Made a Carbide Tool - Oops!

[Chris Stolicky]

So, I finally made my version of one of the name brand expensive carbide insert tools. Actually, I have made another one since, and other kinds are in the works. Anyway, below are a few pictures of it before, and then after I broke it.

Be warned, these things are very grabby. It is my fault it broke (who else?). I was working on the tenon of a ~14" bowl and had the tool over 4" from the tool rest. Next thing I knew, I had the handle in my hand and the rest of the tool was sitting on top of the shavings. :eek:

The handle was walnut and cherry. Hey, the glue joint held!

[David E Keller]

Nice looking tool... Before it broke. It seems like the tang doesn't extend into the handle far enough and that may be the reason it failed. Four inches is a pretty good reach but I think it might have survived if the metal extended further up into the handle. Where did you get the bar stock for the tool? I've been thinking about making something similar

[Harvey Ghesser]

Chris,

I agree with David. I think the shank should have gone in to the wood a minimum of 2 inches. That would have prevented the break. JMHO.

Harv

[Steve Schlumpf]

I will agree with seating the tool deeper into the handle because that will be the weak point. Glad you didn't get hurt!

[Kyle Iwamoto]

Did you make a square hole? That would introduce a lot of stress points. Round hole and filler stock would be better. Looks like you had 2 inches of depth from the pics.

[Reed Gray]

You do want about 2 inches into the wood like others have said. Also, there is minimal wood around the tool and a bigger ferrule would have helped also. Another thing about the square hole. Make a 3 piece handle, one center piece and two outside pieces. The center piece is the exact same thickness as your tool shaft, and and you cut out a square hole for the tool shaft. The outside pieces sandwich the center when you glue up. Works really well.

robo hippy

[Norm Zax]

All already said but joining parts query - carbide tip and bar. Can you point us to the site? Thx!

[Jeff Nicol]

It was a nice tool and all the responses are spot on! The shaft should be in my eyes at least 3" in the handle. You were correct in saying it was your fault by having it hanging over the rest 4"! Very naughty of you!!

To answer others on where to get square stock, just about any hardware, bix box, or hundreds of sites on line cab provide it. I get mine at Fastenal as it is close to home, and at a Farm and fleet, or Menard's store. But my biggest supplier is a welding and manufacturing company in town that sells all types of steel and pipe. Lots of times they have remnants that the sell by the pound and it is pretty cheap.


Good luck and stay safe,

Jeff

[Chris Stolicky]

I'm just thankful the rotation of the wood pulls thing downward...

The steel is 1/2" square stock I found in the scrap pile at a steel store. It cost $0.50 per pound. You can also get it at your local big box store. I just cut and polished it with an angle grinder, and did other shaping work with my bench grinder. After purchasing the taps, the actual material for these is less than $10.

The shaft was inserted roughly 2" into a 5/8" hole, and then shimmed with thin pieces of wood and epoxy.

It broke at the bottom of the ferrule.

I think what I have learned here, besides getting better at tapping steel, is that I should insert the shaft deeper into the handle. These things can really take a beating. They are essentially scrapers and if you get too big of a bite, well you know what can happen there.

I have one in the works where I have used a 5/8" shaft and just tapered it towards the tip.

As far as carbide source, you can purchase both R2 and R4 inserts from woodchuck-tools. That is where I bought the R2 inserts. I actually ordered a pack of 10 of the R4 inserts from Globaltooling (their 'web special'). Just Google the names.

Its fun and rewarding to make your own tools. I think the tools itself is plenty strong, I just should have more of the tang in the handle, and be more cautious going that far over the tool rest.

One note - I meant to thank Chris Rae in my original posting for her help when I was planning to build these tools.

[Scott Lux]

Dang! that was a pretty handle too. It can be re-purposed for a mini-carbide tool now!

[Chris Stolicky]

Dang! that was a pretty handle too. It can be re-purposed for a mini-carbide tool now!

Yeah, I was just looking at that. One of the cracks goes back about half way. I may try to salvage what I can out of it. It will be a challenge re-drilling it now though.

I really need to build a spindle support one of these days. That would make things a bit easier.

[Dave Mueller]

Chris,
One thing to consider is that the commercial Easy Rougher has a round tang, not a square one, re: Kyle's comment above. Also, you might want to use a larger ferrule so that there is more wood extending out from the handle into the ferrule. I bought the Easy Finisher, which has a round carbide insert and it doesn't seem to be "grabby" at all. Maybe the round cutting surface doesn't present as much cutting edge to the wood. Finally, I made a similar round carbide tool but the carbide insert has a slight "dish" on the top more like a Hunter carbide. It seems to be more grabby that the Easy Finisher, which has a dead flat carbide top.

