DIY really tiny hollowing tools?

[Ethan Green]

Having spent a weekend with David Ellsworth, and seeing the very small hollow forms he’s done, I want to do the same. Toward that, I’ve purchased five HSS rods in 5/32 and 4” long. They should stay straight and hold an edge better than his screw drivers, Allen wrenches and nails, right? I’m envisioning these tools having 3” exposed, 1” embedded in the handles to hollow to around 2” deep. Has anyone out there done something similar? Specifically, I’m in need of some advice around shaping the tips and cutting edges.

I also may have access to some 9” long M42 HSS rods in 5/16” so I may do something similar with a few of them.

[Neil Strong]

Having spent a weekend with David Ellsworth, and seeing the very small hollow forms he’s done, I want to do the same. Toward that, I’ve purchased five HSS rods in 5/32 and 4” long. They should stay straight and hold an edge better than his screw drivers, Allen wrenches and nails, right? I’m envisioning these tools having 3” exposed, 1” embedded in the handles to hollow to around 2” deep. Has anyone out there done something similar? Specifically, I’m in need of some advice around shaping the tips and cutting edges.

I also may have access to some 9” long M42 HSS rods in 3/16” so I may do something similar with a few of them.

Grinding profiles into HSS is something most of us can manage.

Shaping HSS, in the sense of forging and subsequent heat treatment, is another level altogether from what is required for carbon steels. I understand that some traditonal Japanese woodturners can forge their turning (hook) tools from HSS, like M2, but forging HSS is not a workshop skill that many of us have accomplished in the West.

Ethan, if you are successful with forging and heat treating some HSS tools please come back and share your experience with us.

[Maurice Mcmurry]

All of my turning chisels were made from old files by my wife's Great Grand Pa. They are excellent, the best I have ever used. He was a machinist for the Boston And Maine Railroad. I have made several. Mine are just OK. Going very slowly at the grinder and keeping the water tray full took me too long to learn. My Tormek clone with running water has been an excellent addition to the rig. There is a thing called a Carbide-er. The transformer on ours has burned out. I look forward to getting it fixed. Once the carbide goes on diamond abrasives are required.

https://rocklinmanufacturing.com/rocklinizer/

[Edward Weber]

Hollowing 2" deep with a 3" tool is;
A) maxing it out, leaving little room to manipulate the tool.
B) putting a lot of stress on a 5/32 rod.
C) requires a good handle

Just because you're turning small objects, doesn't mean you need "small" tools. Only the cutting end needs to be of size for the job. A longer handle provides more control and a longer tool end allows for more maneuverability in the hollow form.
With the scenario you outlined, there is little room for your toolrest and hand before you're hitting the handle.
IMO 4" is very short

I may be at the other end of the spectrum but I hollow out ornaments with a 3/8" bowl gouge. Special tools may help but aren't strictly required. This has a 2 1/2" globe and weighs about 1.6 oz. (I usually try for 1.5 or under)
Bicrc & Koa.jpg

[Richard Coers]

What do you mean by a 5/32" rod staying straight? 5/32 can be a great chatter tool when it starts vibrating. We have to know the hardness of the comparison steel as well as the hardness of your rods to be able to judge which will hold an edge better.
I make my miniature tools from allen wrenches. They are already hard and have a bend. If you heat your steel rods to bend them, good chance they will be soft and you will have to heat treat them again.

[stephen thomas]

Specifically, I’m in need of some advice around shaping the tips and cutting edges.

What condition are the rods in? (Annealed, normalized, or hardened?)

Do you plan to forge them or machine from solid?

Can you link to images of tools you would be using as a reference shape and size?

I make loads of tooling in HC, HSS, Stellite tip, and some *brazed carbide tipped as well as insert bodies (cutterheads and stick tooling for inserts)
Almost all by metal reduction ("machining" &/or grinding from the solid)
I have done almost no HSS forging; though my kid brother does sometimes. For a useful edge tool, HSS will require a controllable HT furnace and some means of excluding atmosphere. It is not open forge or open torch work at the hardening stage for the edge. I use high temp foil pouches in a programmable furnace for the CPM M4 plane irons i sometimes make.



*Used to make & grind more brazed carbide tooling and even moonlighted professionally in another shop for a while.
But the health hazards are just too high. I'm glad i survived some careless episodes. It impinges on your local environment, too, if you do not have a shop with filtration and airlock doors - you will be tracking the residue, sight unseen, into the rest of your living space with loved ones and pets.

[Ethan Green]

Stephen, thanks for your helpful reply. I’m obviously not a metal worker. All I know of the current 5/32” rods is that they are HSS. My current plan is to grind a sloping flat on the top of one end and a curving grind below resulting in an angle of about 80 degrees to try it as a straight ‘boring bar’. If that seems to cut OK, I’ll make another with about a 1/2” or 5/8” leg at 45 degrees and maybe another at 90 degrees. I understand heating the rod to bend it will impact hardness so I’m hoping to not have to heat it to red all the way to the tip. I do have access to a heat-treating facility used by a major lathe tool manufacturer, and if my low-tech approach yields results I may do that. But first I want to see if I can make this work even a little.

