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All -
I mentioned this in a post a few days ago, and although nobody expressed direct interest in it, I thought you might still like to see it.
I needed a reamer for a specific taper, and didn't even dare to check how much one might cost, so I decided to make one. It was the first real use of my 4th axis table.
The interesting thing about it is that if you actually think about making one, you'll realize that you don't need to turn the taper into a cone first. You can just start cutting the backs of the teeth (which is the same cut as the face of the previous tooth) and when you get all the way back around (in my case, six teeth total), index around another eight degrees and rough in the tooth relief at the tips. Once I realized that part, the G-Code got pretty simple.
After a little bit of cleanup with a file, just harden it, temper it, and stone the teeth to bring them to a sharp cutting edge.
This one is made from water-hardening tool steel from Enco. I did get a bit of warpage during the torch heating and quenching, but it is not a problem for my application. I have reamed several pieces of aluminum and bronze with it, and it is still in great shape.
You may also notice that I couldn't resist the urge to engrave the shank. I followed the directions in the Tormach manual, and it worked just fine. I used a 90 degree vee-mill just a few thousandths deep.
Enjoy!
- Just Gary
Looks Great! That's a very interesting application for the 4th axis. Interesting how we tend to over complicate things at first. I always say the most refined designed is the simplist.
I ordered a rotary table the other day and want to start building y 4th axis soon. I have the motor and drive already. I hope I can find as much use for it as you seem to have.
A universal dividing head, even operated manually, is a more versatile piece of equipment for making your own one-off cutting tools.
Phil
Originally Posted by saabaero
Sure, until you decide you'd like helical flutes.
If you really need to tilt the 4th axis, use a sine plate. If you need a tailstock with your tilting 4th axis, put the whole mess on another rotary table, or equivalent fixturing and rotate it about the Z instead of the Y.
And indeed, I wish I had made this one with helical flutes. My machine was only a few weeks old at the time, and I needed the reamer and wanted to try out the rotary table anyway. I decided to go for a high probability of success and make straight flutes.
The problem with straight flutes, of course, is that the chips make absolutely no effort at moving out of the hole, even with coolant flowing through. I end up using essentially a peck drill with a pause to wipe the reamer off. I have to go slowly to gauge the small end of the hole anyway, so while it is a little frustrating, I can deal with it.
Chatter does get worse near the end of the cut when the flutes are fully engaged, but so far I have managed to control it.
I have considered making another one, and I would go ahead and try helical flutes this time. Hand dressing helical flutes is a bigger challenge, so I think I'd program the final sharpening pass using a stone in the high speed spindle and let the Tormach do that too.
I also need a tool to make an undercut in a part, and I had thought about putting two upcutting and two downcutting helical flutes on it to enable it to easily cut at the top and the bottom. Of course, straight flutes would do it, but where's the fun in that? I'll put it on the list of things to do...
Regards,
- Just Gary
I made this 1/4" diameter simple toolmakers reamer from oil hardened drill rod. http://i72.photobucket.com/albums/i1...uff/reamer.jpg
Heated with a common propane torch and quenched in oil.
Also made this 5/16-11 tpi double start tap from drill rod but didn’t harden because it is used to tap Turcite.
http://i72.photobucket.com/albums/i1...leStartTap.jpg
-Don
Is that what that is? I made a tool like that which I use for deburring cross-holes down in a bore. I had no idea it could be used as a reamer!
Randy
Randy,
Yes that is what's known as a toolmakers reamer. Easy to make from drill rod or drill blanks and works great. Guy Lautard shows how to make them in "The Machinists Bedside Reader" ISBN 0-9690980-2-2 p.53 "http://www.amazon.com/Machinists-Bedside-Reader-Guy-Lautard/dp/0969098022"]Amazon.com: The Machinist's Bedside Reader: Guy Lautard: Books
BTW Guy also mentions that the 1/4" toolmakers reamer makes an unbeatable manicure tool. Also since the cutting surface on a toolmakers reamer is quite simple to make a good reamer can be made from HSS drill blanks on a grinder and hand finish honed with a stone, so no hardening needed.
