Brazing Drill Rod onto Tool Rest

[RichColvin]

I have a PM 3520B with the factory-supplied toolrest. Was thinking of brazing drill rod to the top. Does anyone have experience with this ?

Rich

 

[John Torchick]

Off topic, used to live in Shadeville and Grove City in the 50s and 60s.

 

[robo hippy]

It seems to be more labor intensive than the welding, but the welding is tricky. There are issues with welding hardened drill rod and losing the hardening. You do need to harden the drill rod first. Epoxy is the simple way to do it, but if you drop the tool rest, it can pop off, and you can epoxy it back on. Lock Tite, and JB weld both work.

robo hippy

 

[Raul McCai]

If the Drill Rod is HSS you won't have to worry about de-tempering no matter the welding technique you use
HSS can be MIG TIG and Arc welded just fine
Silver solder and even lead solder work great

But you have another consideration - - the base metal is cast iron

About cast iron
Cast iron is a funny thing. Low temperature attachment like silver solder is probably the best option because of a goofy quality cast iron has.

When you arc or TIG or MIG weld the stuff, it tends to experience substantial expansion in the area of high heating. Then when it cools, it cools very fast and there develops a shrink induced crack line that can destroy your part. IT can just crack into pieces right on the bench minutes after welding.
Welders address this with high nickel content rod and a lot of preheating of the whole part to be welded and then a slow controlled ramping back down to normal room temperature. They heat the whole part to about 900F then ramp it down slowly after welding.

 

[john lucas]

I have a Robust tool rest and the rod is epoxied to it. I have had my rests that came with the Powermatic for close to 14 years now. They do have minor dings in them but I file them down periodically and they don't cause a problem. Ideally you would need to mill a slot for the rod so that you have enough surface area to really hold the rod.

 

[RichColvin]

Raul,

The existing rest's metal composition was what concerns me. If it is cast, I'll probably follow John's recommendation & just keep on filing it when it's out of whack.

Rich

 

[Bill Boehme]

?.. About cast iron
Cast iron is a funny thing. Low temperature attachment like silver solder is probably the best option because of a goofy quality cast iron has.

When you arc or TIG or MIG weld the stuff, it tends to experience substantial expansion in the area of high heating. Then when it cools, it cools very fast and there develops a shrink induced crack line that can destroy your part. IT can just crack into pieces right on the bench minutes after welding.
Welders address this with high nickel content rod and a lot of preheating of the whole part to be welded and then a slow controlled ramping back down to normal room temperature. They heat the whole part to about 900F then ramp it down slowly after welding.

I was about to mention the hazards of welding cast iron, but you did a much better job of it than I would have been able to do. And, the Powermatic tool rest is cast iron, Rich.

Personally, I would leave the Powermatic tool rest as it is and buy a Robust rest or a rest from Steve Sinner (Advanced Lathe Tools). I need to check my Robust rests to see if there are any welds. Epoxy should be fine because many turners do that. The rod on my ALT rest is tack welded in several spots.

 

[hockenbery]

I tend to agree with Bill why sacrifice a perfectly good tool rest.

I use my old oneway rest a lot
I also have a couple of Robust rests that are terrific.
The 4" comfort rest and the big j rest, and I got a littleJ rest for the jet 1221.
I plan to get one of the low profile rests.

Depending on what i an doing I may want to reach under the rest to support the work.
The oneway rest is great for this.
The comfort test is near perfect for turning spheres.
The j rest is the best thing I have found for hollowing bowls.
The short left end never seems to hit anything like a tool handle or my body if I lean in.

 

[Mike Johnson]

If you take the time to modify an existing tool rest, it might be just as easy to fabricate
a new tool rest. You can easily order several pre-cut pieces of round steel any grade desired
and weld, braze, bolt, machine, the pieces together.

 

[Richard Coers]

Oneway uses ductile iron castings, not sure what Powermatic uses. Ductile has a higher graphite content than common cast iron, so even tougher to braze or weld.

