Since I havn't done much metal working thought I'd ask the pro's here. I need to make some cutting bits to work with on my wood shaper and I was wondering if you guys thing it's possible to do this at home. What I thought about doing is purchasing some steel and then using a die grinder to rough cut the "three identical" bits. Then I'd use my large drill press to clean then up and set the cutting angle. Is this possible? What metal should I be looking for that would allow for machining and then allow me to harden them?
A lot of woodworkers do this allready. Most use corrugated backed hss for the job. Nothing quite has the pucker factor of a shaper knife whizzing across the shop, Just remember the profile cut in the wood is at a tangent to the profile that you cut into the tool so that you may have to do some geometry to get a perfect match. You will have to buy some decent grinding wheels but it's not rocket science.
I think it's fair to call it possible, just not very practical. Getting three to look good is quite less challenging that to get three identically shaped, sharp, and balanced.
The guys I know that are looking for custom profiles are buying blank bits and having them ground by a CNC sharpening shop. At about $20 per grind, and whatever the blank costs, it's still much cheaper than the vet bills to fix the hole from one of these coming apart at speed.
Pretty much anything that you can get that can be hardened easilly at home will also get soft in a hurry as it heats up if used to cut while its a bit dull.
Starrett sells flat, ground, tool steel. This would work for what you describe, the hardening instructions are usually printed on the wrapper, and it comes in several types (air, oil, water hardening).
Tool supply outfits sell High Speed Steel tool blanks that could be cut up for a job like this and silver soldered to a base, then profiled. I suppose that with care, one could build a balanced single toothed cutter that could work pretty well, if at reduced feed rates.
This is a pretty simple job on a surface grinder, but that's not a tool you'd likely have in a woodworking shop.
If the steel is annealed first, you can glue (Locktite) and clamp all three bits together, and file your profile in them. If you use some hardened guide strips clamped to the face and back of the stack, it's not so hard to get all three blades to the same profile heights. You'll probably have to move the guides numerous times as you work along the profiles. This is similar to the technique machinists use with "filing buttons" and other similar hardened profile guides.
Then, of course, you must relieve the backs of the cutting edges. That can be done _carefully_ with a file, making sure you never quite file all the way to the cutting edge -- itsy, bitsy, gently filing right UP to the edge but not past, lest you change the profile. You'll find this is a much touchier job than the profile cuts.
Then you have to re-harden them.
Are you SURE it's not less expensive to buy the cutters?
I used D-2 when I made mine years ago. I clamped all 3 up in a vice at the major relief that I thought I wanted, then ground the form on my surface grinder. I came back and added more relief where I thought they needed it with a dremil.
Actually I'll be dong the work in my shop that has a large grinder, welders and air tools. But since I've never made bits I was wondering what the process was.
Dave, how did your bits stand up? What is D-2? I'm going to look at having them professionally made and also look at buying an assortment of bits that will get me the profile I want but was wondering if maybe I could do it myself.
My bits held up very well for a guy that didn't do much woodworking. I only made my own because I couldn't find the profile that I wanted.
D-2 is a very hard tool steel. It is difficult to machine before heat treat, after heat treat, you can't file it or use any conventional tools on it. I'm sure you could find some in Mcmaster-Carr. You could also use A-2 with similar results. Please understand that a surface grinder is not a hand held tool. It is a precision grinder. It would take some extreme craftsmanship to be able to make good blades completely by hand.
Whatever you make yourself will not hold up nearly as well as the carbide tools you can buy at the woodworking store.
I realize that I'm probably talking apples/oranges here - shaper versus lathe - but I have been successful in making lathe tool bits from cutoff pieces of auto and truck spring leaves.
I read about it in a magazine somewhere, and I have a friend who operates an auto/truck spring shop.
I was at his place one afternoon and mentioned the need for some some small cutoffs.
Before I knew it, I had about 20 pounds of near-square cutoff ends ranging up to three-inches in width and one-half-inch in thickness.
While I have a large number of conventional tool bits, one thing I have done is to grind a handle profile into one cutoff and I use it for a one-shot cut of an aluminum file handle.
My molder holds the tool at 25 degree angle to the cut so any dimension in the outward direction needs to be divided by the cosine of 25 degrees ie multipled by 1.1033 You can take the existing profile and miter cut it at the proper angle for your head, just trace it on the blank covered in blueing.
I rough the pattern into the blank using an abrasive wheel in a 14" cutoff saw, clean up with files and a 1" belt sander. Getting the final rear bevel right without messing up the profile is a pain.
I use A2 steel since it tends to warp less than the other tool steels when you harden it. This gets to be a problem when you are making a crown molding 5" across, the cutters are 6" long, weigh 6 or 8 oz. I hit it with the surface grinder after hardening and tempering to make sure it is FLAT before inserting into the head. My final hardness is around 57 Rockwell C. This is good for several thousand feet of pine molding without sharpening. (less for cherry of course!)
I'm going to figure out some prices and then see where I stand. If I need to purchase a small grinder wheel to use in my drill press to set the tapper / angle or what ever it's called what should I be looking for? Any idea's on balancing them?
Agreed. It's not that you can't, it's just tough to get good results. To do it right, you need to first make an EXCELLENT template to follow and they need to be cut similar to a key machine where the final grinding all matches the pattern (pattern follower system)...then of course balanced REALLY well.
A hunk of unbalanced steel spinning at 12,000 rpm will vibrate any clamping system loose in a hurry. They fly really well and do some serious damage also...good tooling for your enemies :)
I've read all the replies so far and I have a few questions: What is your shaper, shaft size, horsepower, RPM? What is the finished shape? What is the material? How many linear feet? Do you have shaper collars? 2-wing? 3-wing? Do you have a video camera?
I work in a cabinet shop ... We recently acquired a machine specifically designed for this task . It uses a mandrel that holds the shaper/molder head , and a 2D pantograph setup . It also has coolant flowing on the steel while grinding , and is set up to automatically give the correct bevel on the knives . We use corrugated backed HSS for most of our knives ... and all knives are balanced to each other . Unless you're looking for uncommon profiles , there are many places that sell preground knives . All things considered , if I were in your (Hotrod , not bamboo) situation , I'd buy them .
What is the name of the machine you are using? Model? I was at Busy Bee the other day and noticed that they have a 12" planner / mold maker that will take blades and am running the costs rights now to see if it works. I am interested in making my own blades though.
Fine Woodworking - in one of their books of collected articles - had a good article on doing exactly this, including how to calculate the shape to give you the right profile at the end. Geoff
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