Making a Harpoon. (Straight Hollowing Tool) post finished, look

[curtis rosche]

Here is the hollowing tool that I made, part 1. This is the easy one; it is simply straight for deep hollowing of simple shapes. I started by buying a steel bar and a pack of cobalt cutters. Then I realized that the cutters I got were slightly to big for the steel bar that I got. So I found a piece of steel in my junk pile, and it was the perfect size. It also worked well because I could not fit the steel bar under my drill press. I made this tool to fit in the 5/8ths end of my One-Way tool.
This may not be the best way to do it, but it is how I did it. Use your own common sense if you use my example to make your own, dont do anything unsafe.


Materials: (I do not know prices as I got all of these free, someone else paid for the bar, and I already had the others from scrap)
48 inch 5/8’’ round steel bar
2 1/8’’ set screws
1 piece of 1x6’’ mild steel
set of 5 3/8x3'' 10%cobalt steel cutter inserts. $25
So here it is step by step.

Step 1
Get the steel bar and cutters, cut the steel bar to the length that you want. I cut it to 24 inches, as that was the length that I could put into my handle and have the stick out be the same length as my gouge.

[curtis rosche]

Step 2
Realize that your steel bar is to small and then go find a bigger piece. The piece I used is 6 inches long and 1 inch square. The holes in the side of it are there from the previous use as an axel. However, the holes did help clear the shavings while drilling. I then chucked the piece up in the vise. Set a level on the side and top of the metal to make sure that your hole will be straight down. Also, put the level on your drill bit to check that too. Start with a small bit, around 1/8’’ but go with an off size so that if something goes wrong, you will not be out of a common size bit. But use the size you need for the finished hole. Then drill through half way, or as deep as your drill bit will allow. Then go to the next size drill bit. From 1/8’’ to around ¼’’ then to 3/8’’ then to ½’’. (NOTE: make the cutter hole between 1/16 and 1/8 smaller than the diagonal of your cutters.)
Then flip the piece over and do the same thing on the other side, but go to a 5/8’’ hole. I did that at school because I do not have that size bit at home. Adjust your hole size based on your cutter size and your bar size.

Use lube when drilling, and clamp down vise.

[curtis rosche]

Step 3
Drill 2 holes for setscrews on the end that will receive the steel bar. Then use a tap and die set and tap the holes for the setscrew. Sorry for the lack of pictures of this part. I forgot.
After you make them fit, take your steel bar and put a slight flat on the side that the setscrews will be.

[curtis rosche]

Step 4
Put the piece of steel you drilled the holes in a vise, and take your cutter bit, use something soft (a regular hammer will not work!!) I used a small piece of left over apple log. Make sure it goes in straight.

[curtis rosche]

last
Step 5
Sharpen the cutter. Then put the steel bar in the other end. And go use it.

[Mike Stephens]

Go Curtis.

[Steve Schlumpf]

Nice work Curtis! Congrats on a job well done! So..... does it work as well as you hoped?

[Brian McInturff]

Curtis,
I always admire those that like to make their own tools. 1 quick ? for you. Is there any vibration? I'm just wondering if you'll get any vibration since your tool holder is designed the way that it is.Not a lot of bulk for absorbing the torque put on the cutter since it isn't inserted inside the tool rod. Just curious before I attempt to build one ---- one of these days.
Thanks!!

[Jeff Nicol]

Curtis, All you had to do is drill the hole in the end of the rod and it would have done the same thing. You will have trouble with all that extra junk on the tip as the tool should be rear weight heavy to take away the leverage of deep hollowing. You also won't be able to cut straight in with the mass of the tool holder.

But to each his own and to the joy of youthful exuberance!

Good luck,

Jeff

[Ryan Baker]

So how do you like it?

Two comments come to mind. The first is that the extra chunk of metal holding the bit will probably get in your way all the time. Normally you want to narrow down the shaft near the cutter for better access. The second comment is that, IMO, your 3/8" cutters are really large. 3/16 is my favorite cutter size, and 1/4" in a 3/4" bar is starting to get on the large side. I find that the smaller cutter actually cuts faster and easier (and is much less grabby) than the bigger ones. But your mileage may vary, especially if you mostly work with softer, greener blanks. The easy thing is to drill a hole right in the end of the 5/8" rod and put a 3/16 or 1/4 cutter right in the end. You could always do that in the future if you change your mind.

Hope it works well for you. Hollowing tool preferences are a very individual thing.

[Dick Strauss]

The other quick and dirty method is to silver braze the HSS bit to the end of the rod. The silver material is actually stronger than the steel and can be applied using a standard propane torch.

[Bernie Weishapl]

My only comment is that with that piece on the end of your tool you will have to keep your tool rest back a ways from the piece so you can get it in and out of your HF. That means you won't be able to go as deep because you will have to much of your tool hanging over the tool rest which is going to cause you a lot of chatter. Also you will have to have a bigger opening. I also would have used a 3/16" cutter. So Curtis I hope it works for you and be safe.

[Leo Van Der Loo]

Good job Curtis, now you can hollow.
I think you will find that you don't want those sharp square corners on the tool, they can be grabby, especially going in and out of the opening, you also better get rid of that bearing race that's still on there.
As for the cutter being large, yes it is large, but you can try to take narrower cuts with it.
These are all lessons Curtis, next one or changing this one will come much easier with some experience under your belt already, good for you, have fun and take care

[curtis rosche]

i havent used it yet, i am going to try it out today on a peice of wet walnut. after i use it i will make ajustments to it, like grinding down the big end to make it smaller.

Jeff, i wouldve had to ordered smaller bits to put it right in the end. otherwise i would only have 1/8 on the sides and less than 1/16 on the corners, and that didnt sound to good to me

[Jeff Nicol]

Curtis, Just get rid of the big holder and drill the rod to fit a 1/4" hss cutter and you will be very happy! This is what I do and you can't beat it, sometimes bigger is not better. Go to my website: www.woodennicol.com and look at the video of my hollowing tool in action and you will see what I mean. We are all trying to save you some grief right from the start. You can put a 1/4" cutter in a 5/16" hole by knocking off the corners to make it fit the round hole, it is very easy to do. You can use your large cutters but get a little bigger rod and do the same thing, but I would side grind them to create more of a shear scraper finishing tool instead. So what Bernie, Ryan and I have said is what works. We did not get old for nothing!

Have fun and stay safe!

Jeff