[stephen thomas]

Cool!
You have to start somewhere with experimenting.
That will drive you to find predictable methods when you "almost" get exactly what you imagined.

The only thing i would add at this point is basic agreement with a previous poster's note that the shank length is not ideal.
If you really only intend to grip 1" of (round?) in a (wooden?) shank, it sounds iffy with the cranking forces in use.
I would make a metal handle (aluminum?) with the bore to fit the shank in the form of a compression fitting of some sort. Though worst case, a couple setscrews could retain it.
If you plan to do a lot of experimenting, there are all sorts of small ER and DA collet chucks with straight shanks that might be ideal, with a few collets in the range of shank size you intend to experiment with.
That could be keyed and epoxied into a larger wooden handle.

[Ethan Green]

Yeah, good point. At this point my main thing is determining a proper grind on rod that small. I have $8 into the rods so I’m not really concerned about achieving a high-quality end-use product. If the grind will cut, and if the grind will cut and keep cutting reasonably well after heating the rod to bend, I will get 8” rods in 5/32” and sneak up on a proper length and handling solution. I’ve already considered notching up the imbedded portion of rod with my CBN wheel to facilitate bonding with epoxy. I appreciate your input.

[Ethan Green]

The guy probably meant well, he just didn’t come across well. In a phone conversation recently David told me he knows nothing about metallurgy but has some small experience with tool making. I have his tools in 1/2” and in 3/8”; had a mild catch with the angled tip tool in 3/8” and bent the rod. That’s what I’m trying to move toward, hollowing tools with a little more stiffness and small enough to hollow through an opening around 5/16”.

[stephen thomas]

At this point my main thing is determining a proper grind on rod that small. I have $8 into the rods so I’m not really concerned about achieving a high-quality end-use product. If the grind will cut, and if the grind will cut and keep cutting reasonably well...

If you can already regrind, say, a gouge or even a contoured scraping chisel, i think you will do fine.
It is not rocket surgery. Clearance, and then making the grind so it is strong and doesn't occasionally snap off..... \After than, figuring out the geometry of relationships between tool cutting edge, shank, handle so it is not a constant fight/strenuous to use. Make a few and keep moving. It's the people who want to make a perfect (whatever) first try, and then give up when it does not work out that never get anywhere.

Are you aware of this type of "Weldon Countersink" tool, for chatterless deburring and countersinking in metal?


Does it suggest any possibilities for regrinding into a woodworking lathe tool?
(Not real familiar with what you want to do - I only do wood turning when i have to, and most of the time i do that in my planer or on the pin router. Like pool cues and table legs).

If you google, the Weldon CS's come in a range from tiny to quite large, and from cheap to expensive versions including carbide.
Again, i don't suggest carbide for homeshop grinding health reasons. But we all did it. At least wear a good respirator. Grinding wet (flood or heavy mist) keeps the dust down, but you should also be aware that wet, many of the heavy metal binders are absorbed through bare skin.

https://www.harborfreight.com/counte...4aAqFTEALw_wcB

https://www.google.com/search?q=weld...hrome&ie=UTF-8

This is an example of an ER16 straight shank collet chuck.
To fix into a larger wooden haft.

https://www.icarbide.com/cnc/16mm-x-...-collet-chuck/

If the largest tool shank you envision making is 7mm/1/4" or less, you could even step down to a smaller ER11 straight shank chuck.

[Ethan Green]

Oooh, those collets are interesting! I’ll look into them when I start getting close to a good result. I’m trying to make tools to make hollow vessels, only around 2” tall and hollowed through a very small hole.

[Neil Strong]

Cr-V of unknown HR-C, so not sure how good an edge they may take....

https://www.amazon.com.au/HORUSDY-8-...ef=sr_1_2_sspa

And, ready-made from Hosaluk and Martel...

https://woodturningtoolstore.com/pro...chael-hosaluk/

https://www.dictum.com/en/system-too...-size-1-729637

[Randy Heinemann]

If you ever decide to buy tools designed for mini-hollowing, Niclot Mini Hollers are sold on Trent Bosch's website. The tools are designed by Laurent Niclot who works with Trent. Laurent has been hollowing small pieces for quite awhile and does amazing things with them. I've seem him work with them and it's quite challenging to create the pieces he creates. The tools appear to be well-designed and from HSS. Just some additional resources.

[Michael Schneider]

For ideas, or something to copy. There are some small Hunter hollowing tools that you may look at. (there are also some very large ones). They are top quality if you want to drop some coin. https://huntertoolsystems.com/shop/