I have asked this question of Darrell Feltmate also and I am sure that I will get good info from him, but I thought I would see what other sources there are.
I want to make some of my own tools. I have found an easy source for the actual bits, but I am still looking for the tool shafts. Any help would be great.
Another question, I have not yet seen any of these athat are home made, but, I can't help but wonder at how the shaft stock is drilled for the bits. The bits are square stock and the shafts are round. Got any ideas of how to get a square hole in a round bar?Thanks
I'm sure you don't plan to make the shaft out of tool steel. I used a piece of round steel bought at Lowe's. I believe it is 3/4 diam. Had a friend with a metal lathe to drill a hole in the end that the bits would slip into. drilled and tapped two side holes for hex set screws to hold the bit in place. The shaft is about a foot long and the other end slips into a piece of pipe with two set screws to hold the shaft in place.
steel - look in the phone book under "industrial metal supply", visit a tool surplus yard, go to an automotive wrecking yard (rear axles make good tool shafts), etc.
drilling square hole - start round, use a broach - go to
You are correct, I don't really want tool steel but I wasn't sure what to call it. Now that I look back, it is "Cold Rolled Steel" that is used on the Oland toolds and on Darrell site.
Of course, now the question is, what the h*ll is cold rolled steel?
The shafts for the tools do not need to be tool steel if you are inserting a tool bit into them. I've use cold rolled steel from the hardware store for the shafts of tools. The tool bits you can purchase from many sources, MSC and Enco are two that I use.
Concerning your second question. Measure the square tool bit across the diagonals and drill a hole that the bit will just pass through. Then drill and tap a hole for a set screw that intercepts the hole at its center. Once the set screw is tightened, the square tool bit is held firmly in the round hole. I generally drilled two intersecting holes in the end of the shaft one on the center line of the shaft and one at 45 degrees. Where those two holes intersect is the place to drill your hole for the set screw. This enables you to use on shaft for straight cuts and also for expanded cuts when hollowing.
In a dim and distant past as a toolmaker I learned of a bewildering variety of steels. Each was suited to a more or less range of purposes. Some of the steels were suited to high impact work, others to a more sedate work. They could be classified as tool steels and then hot rolled or cold rolled. Cold rolled, as the name implies, is worked by the manufacturer to its dimensions while the steel was cold. Hot rolled, yeah, you guessed it, while the steel was hot. Hot rolled is a bit softer and bends easier than cold rolled. Cold rolled, to my experience, has a nicer finish. As to where you can get it, I get mine (cold rolled) at the local hardware store. Gerald's jamming the tool into a piece of pipe is also a good way of attaching the tool to the shaft.
"Fred Holder" wrote: (clip) I generally drilled two intersecting holes in the end of the shaft one on the center line of the shaft and one at 45 degrees.(clip) ^^^^^^^^^^^^^^^^^ You can also drill holes at both ends of the shaft, doubling the number of choices on diameter and angle.
People have discussed the difference between hot and col rolled mostly in terms of manufacture. In terms of use: cold rolled is smooth and shiny--hot rolled is dark and scaly. This could make a tiny difference in how the tool slides aross the tool rest. Hot rolled is cheaper. Cold rolled is a little stronger because the rolling work-hardens it. All these differences are trivial for your application. Buy whichever one you find first.
You can go to an industrial metal supply house and buy a short length of schedule 80 pipe. Schedule 80 pipe is typically used for steam lines. The pipe can be cut to whatever length handle you want.
There are pipe sizes available to hold 3/16", 1/4" and other standard tool bit sizes.
William, Did some Google homework. Still, I seem to have only found machine broaching and it seemed from your answer that this was something we could do in a home shop. Do you use a hammer/chiseling action or even a rotary hammer like SDS bit? Can't seem to find explanations for someone who's ignorant of the process entirely :)
Lots of good comments on this thread, so far. Broaching is a good idea for this application, but the broaches you probably saw require a through hole and need to be pushed through the round hole with something like an arbor press. Here's my suggestion: Go ahead and drill the hole in the end of the hot-or cold rolled mild steel bar..... But drill it about 1/64 or
1/32" smaller than the diagonal of the bit you are going to use. (I assume you are going to use square HSS tool bits, or carbide brazed onto square tool bits). Oil the hole. Take a brand new unsharpened tool bit with a squared-up end and drive it into the drilled hole a little way. Use vise grips to pull it out, pick out the shavings, then drive it a little deeper, etc.. You are broaching the hole. You don't need to totally square the hole, you are just broaching the edges to help hold the tool bit in place. You'd still use set screws. Maybe a bit of overkill, but this method positively locates the tool bit, since it would be hard to drill a hole that fits the bit perfectly. This way, any vibration created won't chew up the periphery of the round hole.
