What kind of HSS cutter is this?

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Maplehead

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I bought a set of these a while back and I'm now trying to use a smaller one for cutting a t-slot in mild steel. I turned the shaft behind the cutter to be 1/8" straight, not tapered, and I made the slot for the shaft slightly bigger than 1/8". However, as soon as the cutting head got halfway in it got massive resistance and I feel if I try to turn the wheel harder then I'll break the cutter. I understand the cutter is getting resistance now that it's cutting on the traditional and climbing edges but it should still be much easier too cut. Is this bit just for straight slotting and not t-slots? I'm thinking yes since the shaft is tapered.
 

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I think that it is just a shaft slotting cutter. It's not made to be buried in steel to cut T-slots.
 
That cutter is called a Woodruff keyseat cutter, used to cut keyseats for Woodruff keys, they can be also used to cut straight keyways in shafts. T slot cutters have side clearance, Woodruff cutters do not. It is usually possible to cut tee slots with them, but maybe not with tiny ones such as you are using.
 
benmychree said:
That cutter is called a Woodruff keyseat cutter, used to cut keyseats for Woodruff keys, they can be also used to cut straight keyways in shafts. T slot cutters have side clearance, Woodruff cutters do not. It is usually possible to cut tee slots with them, but maybe not with tiny ones such as you are using.
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I'm not sure what size the key seat cutter is in the picture, but I have modified a few over the years to cut T slots. The smallest was 1/8"x 1/2". I could have purchased a proper T slot cutter, but I had several 1/8"x 1/2" woodruff cutters in stock. I ground down the shaft on the surface grinder for clearance and went to town.
 
projectnut said:
I'm not sure what size the key seat cutter is in the picture, but I have modified a few over the years to cut T slots. The smallest was 1/8"x 1/2". I could have purchased a proper T slot cutter, but I had several 1/8"x 1/2" woodruff cutters in stock. I ground down the shaft on the surface grinder for clearance and went to town.
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I did that as well but it won’t cut
 
This is the cutter in you pic

305 is a size for woodruff key cutters.

It was probably getting tight due to a combination of swarf buildup in the slot and the cutter heating up and getting bigger. Since there is no side relief it just got tighter and tighter.

To cut a T slot you have to be sure that you are clearing out the swarf and you should grind in some side relief on both sides of the cutter, and go slow. best with coolant, even if it is just a mist cooler.
 
Maplehead said:
I did that as well but it won’t cut
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The cutter will only cut the top cross bar of the T. In my case I cut the width of the vertical part to the proper depth with a standard 3/8"" end mill. Then I ground 1/2" of the shaft of the key seat cutter down to a little under 3/8". Next I put the key seat cutter in the collet and set the depth and made a single slow pass through the vertical cut to form the T cross bar on the bottom. In my case I did 4 slots 3/4" long. I doubled them up in the vise so the total length of cut was 1 1/2" each time.

As mentioned you might be loading the cutter. A standard T slot cutter has fewer cutting edges and they are angled so one leads with the top edge and the following one leads with the bottom edge. I was cutting 6061 aluminum and using WD40 as a lubricant.
 
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Typically tee slot cutters have staggered teeth.
 
benmychree said:
That cutter is called a Woodruff keyseat cutter, used to cut keyseats for Woodruff keys, they can be also used to cut straight keyways in shafts. T slot cutters have side clearance, Woodruff cutters do not. It is usually possible to cut tee slots with them, but maybe not with tiny ones such as you are using.
Click to expand...
What he said
 
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