 

[robo hippy]

Well, why change a perfectly good tool rest??? After using the hardened drill rod tool rests, I will never use cast iron again.To me the difference is as big as the difference between standard and CBN grinding wheels. Mostly it is greatly reduced friction as you slide your tools across the tool rests. I have the Oneway curved stainless tool rests, and they are a step up from the cast iron, but still not as good as the drill rod.

Raul, HSS drill Rod??? Never heard of it. Do you know if it gets as hard as the other forms of drill rod?

robo hippy

 

[Raul McCai]

Raul, HSS drill Rod??? Never heard of it. Do you know if it gets as hard as the other forms of drill rod?

https://www.mscdirect.com/browse/tn...M2-High-Speed-Steel-Drill-Rods?navid=12102230

High speed Steel whether M2 or conventional HSS has exceptional cherry red hardness. One must heat it beyond cherry red to take the temper out of it. One can use any weld braise or soldering pocess to fasten it to a substrate without fear of ruining the temper of the non welded parts

 

[Don Bunce]

I didn't see anything that said the M2 HSS comes in a hardened state... Drill rod is normally supplied soft, and requires hardening. You can get drill blanks that are pre hardened, but usually are only about 4 -6 inches long. From the prices I've seen, if it was available in longer lengths, it would be cheaper to just buy a Robust rest and be done with it.

Has anyone used music wire(piano wire) for this purpose? It is available at hobby stores in 36" lengths for just a few dollars . You can file it, but it will take the teeth off a hacksaw. I looked it up on the internet, it is listed at about a Rockwell hardness of 45-60.

 

[Clifton C]

MSC's drill rod is not sold "heat treated" and the heat treating of M2 HSS is not something I can do. I've JB welded O1 as I buy it from (old) ENCO to shop made tool rests and sure like the feel, over cast iron, when using HSS turning tools. One of the questions I have is, can the tool rest be too hard? I suppose HSS on HSS is ok, but if my boring bar is cold rolled steel I would rather have that on a cast iron tool rest not M2. Thoughts?

 

[Bill Boehme]

Reed, high speeds steel is one category of a broader classification called Tool Steel. The other types of tool steels have a high carbon content compared to mild steel. And, yes high carbon tool steel such as O-1 and W-1 can be hardened to approximately the same hardness as as M-2 HSS. The advantages of HSS include maintaining its properties at much higher temperatures (hence high speed) and having both higher hardness and toughness at the same time compared to high carbon tool steel. Toughness, basically is the ability to withstand high energy impacts without fracturing. For a cutting tool its toughness would tell you the resistance to chipping of the cutting edge. Hardness for a cutting tool tells you the ability of the cutting edge to hold up to abrasion. Increasing hardness reduces toughness and vice versa. There is no absolute right answer about the right hardness because it's always a trade off between conflicting requirements.

I don't know what kind of round bar stock would work best. High carbon drill rod is sold annealed, but that is still much harder and tougher than a cast iron tool rest which gets nicked so easily. We wouldn't want it to be so hard that it is liable to fracture from an impact. I have no idea how M-2 HSS is supplied. We wouldn't be able to heat it to a high enough temperature to heat treat it. Since I've used O-1 drill rod to make a few tools, I have a gut feeling that it would work just fine in its annealed state on a tool rest.

Off topic a bit, but do you remember the discussions years ago about cast iron vs steel tool rests? There were some doomsday predictions that steel toolrests would be the ruination of woodturning as we know it. I'm still waiting to see if that prediction comes true.

 

[Raul McCai]

Hutchenson and Griggs will sell it hardened for you if that's what you want.
http://hssblanks.com/hssblanks/index.htm
https://www.griggssteel.com/HardenedBars.php

Doug Thompson also has hardened blank rods


It's hard to imagine people heat treating HSS in small shops. We ran a heat treat facility in a tool room that I worked in. But reducing atmosphere and salt baths were not part of our capability.

the material is so tough and dense that I rather suspect that it's plenty tough just as it is in the annealed state.

