Making a D-Bit Engraving Tool

[@oh8wingman]

So why did you choose to not relieve the trailing side of the tool as is standard practice? Seems to me if you are going to show the making of a "D" bit cutter you should at least mention it.

[@StuartdeHaro]

I did mention it.

[@StuartdeHaro]

9:43 in case you're interested.

[@oh8wingman]

@@StuartdeHaro My apologies. I was taking a phone call right about the time that came on the video. And for those of you who are interested, NO, I don't want my damned carpets cleaned...........

[@StuartdeHaro]

@@oh8wingman Yeah, but what about your car's extended warranty?

[@patheron7812]

I agree, without relief on the non cutting side, it is not a cutting tool. Of course it makes burrs, when the round edge is presented to the workpiece, it just rubs.

[@jimpritz4169]

Thank you for projects like this that can be made by those of us who have tools typically found in home shops.

[@aguycalledlucas]

Thanks for the video

[@angelramos-2005]

The content of this video is very interesting.You not just machine the tool but you heat treat it and use it giving a live to an otherwise anonymous passer-by.You can engrave with it.Thank you.

[@wires99]

Well, there's so much I can say about this video. I have a Cuttermaster, and I've been making these bits from carbide. I grind the cylinder in half first and then I put the conical tip on it. I also have the cam set that allows me to put a relief behind the cutting edge. Basically, it feeds the cutter harder into the wheel after the cutting edge to make a relief. Also, I have found empirically that grinding slightly more than halfway across the cylinder produces better results and fewer burrs in the work when you cut. I had a machining project that resulted in a lot of long, broken carbide and mills, and I have since turned them all into engraving cutters. Net net is that I have made quite a few engraving cutters, and I have tested them in aluminum. It's better when you're grinding the cylinder in half to go about .001" over and cut it a little small. Spin them fast and feed them slow and you'll get fewer burrs.

[@StuartdeHaro]

Thanks for the advice!

[@capman911]

You have also made yourself a tool post aligning tool to set the height of your cutting tools in the tool post holder.

[@bilbo_gamers6417]

some people recommend a very slight snap temper, just to relieve the internal stresses and prevent the metal from being super weak. a lot of the time fully quenched and untempered steel can be good. if your end mill is quarter inch or under though, in my experience, an untempered end mill can break extremely easily. but for something of that diameter, especially if you're drilling steel, you might not want to temper it.

[@StuartdeHaro]

Thanks for the insight

[@bilbo_gamers6417]

@@StuartdeHaro That's particularly for making a steel cutting end mill. It's very easy for O1 to lose its temper because of the energy required and heat produced from cutting steel. Brass cutting tools might lend themselves well to being tempered more. I'm not a metallurgist and this information is probably decently wrong but yeah generally when cutting steel you want to get your metal as hard as possible without it just snapping in half.

[@jpsimon206]

Stuart, I would not normally ask, but you have solicited viewers for questions. I just recently got a new jug of cutting oil that I am apparently allergic to. I stopped using it but found that I was now allergic to quite a few different cutting oils. I've done some research which is highly contradictory, but I have even read about machinists developing such a bad allergy that they needed to switch careers. I noticed you were using gloves, reminded me of the question. Can you share whatever insight you have on the subject? A lot of testimonials talk about arthritis like symptoms as well. I just want to make sure I can keep enjoying the hobby.

[@StuartdeHaro]

I have not run across anything like that, although coolant does irritate my eyes. Have you consulted a doctor about your symptoms?

[@highpwr]

Kewl. Maybe in a future video you can make a larger diameter version with a Morse taper shank. Half dead centers come in handy too sometimes.

[@kieren7763]

You could also do it without the lathe or mill take the relief cut first with a grinder but on an angle then grind the tip in I drill on a belt sander until the point meets the relief cut perfectly

[@jefflyon100]

Great video, still I'm going to be one of the jackasses that has to share his experience. Not sure why you didn't get atleast 62 plus rockwell. If using a torch I spend a lot of time bringing it to a black heat, 5 plus minutes minimum. Then take it the last few hundred degrees to above non-mag and hold it there for atleast a few minutes. Longer is better. Quench in oil, moving back and forth. O1 should always be tempered immediately, 300-350f in oven for two hours is good for cutting tools. Its hard to make a good tool without the back relief, its an absolute must. I machine to a point like you do, then hand grind the relief starting at the trailing edge and moving to cutting edge. Any relief if better than nothing. You don't need to be careful until you get near the cutting edge. If you can sharpen a drill you can do the relief. If needed put back in lathe and recut if tip is affected. Repeat steps until you've got your angle and relief if needed. I go pretty heavy with my reliefs. One its done a few passes with lapping paper or on a very fine stone (atleast 1000 grit) to put a tiny relief at the cutting edge (5-15 degrees) goes along way to making great cuts. Just a few swipes, it will be hard to even see it. They get better and more refined everytime you do it. You should add a relief grinding section to the video, tempering to.

