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More facemill exercises. Make you own for a buck.

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  • #16
    Neat idea Evan.
    Yep, Grade 8 bolts actually machine pretty nice even with HSS bits. I have so many left over from my car days I find uses for them now and then as stock for projects.

    Steve

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    • #17
      Drill chuck

      Was that drill chuck holding the end mill supposed to be in the picture. John b.

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      • #18
        Originally posted by john b
        Was that drill chuck holding the end mill supposed to be in the picture. John b.
        It did the job.

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        • #19
          Originally posted by john b
          Was that drill chuck holding the end mill supposed to be in the picture. John b.
          In the lathe ? Not much of a concern...

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          • #20
            I use my lathe chuck to hold end mills, drills, reamers, hones, smaller boring bars, whatever. I thought that was its purpose.......


            .

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            • #21
              Was that drill chuck holding the end mill supposed to be in the picture. John b.
              The problem with using a drill chuck to hold a milling cutter is that a 3 jaw drill chuck cannot be depended on to hold against side loads. In the application shown there are no side loads.
              Free software for calculating bolt circles and similar: Click Here

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              • #22
                Before things go off on the 'endmill in a chuck' tangent...

                Evan, could you post one or two more pictures from a different angle? Either the lighting is messing me up or I'm just not firing on all cylinders tonight (probably the latter)- I can't quite see the shape of the pocket milled out for the insert.

                Approaching DIY tooling from this angle is pretty nifty. It appeals to the cheap (not clumsy) bastard in me.

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                • #23
                  Here you are. It is just milled straight across parallel to the flats that are clamped in the vise. It's a good idea to put a clamp on the end of the bolt resting on the table.



                  Free software for calculating bolt circles and similar: Click Here

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                  • #24
                    Poifect, thanks!

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                    • #25
                      burned up end mill

                      Originally posted by Black_Moons
                      Wow evan, did you use HSS to cut that grade 8 bolt??

                      If so, what feed/speeds/DOC/WOC where you using?

                      I allways thought grade 8 bolts would be too hard for HSS mills/HSS bandsaws blades/etc and allways only used abrasives on them.
                      You are right Black Moons. I burned up a 2 sided 3/8 HSS end mill today trying to cut it. He must have used a carbide end mill as a matter of fact if you look close you can see it is one. I gave up after that. I'll make mine out of cheesey steel and maybe go to 1" bolt because I have a 1" R8 holder. The good guys at Fastenal gave me that 3/4" bolt , to bad I couldn't use it. Mine was extremely hard.

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                      • #26
                        Sorry you burned up a tool. Finding a bolt that hard is the exception. As I noted earlier I turned the pocket with a cheap HSS end mill no problem. I normally use carbide endmills for nearly everything including aluminum because the good ones (Garr in this case) are so good at holding an edge and are three times stiffer than steel.
                        Free software for calculating bolt circles and similar: Click Here

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                        • #27
                          Originally posted by Evan
                          The inserts are positive-positive so no additional rake or relief is required. That makes the project that much easier. About the only thing that is somewhat critical is accurate placement of the tapped hole. FYI, the inserts require a 4-40 holding screw.

                          Grade 8 bolts in that size are easy to machine since they don't cool quickly after forming operations. You might run into some that are too hard to work easily but that isn't very common. In order to meet the strength specification they must have a certain amount of ductility since they must be able to be stretched when installed. They cut just fine with HSS tooling as you can see from the pocket I made with a cheap end mill.

                          Someone was questioning whether you used HSS or Carbide. As you said above, you used an HSS end mill. I have cut grade 8 bolts with a hacksaw so an HSS end mill should work.

                          One more question kind sir. In drilling the hole to tap for the 4-40 screw, did you move in a bit from center.....say a thou or two to gain some additional pressure on the insert when seated and tightened?

                          Thanks in advance.

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                          • #28
                            Yes, move the hole very slightly toward the side wall of the pocket. But, be careful because the rake of the insert will make it possible to chip the carbide edge if it is clamped too tightly against the wall. If it is a bit too close a couple of swipes with a file will correct that. Better too close than too far as it's much harder to unmachine something.
                            Free software for calculating bolt circles and similar: Click Here

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                            • #29
                              A grade 8 bolt is not all that hard.
                              But, you do need proper feed and speed for machining this kind of steel. A light cut with to high of a RPM will quickly burn up and destroy a HSS endmill.
                              Even a little 7x10 mini lathe can easily part off a 1/2" OD grade 8 bolt with a HSS parting blade.

                              Steve

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                              • #30
                                Originally posted by Evan
                                Yes, move the hole very slightly toward the side wall of the pocket. But, be careful because the rake of the insert will make it possible to chip the carbide edge if it is clamped too tightly against the wall. If it is a bit too close a couple of swipes with a file will correct that. Better too close than too far as it's much harder to unmachine something.

                                Thanks. I'll do that soon.

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