Mike.





     
    "Walking away seems to be a lost art form."
    N454casull
  • LinefinderLinefinder Moderator Posts: 7,052 Senior Member
    To expound, I have spent 2 days setting up a CNC to cut a part that took 20 minutes to actually cut.

    Mike
    "Walking away seems to be a lost art form."
    N454casull
  • timctimc Senior Member Posts: 6,684 Senior Member
    I don't consider myself a real machinist, much less a toolmaker. But, I know ONE thing for a certified fact and I'll fight the man to the death who disagrees.......

    The #1 attribute of a machinist/toolmaker isn't mechanical ability, or mathematical, or spatial skills.

    The #1 attribute is patience.

    When you have a tolerance of .002" or less, you've entered the land of gremlins. Speed isn't your ally.

    I used to wonder why a "2 hour job" occasionally took 3 days

    Now I know.

    Mike.





     
    I’m getting there but it’s a struggle!old age is beginning to help, in a hurry is just not that important to me anymore.
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • TeachTeach Senior Member Posts: 18,428 Senior Member

    Try adding another zero to the right of that decimal point. The specified oil clearance on a Cummins Diesel connecting rod piston pin bushing is 0.0004".  I ran a boring machine at an big automotive machine shop that was capable of holding that kind of tolerance with a razor-sharp high speed carbide cutter bit, without doing any honing of the finished bushings.  Setting that one up to machine a set of six connecting rods with the exact same clearance on all of them was interesting!


  • timctimc Senior Member Posts: 6,684 Senior Member
    Teach said:

    Try adding another zero to the right of that decimal point. The specified oil clearance on a Cummins Diesel connecting rod piston pin bushing is 0.0004".  I ran a boring machine at an big automotive machine shop that was capable of holding that kind of tolerance with a razor-sharp high speed carbide cutter bit, without doing any honing of the finished bushings.  Setting that one up to machine a set of six connecting rods with the exact same clearance on all of them was interesting!


    Speeds bring up another question, I have the ability to change I think 6 speeds on my mill. How do I know what to use with say, milling a steel gun slide?
    timc - formerly known as timc on the last G&A forum and timc on the G&A forum before that and the G&A forum before that.....
    AKA: Former Founding Member
  • TeachTeach Senior Member Posts: 18,428 Senior Member
    edited May 2019 #61

    Figuring out the right speed/feed combination is something only experience can teach you.  If I'm working with a high-dollar workpiece, or something that's absolutely got to be done right  the first time, I'll try to find a piece of scrap with a similar alloy and do a few practice cuts at different feeds and speeds to see what gives me the smoothest finish.  Generally speaking, tough material like tool steel needs shallow cuts at medium speed.  Get too slow with the cutter, and it tends to grab and chatter. 

    I added a second motor, a jackshaft, and  and a Sprag clutch drive to my drill press to get a total of 24 speeds.  That one comes in very handy at times.

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