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HSS saw setup on horizontal mill

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  • HSS saw setup on horizontal mill

    I want to split a 150 x 600 x 15 mm stock of mild steel lengthwise to get a 95 x 600 x 15 mm part and was wondering how to use an HSS saw in a horizontal mill to accomplish this. I have a 3mm thick, 200mm OD HSS saw with a 32mm bore. My milling machine has two shafts, 22mm and 27 mm. Here is how I am contemplating to use this saw: Use the 27mm shaft and make a mild steel washer to fill the gap between saw and shaft. Run the saw in a climb milling direction. Use about 300 rpm and very slow feed with coolant. Not sure whether I should make multiple passes or just one pass ... Does this sound reasonable or am I way off?

  • #2
    Taydin,
    I'd bet once you split that you'll find your two pieces are worse than a banana shape. But for my own piece of mind, I always make saw cuts like this in a few passes. It seems to allow for straighter cuts, but I could be just fooling myself. I'm not sure why you'd want to climb cut it though. There's no advantage other than helping to keep the material from lifting off the table.

    Pete

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    • #3
      Hi Pete, a few reasons for climb milling that I can think of. Have seen videos during my research on the internet, where milling cutters cutting slots were always being used in a climb milling fashion. The other reason is maybe the coolant won't be thrown all over the shop when I let it flow onto the cutting edge. Also, if the saw cuts from the bottom up, it will attack the stock in an unfavorable angle, because the cutting location will be wedge like and can cause a lot of vibration. Of course all of this is speculation on my part. This will be the first time I will use the horizontal spindle of my mill, so I am bracing myself for surprises ...

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      • #4
        Hi Taydin,
        OK yep you have some logical points I hadn't considered that's for sure. Like any mill, you sure as hell don't want anything to move though. Lot's n lot's n lot's of hold downs, then add one more after those just to make sure.

        Pete

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        • #5
          The saw won`t last long at 300rpm.Run it at 40 - 50 rpm and it will work fine.
          You will need to count the teeth on the saw to work out the correct feed rate for it.

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          • #6
            way off.....how did you you come up with 300? for any machining operation, remember rpm's= SFMx4/diam. SFM for mild steel is 80-100 when using hss...like Mark says, so that right down.

            Is the mill equipped for climb milling? If not, don't even think about climb milling on this or any other project, a wrecked cutter and/or bent arbor will result! Just clamp things sufficiently.

            Here's a similar set up, cast iron so its dry, but I'd do as you want in one pass with flood coolant. set up for a light chip, don't want to bust that thin cutter or rip through the key

            Last edited by Mcgyver; 12-25-2012, 11:39 PM.
            .

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            • #7
              Your 300 rpm will give about 6.3 x the recommended surface speed for mild steel with that 200mm saw. 300/6.3 = ~~ 50 rpm, which sounds reasonable, I'd probably cut it down a bit.

              You can set up the saw so it only slightly cuts through the bottom of the part, and then the teeth will be moving nearly lengthwise instead of trying to raise the part off the table.

              you obviously need to line up the part in the 600mm direction very accurately so as to get an accurate 95 mm all along it. I assume you have more than 700mm of table movement. If not, you need to make at least one "re-set" of the piece when partly cut, which can be an issue.
              1601

              Keep eye on ball.
              Hashim Khan

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              • #8
                Originally posted by J Tiers View Post

                You can set up the saw so it only slightly cuts through the bottom of the part, and then the teeth will be moving nearly lengthwise instead of trying to raise the part off the table.
                If he`s climb milling it won`t be lifting the part from the table.
                He needs to get the saw as far through the part as possible to give it the shortest cut path through the material,otherwise the length of saw engaged in the cut will be too much and give him feeding problems.
                If he`s got a shallow cut the number of teeth cutting at the optimum chip load may be enough to overload the machine and his setup.A smaller diameter cutter would be better unless he can hang the job over the edge of the table and get the cutter centre lower down.
                I also think he`s maybe only got a stub arbour to mount the saw on going by the diameters he has posted.It also seems he has no positive way of keying the saw to the arbour in which case he`s in more trouble.
                On an ideal machine a stub arbour with the saw properly mounted would be ideal as he could cut the job in one hit along the back of the table.