-Don
Last edited by Don Clement; 03-21-2009 at 10:54 PM.
Don -
Thanks for showing that "deburr cross-holes down in a bore" tool. Oops, I mean reamer (just toying with you, Randy). The simplest tools usually are the best ones, and I really like anything that I can make in a few minutes and get the job done.
The tap is a great piece of work, too. It's hard to convince yourself to attempt hardening a tool if you don't need to, but I have found that the cutting edges will get so much sharper after hardening that it is worth it even for use on mild stock.
Regards,
- Just Gary
No slight intended on your own reamer, Just Gary! Not having ever done 4th axis work (and not having a rotary axis...) I would not be qualified to even comment on it.But I can tell it is a nice piece of work. I must admit that I'm impressed with your "just harden it, temper it" phrase--heat treatment is something I have no experience at--sure I've heated a tool red-hot and plunged it into a can of old oil, but the tool came out glass-hard and only lasted until it chipped.
Randy
Randy -
Absolutely no slight taken on the reamer. I was poking at the concept of "gee, I made one of those years ago to do that, but never really thought about what to call it." In other words, you were making and using reamers but not really thinking of them as reamers since you were *only* deburring with them. That's probably what I love most about making (and fixing) things. You have to figure out what you want to do and then make it happen some how.
The "harden it, temper it" thing was definitely tongue-in-cheek. I figured that someone would pipe up about how dumb I am for even trying it, but it turns out that blacksmith books are full of things just like that. If the tool really matters, you can get all sorts of technical with temperatures, soak times, and quenching baths. But for home shop use, the seat of your pants will take you a lot farther than you might imagine.
About a month ago I helped my son change a Welch plug on the front of an engine (in a van, no less). We tried the poke and pry method, but it would not budge since we didn't really have a lot of room for the pry part. I walked out to my shop and cut a short piece of drill rod, ground the end into a sharp but tapered vee (like the simple reamer but with two faces), quickly hardened and tempered it in a propane flame, and the tip broke on the first whack. I reground it, tempered it a little hotter, and proceeded to use it to easily lift the edge of the plug away from the block until it caved in. About five minutes each of toolmaking and plug caving. The point of all of this is that sometimes you just have to stop and think about what would work, then go make it. Well, and to remind myself that antifreeze does more than control freezing (which we don't have too much problem with here in Florida).
In your case, you got the harden part right, but forgot to temper. Since I discovered the toaster oven I only try to temper in a flame if it is a real quickie one-off tool like the punch above. For 1/2" and smaller drill rod, the toaster oven set on broil will eventually get the part to 450 degrees or so. Slow is good anyway, so you can watch it happen and quench when it is "just right." You can easily watch the colors on a bright surface, so I usually harden, then sharpen, then temper, then sharpen again if needed. If the cutting edge is too small to see, I use 800 (or so) grit paper to remove the scale and bring back a bright patch before tempering.
I usually aim for medium straw color, which will give a tool a decent balance beween hard and durable. If it is a hard-to-make tool, like the reamer, I will go a little hotter, into a light bronze. That will cost a little more hardness, but help insure that the tool doesn't break or chip too easily. Decent tool steel gets darned hard anyway, so you have a lot of room for error.
Try it! Grab a piece of drill rod (it really is pretty cheap; flip to the back of the Enco flyer and add some to your next Atrax endmill order) or carbon steel and harden it (just like you did before; red hot and quench). Test it with a file to make sure it is hard. Now sand or stone or buff it to bring a shine back to it, and slowly heat it and watch the colors. Even with a flame it won't take much practice to get it a light straw color (at the cutting edge) before you quench it again. If you get it anywhere close to straw color, a file still won't cut it. But now you can pry or beat on it and it will take it.
The Complete Modern Blacksmith is a pretty good book, and contains a short chapter on hardening.
Don't forget to post pictures of your work!
Regards,
- Just Gary
Randy -
By the way, are you actually a streamlined cave-man? Or are you just an old relic that still has that great art-deco look? I've always been a steam fan, but the Zephyrs were pretty cool. It's just that with something like a Hudson, you got streamlining and art-deco combined with all of that visible motion!
Regards,
- Just Gary
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