Regardless, glad the only thing hurt was the handle!

[Don Orr]

That was nice-for awhile. Glad you were not hurt. Sounds like you have the problem figured out for the next one.


And thanks for the wood.

[Norm Zax]

Reading your construction details Im quite sure 80% of the blame is on the hole design. If you need to shim a hole it is way too large and will take the beating much more roughly. It should be a smooth or even slightly tight fit. Try rounding the tang next time or using a round bar with a flattened side. Nice work!
Norm

[Chris Stolicky]

Reading your construction details Im quite sure 80% of the blame is on the hole design. If you need to shim a hole it is way too large and will take the beating much more roughly. It should be a smooth or even slightly tight fit. Try rounding the tang next time or using a round bar with a flattened side. Nice work!
Norm

I guess it wasn't very clear in the description. A 5/8" hole was actually a very tight fit. The shims filled small spaces between the flat part of the tang and the edge of the round hole. All 4 corners were tight to the edge of the hole. I actually rounded the shims to fit the arc of the hole.

A round tang would be nice, but my only option without getting too crazy, not having a metal lathe, is to use the bench grinder. I do have a tool in the works that uses larger stock that I knocked off the corners of using the bench grinder. It is more of an octagon shape now.

I agree that the weak part is the thin wood near the bottom of the ferrule. Hum, something to ponder, a slightly smaller tang, or a bigger ferrule? Maybe just knocking the corners (making it more round) off will enable 1) more direct contact of the tang with the wood, and 2) the ability to have a smaller hole, resulting in a bit more wood at the bottom of the ferrule. I believe the Easy Rougher (since it was mentioned above) is a 1/2" shaft with a rounded tang. Under that design, my theory would probably work.

Thank you for the input.

[Chris Stolicky]

That was nice-for awhile. Glad you were not hurt. Sounds like you have the problem figured out for the next one.


And thanks for the wood.

That's fine. I'll make another, improved, version. I just hope everyone can learn from this.

Your welcome. I'm working on making space in the garage before it snows, a little bit at a time. Although I still managed to come home with wood last night - just a little less volume that I left with...:rolleyes:

[William Payer]

Chris,

Looking at your photos , I would suggest the original diameter of wood/ferrule was far too small. The smallest distance from the tang of the tool to the ferrule is at the four corners, and it appears there is virtually no wood to support the tool in these areas. The lack of substantial wood in the ferrule area caused the wood/ferrulel to act as part of the tool shaft rather than part of the handle. In essence, you only had support in the part of the handle after the ferrule.

I have an Easy Rougher and the instructions caution against having any overhang over the tool rest greater than 1/2". Keeping the overhang this small, there is very little force put upon the handle/operator. There is a lot of leveraged force once you extend it out away from the tool rest. One user on a similar forum had his too rest snap when he got a catch (he had the tool over extended too).
Glad you were not hurt and the situation can be salvaged by turning another handle.

[Dave Mcintire]

I have an engine lathe and can turn the shaft round for a nominal cost if you would like - send me a PM. ALso, I usually leave 4 inches for inserting shank into the handle or 5 inches on larger tools. I turn the shank with a nominal .01 interference fit and never had one come loose, although some woods will crack when forcing the tool shank in the handle. The solution to that is to use ash for the handle and I never had a problem after that.

[Ern Reeders]

Why not mount the bit on round bar to begin with?

Then you can roll it for a shear scraping angle.

[Chris Stolicky]

This is a great thing about this forum - some conversations become a idea generating process....

As for turning the shaft round, it sounds nice, but my goal is to see if I can make tools myself. Sounds stubborn, huh? I appreciate the offer.

As for Ash, its funny you say that. I just bought some 8/4" ash for the intended purpose of my future handles. I think I will definitely combine many of the recommended improvements and discussions above.

As for the round bar.... I actually have a couple tools in the works that have a similar design as the Sorby shear scrapers. It is basically a square shaft with the cutter mounted at a 45-degree angle. I suppose a round bar could work too if you can control the rolling well enough.

[Ern Reeders]

The small Sorby multi tool uses a half round shaft which is neat. The flat for when you want to use the tooth pick and the round for shear scraping on the teardrop scraper. Control is no problem since the leverage forces aren't high.