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                • #9
                  Thanks guys for the rpm warning. I will start with less than 50 and increase if things go smoothly. Regarding climb milling, how would I know if the machine is capable of climb milling? Here are some more measurements of the shaft. The length of the shaft is about 500mm. One end is a bronze bearing, the other end is an ISO40 horizontal spindle. The table length is about 50" and has auto feed in the X axis. The shaft diameter is 27mm, but I will be putting a washer to use this saw, which has a 32mm bore, so the saw seems to be more than what the arbor can handle. Assuming I use a slow feed (I'm in no hurry) and keep the cutting surface small by letting the saw stick out of the bottom by quite a bit, do you still think there is a bent arbor risk?

                  I will get some pictures of the arbor and the saw this evening.
                  Last edited by taydin; 12-26-2012, 06:00 AM.

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                  • #10
                    One thing about climb milling is that your cutter might be chipping into mill scale with every tooth. That isn't going to be good for it. You could make one pass conventional, which will lift the scale off instead, then climb cut to finish and push the scale off the other side. The teeth will never see the scale that way. Just a suggestion- I'm no expert.

                    You might also check to make sure you have enough teeth in the cut. You were talking about having the blade quite low- this will minimize the tendency for a climb cut to yank the material into the cutter, but it could also make a lot of vibration- also not good for the cutter, or the machine.

                    My first thought was as Uncle Pete said- you might end up with a couple of bananas if you make that long cut. I once cut into the end of some cold rolled flat bar for about 3 inches. The end of the cut splayed out to 1/4 inch. Blew my mind at the time. Imagine making that cut 2 ft long- the ends would swing out by 2 inches! Hot rolled is less problematic, at least in my experience, but there are still some stresses that will warp things.
                    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                    • #11
                      Have you got two overarm brackets to use with this arbour?
                      If you have I would mount the saw about 3" in from the drive end of the arbour,clamp the job down so the bit you want to cut off is overhanging the back of the table and wind the table up as close as you can to the brackets and cut it in one go.
                      You will be ok climb milling if the saw is well down through the job.
                      Put pegs in the back tee slot to push the job against to line it up parallel to the table.
                      Are you going to cut your 27/32 mm washer to get a key in?If the saw slips while feeding you will bend the arbour/break the blade.
                      What make of machine have you got anyway?

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                      • #12
                        Darryl, good point about the mill scale. Shouldn't be a problem to make a conventional milling pass to remove the top side scale. The bottom side scale will still be there, but hey, a gain is a gain.

                        Here are pictures of the 27mm arbor and the saw. Haven't looked whether there is a key slot on the harbor, will check that out. But the saw blade definitely doesn't have a key slot. Guess this means I will have to go extra slow to avoid blade slippage.



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                        • #13
                          Originally posted by darryl View Post
                          My first thought was as Uncle Pete said- you might end up with a couple of bananas if you make that long cut. I once cut into the end of some cold rolled flat bar for about 3 inches. The end of the cut splayed out to 1/4 inch. Blew my mind at the time. Imagine making that cut 2 ft long- the ends would swing out by 2 inches! Hot rolled is less problematic, at least in my experience, but there are still some stresses that will warp things.
                          I am going to be using continuous coolant, would that help reducing the thermal stress? Also, this part does not have to be super precise. It will be used as a rail for a bearing to roll on. (Think about the moving leg of a scissor platform). Maybe I should do a trial cut on a piece of scrap to get a feel about warping etc...

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                          • #14
                            if it turns into a banana its because of the stress locked in from the cold rolling process....the heat from cutting it isn't the issue, but flood is definitely preferred for all the other reasons to use flood.

                            The cutter has extremely fine teeth. Sometimes you have to use what you've got but I'd anticipate problems with it - use something coarser if you've got it. Here's a pic of the cutter I used - perhaps I'm making more chips than is accessory because of its width but I like that its big and solid and you can just let rip and properly load the arbor. Thin fine tooth cutters break easily and don't let you load the arbor properly.

                            Last edited by Mcgyver; 12-26-2012, 05:05 PM.
                            .

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                            • #15
                              Originally posted by Mcgyver View Post
                              The cutter has extremely fine teeth. Sometimes you have to use what you've got but I'd anticipate problems with it - use something coarser if you got it. Here's a pic of the cutter I used - perhaps I'm making more chips than is accessory because of its width but I like that its big and solid and you can just let rip and properly load the arbor. Thin fine tooth cutters break easily and don't lead you load the arbor properly.
                              That saw is really heavy duty! Almost like a milling cutter.

                              Also need to cut 50mm square tube almost lengthwise (about 7 degrees or so), so got this 200mm saw with the hope of having one saw that covers all cases. I'll report back the results.

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