Pete Stanaitis
-----------------
Neillars> I have asked this question of Darrell Feltmate also and I am sure that
It's just plain low-to-medium carbon steel that has been formed cold. No need to worry too much about that, or even what it means, really- it's commonly availible at just about any hardware store. The ends should be color-coded, but it they're not, the cold-rolled bars should be smooth, while hot-rolled is a little rough, and usually still has some scale on it.
As far as the square hole goes, broaching is a fine idea, but it might be more than you care to invest in. (To be honest, I've only done it with a machine, and don't know if a guy can do it by hand or not.) I've got the same project on my to do list, and my plan is to drill a hole in the end of the bar whose diameter is the same as the width of the tool bits I've got for that project, and then heat the end of the bar in my forge and hammer a blank toolbit into the hole to make it square.
I'm going to go out on a limb here, and guess that you don't have a forge handy, but we're not talking about a major blacksmithing job here- there's a good chance that you'll be able to get it hot enough to do the job with a hand-held propane torch, or even a charcoal grill with a blower of some sort rigged up to get extra air into the coals. You'll want the bar to be cherry-red, and the tool bit to be room temperature.
If you do that, make sure to yank out the bit before the metal cools, or it'll get stuck. If it does get stuck, heat it up again and pull it out. Probably won't be easy to remove, but chances are it won't be the hardest thing you've ever done, either, and you'll have a nice square hole to show off- then you can just drill and tap a couple of holes from the side, and hold your bits in place with a couple of set screws.
Think of a hack saw or reciprocating saw blade. It's similar to that, only wider. You push it in, and it cuts and pulls out the shavings as you pull it out. I suspect hammering and chiseling would be very bad for the tool- most of the broaching I've seen is done at a fairly slow speed. The tool is very hard, and as metal gets harder, it tends to become more brittle and can't take impacts very well. The arbor press is a pretty good idea, but it's still probably more than you really need if you're just making one or two of these.
If you're willing to invest some extra time and elbow-grease, you could always file the corners out as well, though I can't think of too many people with the time or patience for that.
Wouldn't be a terrible idea to put a piece of unhardened steel between the bit and the hammer if you go this route, either. If the tool bit chips, those sharp little bits of metal can sting you pretty good- and they seem to have artery-sensing abilities. I managed to get the artery in my thumb once by hitting two hardened steel surfaces together, and while that wasn't all that serious, it could be a real problem if it strikes you elsewhere.
Neil.. I make my Oland tools out of bolts... mostly mild steel as it's easy to drill.
I pick a bolt of a comfortable length and cut off the head, then put it on the drill dress and drill the main hole... I think I was using a 5/16 bit... The 1/4" tool bit snugs up just fine in the round hole and the flats of the bit allow good locking with the set screw..
Also drill the set screw hole on the DP, size depending on set screw/tap size..
After drilling, I grind the end with the hole a little to give it some shape and thin the diameter a bit so it works better on the tool rest..
My last step is to turn a simple handle, drill a hole in it slightly smaller than the bolt and thread the bolt into the handle... I usually smear a little epoxy on the threads first, but it's probably not needed.. YMWV
Hi Prometheus Home shop square hole broaching is done quite easily. Drill a hole the same size or slightly larger (like 1/32") Grind the end of a same size tool bit square, and position and strike the bid with a brass hammer, knock the bid back out with a brass rod, and use a square file to remove the bur in the hole, don't try to drive the bit all the way through, just repeat the short amount of broaching, and filing the burr, if you use cutting oil it will help with the broaching, but clean the oil out before filing.
InspirePoint website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.