drill/mill bit for slotting?

Mini Bike & Go-Kart Parts

markus

Well-Known Member
#1
I have a project where I need to make short slotted holes in some steel straps and aluminum pieces. I ran across a couple of sliding vices for a drill press and was wondering what the bit would be called or if they even make something like that to use in a drill press. I kinda did a quick search on mill bits, and not sure if they will hold in a chick or not???? I know nothing about milling machines or anything like that. just seeing if I can do the holes in house without spending way too much $$$.
 
#2
Drill press might not have the bearings for the side load that you want to place on them.
Depends on what you are trying to do
I thought I had read about people using a router with a special bit for aluminum?
Plasma cutter could work well too
 
#3
depending on how thin the metal is and how well it is held in place. a end mill just might work on a drill press. more then likely you might get some movement in the vise? not good and you will need to watch your speed on a drill press and the side load for the drill press can't take a lot,but for something like that it might? does the drill press have different pulley settings? slow is your friend and lots of cutting oil.
 
#4
depending on how thin the metal is and how well it is held in place. a end mill just might work on a drill press. more then likely you might get some movement in the vise? not good and you will need to watch your speed on a drill press and the side load for the drill press can't take a lot,but for something like that it might? does the drill press have different pulley settings? slow is your friend and lots of cutting oil.
Yup
“Feed and speed”
Or just cut it out with a plasma cutter, they make a nice clean cut. Can do steel or aluminum as well.
 
#5
Carbide burrs might work, standard 1/4" shank would work in multiple power tools. Get separate burrs for aluminum (ones for steel will plug up if used on aluminum) and steel. Drill a hole, use a burr to elongate the hole. As mentioned, use light pressure to avoid damaging drill press bearings; raising the table as high as possible (reducing extension) may reduce stress and chatter.

You could drill a hole at each end and connect them using a jigsaw, clean up using burrs, files, etc. Another option would be to drill multiple overlapping holes to remove most of the material, then clean up.
 
#6
I have a project where I need to make short slotted holes in some steel straps and aluminum pieces. I ran across a couple of sliding vices for a drill press and was wondering what the bit would be called or if they even make something like that to use in a drill press. I kinda did a quick search on mill bits, and not sure if they will hold in a chick or not???? I know nothing about milling machines or anything like that. just seeing if I can do the holes in house without spending way too much $$$.
Are the ends of your slots radiused ? If they are, drill each end and along the length. Remove the rest with a dremel. If they are exposed and finish is super important, a grinding point on a drill press with a sliding vice maybe? Light cuts and light passes.
 

markus

Well-Known Member
#7
Thanks guys, its a short slot and I have been doing them by drilling holes a each end and connecting whenever I was doing them in the past few years but its a pain in the ass since its too short for a blade, mostly dremel and file work. I may just have a run of them cut like I did when I had pieces cut for a batch of Lil Indian kickstands I made a few years ago, I just have to remake the tool I use in the press to shape the bracket......I was making the slot and cuts/lengths after the bracket wash bent/shaped so I need to get that more precise so the slot will be in the right spot everytime. I saw that bolt down mill table and got me wondering If there was a bit that I could use. the slot doesn't have to be precise, but I want them looking pretty uniform, I just want to make a final run like 25-50 of them and be done for good, I was making like 5 at a time before.
 
#10
I am not recommending you do what I have described below because you will be doing something with the wrong machine and the results could be deadly so remember you will be at your own risk, however with care and patience what you want to do can be done.

Endmills come with many different style ends on them. You have available balls, radius, cones, flatends with both center and non center cutting ability plus unlimited custom configurations. Plus different materials, HSS, Cobalt, Carbide.

A standard over the counter center cutting HSS mill has the same abilities as a drill in that it allows you to plunge down into your work. Use this mill much like a drill and first plunge down and thru your work piece then raise up out of the hole you cut and move your work piece over with your vice about half the diameter of your mill and plunge [drill] again. Do this same procedure until you have your slot length established. If need be you can lower down into the slot you have now established and do a very slow clean up pass using your vise.

Couple words of caution, make sure your vice 'ways' are quite tight and will not move freely without being manually moved, use High Speed Steel only endmills, and wear a good approved safety glasses.

O.J.
 

Oldsalt

Well-Known Member
#11
Thanks guys, its a short slot and I have been doing them by drilling holes a each end and connecting whenever I was doing them in the past few years but its a pain in the ass since its too short for a blade, mostly dremel and file work. I may just have a run of them cut like I did when I had pieces cut for a batch of Lil Indian kickstands I made a few years ago, I just have to remake the tool I use in the press to shape the bracket......I was making the slot and cuts/lengths after the bracket wash bent/shaped so I need to get that more precise so the slot will be in the right spot everytime. I saw that bolt down mill table and got me wondering If there was a bit that I could use. the slot doesn't have to be precise, but I want them looking pretty uniform, I just want to make a final run like 25-50 of them and be done for good, I was making like 5 at a time before.

The #1 problem with using an end mill in a standard drill press is that the drill chuck has a "Jacobs" taper. It has a rather high angle taper that is good only for pressure straight down....no side load that an end mill would need to make slots. The taper in a common milling machine is a lot more gradual...designed to accept side pressure AND it is held in place by a drawbar so it can't easily loosen. The whole chuck and end mill could [probably will] fly out of the machine with a Jacobs taper if anything but a vey light cut was attempted. #2 probable problem is that the little bolt down mill attachment that mounts on the drill press table is not rigid enough for anything but the lightest work...and then only in soft materials. Really great for wood. #3 is that the bearings in a drill press [designed for downward pressure only] will have far too much radial 'run-out' and chatter will be a big problem. As the distance from the lower beaing in the drill press quill is a long way from the work [unlike the short distance in a regular mill] the problem is really magnified. #4 is that the three jaw drill press chuck is far too little holding ability. An end mill has a habit of pulling its self out of even a proper milling collet if not well tightened due to the high helix angle of the flutes....especially when 'drilling' down with the flat end of the milling cutter. If you can use a 'larger than the usual home shop drill press' [one with a Morse Taper for the drill chuck] and get the gibs really snug on the mill attachment ways and take light cuts there are a couple of tricks for dealing with less than optimum rigidity. One is to use a 3 flute end mill...not a two flute. For cutting slots there is a lot less 'side to side' chatter developed. It will be almost absolutely necessary to pilot drill with a drill almost the diameter of the end mill to be used even if a 'center cutting' end mill is available. I think the little mill attachment is a nice thing to have for your drill press because they offer a method to get a series of holes drilled within a few thousants of their desired positions by using the dials on the X and Y handles. Use a small 'spotting drill' that has a 90 degree point to start the holes. Then use a regular twist drill once you have a good dimple for the twist drill to follow. A lot more accurite than laying out and center punching and then drilling because there is is very little 'drill wander'. Remember that if you attempt to mill the edge of a piece of material make sure that the cutter, when it engages the work with its cutting edges, 'pushes' the work away from the cutter. If the mill grabs a bite and pulls the work toward its self all 'slop' in the machine will be taken up and will allow it to instantly take a really BIG bite. Result: usually a broken cutter.
 

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