how can I cut a keyway without a mill?

I need to cut a (roughly) 3mm keyway in a piece of 10mm brass rod and I don't have access to a mill. I do have access to most hand tools, though.
Can anyone recommend a way I can cut the keyway? I'm not too fussed about accuracy, as long as its within +/- 1.5mm of the nominal width I'm happy. Also, if it matters, it will be about 5mm deep.

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In your tools inventory,how about access to a lathe ?

the_mad_man (author)  steveastrouk6 years ago
I have limited access to a lathe, yes
Mount the shaft in the lathe headstock, and fashion a cutter, the same width as the slot, like a chisel. Set that to the centre height, and stroke it down the shaft, shaving the slot for you. Its even better if you can get a travelling steady on the lathe.

It will only take a couple of minutes of cutting to make aperfect slot.

the_mad_man (author)  steveastrouk6 years ago
sounds like a plan.
Only problem is making the tool, I'll figure that out later.
How about useing a few old files and elbow grease.
rickharris6 years ago
I assume you mean a woodruff keyway - traditionally they would be cut with a cold chisel of a suitable size. (often made for the task).

Drilling a series of holes in the rod will give you a good start - A narrow "cold chisel" can be made from a short section of industrial hacksaw blade ground flat at the end. or a broken or sacrificed drill suitably ground down.

You may get away with drilling a series of holes and using a slitting saw in a dremmel or drill press. A milling bit in a drill press may work if you make a way to hold the work solidly and feed slowly.

SagarL111 year ago

my e mail id is IN INDIA my mo. no. 9192255071418 & 9881257841

Portable Keyway Milling Machine (Available in 2 Models) Needs only 38 mm space on the end of shaft to cut new keyway, without dismantling the shaft from assembly. Cutting time for 25 mm wide, 12.5 mm deep & 150 mm long keyway is less than 15 Minutes. M/c makes a Keyway on a Ball Mill Shaft, while the shaft is in assembly. Sealed lubrication permits operation at any position of the machine.

Slide travel 150 mm
Vertical travel of spindle 35 mm
Min. shaft dia. 25 mm
Min. Shaft dia. for end mounting 40 mm
Max. Shaft dia. 250 mm

• Slide Travel (Longitudinal) 200 mm.
• Slide Travel (lateral) 50 mm
• Vertical Travel of Spindle 35 mm
• Shaft size 200-600 mm
• Max, width of Keyway 80 mm
• Min. length required for clamping 225 mm

Portable Centring machine.jpguntitled877.jpgIMG_20160312_132507.jpg
uneektalent4 years ago
Get a block of wood a little longer than the shaft. On a drill press, drill a hole in the end the same size as the shaft. If the drill bit is not long enough, cut off the part of wood that has been drilled, slide that onto the shaft, then continue drilling the wood untill you have enough blocks to cover the length of the shaft. Now, run it through the table saw lengthwise (using a carbide tipped blade and fence), cutting through one side of the blocks and partway into the shaft. Remove the blocks and clean up the sharp edges on the shaft with a fine sandpaper. You now have a straight, clean keyway. For a wider cut use multiple passes on the saw.
The "tool" can be an old screwdriver blade - they're hard enough to cut brass.
Burf6 years ago
Without knowing the configuration of the keyway, I would suggest that you might be able to cut it with a drill and some of the various cutting bits available for the Dremel Moto-tool.