[@JeremiahL]

Nice

[@jpsimon206]

One other video idea, I have always wanted the ability to mark things I have made with a custom logo. How does one go about making a touchstone, or Maker's Mark?

[@StuartdeHaro]

There are several ways to do this. Blacksmiths make custom stamps all the time. You can find that by searching for "making a touch mark". Another neat way is with electro etching. You make a vinyl mask of your logo and stick it to the part. Then you use a car battery charger to etch the part. Clamp one cable to the part and the other has a cotton pad soaked in salt water. Press the wet pad over the vinyl mask and whatever metal is exposed will get etched. It probably matters which cable is attached where, but I'm not totally sure.

[@bobstermer7058]

Good info. Can you use any high smoke point oil to harden steel?

[@StuartdeHaro]

That's why I used Canola. Peanut oil is also decent. Then there are the purpose built hardening oils like Parks 50, but that's not really a home shop kind of thing unless you do it a ton. Any oil will do in a pinch, just be prepared for smoke and maybe a fire.

[@StuartdeHaro]

@@BelieveontheLordJesusChrist Water generally cools things too quickly and increases the risk of stress fractures, especially around sharp corners. I'm not sure how wax or coconut oil would work. I'm assuming you mean that it would be melted first. It definitely needs to be a liquid so you can swirl the part around in it. Agitating the part keeps a vapor barrier from forming around it that would insulate it from the quenching medium.

[@bobstermer7058]

@@StuartdeHaro I liked the idea of using a metal paint can to hold the oil. If you drop a hot part, it won't melt through the can and the can lid can be sealed tightly which should slow down the oxidation process a lot.

[@milanmondal7851]

Try to give the cutting flute a relief

[@chrisstephens6673]

Just for a bit of fun, Canola oil in England is called Rapeseed oil. I guess the puritans were a bit prudish.😉 I don't know how different your O1 and our silver steel, but with silver steel you can quench in oil, water or brine. Oil gives a softer hardness but is better for crack reduction in complex parts. For max hardness brine is used as the boiling point is higher than plain water and so quenches quicker. Water gives a harder metal than oil and is the most convenient, but can quench too quickly for some shapes, which your D bit isn't Having written all that, oil hardness is obviously fine for your purpose ATB c

[@12345NoNamesLeft]

Your silver steel could be W1, or O1

[@StuartdeHaro]

Yeah. Rapeseed oil probably wouldn't exactly fly off the shelves here. I know silver steel and drill rod are among those terms where we are separated by a common language. Do they sell silver steel in different grades depending on the hardening medium or is it just one type of steel. Here we have the O series for oil, W for water, which can also be done with oil, and A for air hardening. There some others too. H13 is a high speed steel that will retain hardness at high temperatures. That's used a lot for tools that will punch or cut hot steel. S7 is very common for tools that will be struck, like jack hammer bits and cold chisels. D2 is a very common die steel that doesn't lose as much carbon when heat treated. This could probably be a video of its own.

[@chrisstephens6673]

@@12345NoNamesLeft strictly speaking we have just the one, which can be quenched in oil or water depending on the hardness required.

[@chrisstephens6673]

@@StuartdeHaro generally just the one. Simply speaking silver steel in the round and gauge plate, or ground flat stock, for rectangular. There are loads of other metals that can be hardened of course, the only real advantage of silver steel or gauge plate is that it is accurately(?) ground to size, for which of course you pay a premium. I put the question mark in because it being centre less ground is an accurate diameter but not necessarily completely round but trilobular.

[@chrisstephens6673]

@@12345NoNamesLeft just an add on to my last. Medium to high carbon steels can be hardened. As i understand it the other alloying elements refine the whole process. In the early 20th century you really only had a few steels to worry about and that is all most of us amateurs still need, saves a great deal of brain ache.😉

[@mslucass]

Wouldn't it be better to put the tool back in the lathe after milling in a four jaw and give it some back relief?

[@StuartdeHaro]

Yes probably. I wish I had thought of that.

[@frankacosta5446]

Might have showed the line you engraved.

[@StuartdeHaro]

I've got a video coming out next Monday showing the part. Stay tuned.