 

[john lucas]

It's a lot of work to properly modify a traditional tool rest. It's much simpler to just buy a good one from Bestwoodtools, or Robust. I have some of each and really like them although I still use my 2 Powermatic cast tool rests quite a bit because I don't have those sizes in the others. I wax my tool rests with a candle and they all slide slick as butter so I don't really see much advantage to the hardened steel ones.

 

[hockenbery]

A filed and waxed oneway rest or powermatic rest works just as well for me a freshly sanded Robust rest.
I love my Robust rests but they get sap on them that makes them drag. 220 sand paper makes them glide smoothly. I hardly ever touch the 4" Robust since it rarely gets hit with wet wood.
The j rest does a lot of wet wood and gets attention when needed.

I carry a file and candle in my demo box.
There are a lot of sad rests out there.

 

[Odie]

Off topic a bit, but do you remember the discussions years ago about cast iron vs steel tool rests? There were some doomsday predictions that steel toolrests would be the ruination of woodturning as we know it. I'm still waiting to see if that prediction comes true.

I haven't heard the discussion about how steel tool rests are bad for woodturners, Bill. What was the reasoning for that?

Note: I have a couple of cast iron tool rests, but don't use them anymore......tools don't slide on them as well as harder rests do. Now, all of my tool rests are steel, or Robust rests. My Oneway rests see quite a bit of use. The harder rests seem to be better for the tools to slide. Occasionally, I use a 3M deburring wheel to clean them up, and polish the top surface.

ko

 

[Bill Boehme]

A filed and waxed oneway rest or powermatic rest works just as well for me a freshly sanded Robust rest.

You sand your Robust rest? Oh, the humanity, oh the tragedy!

I use Johnson, paste wax and that makes it slicker than anything else that I have tried. It also seems to make stuff less likely to stick to it.

Actually, I have sanded my Robust rests, but I use silicon carbide paper and go all the way up to about 1500 grit and then I use automotive metal polish to make it shine like chrome. I think that is a big improvement over the way that they come from the factory (smooth, but not slick). I also do the same thing to my gouges. With both surfaces polished so smooth I can hardly keep the gouge from just skating off the rest (I'm just kidding about that last part, but it is smooth).

 

[robo hippy]

Hmm... More food for thought... There seems to be 3 types of drill rod, O for oil, W for water, and A for air, which as near as I can tell is a curing method for the different rods. The A is supposed to keep getting harder with more exposure to air, and is the hardest of the group before being hardened. There is another variation called A2 which is better at keeping its hardness if after hardening, you heat it to about 350, and weld when hot. I am wondering if the M2 HSS will be as hard when it is hardened or tempered. With the drill rod, you can't ding, dent or scratch it, and I have tried... There must be some flex to it because it doesn't shatter if you drop it. I have no idea about piano wire. The drill rod I am trying to use is 5/16 inch. Just about every town of any size will have a black smith who could probably do a fair job of hardening drill rod. I used Lock Tite epoxy to stick some of the A type on some prototype inside bowl rests, and it isn't quite as slick as the hardened drill rod. Larger cities will have some place that specializes in hardening, and it is done by the pound.

As far as crud on the tool rest, I don't remember ever having problems with the drill rod getting sticky, and that is even with madrone which leaves a crust on me when I turn a bunch of it. Just in case, I have one grinder with a dedicated wire wheel on it for cleaning gunked up tools. I do stand out of the line of fire when using it as the wires come out... I have found them sticking out of my turning smock...

When testing some drill rod, A, O, W, and one unknown sample that was hardened, and one Robust rest, I tried hack saw blade and 220 red aluminum oxide abrasive to see if they would mark the steel. The robust was the only one that didn't mark at all. The one hardened one barely had any marks, and the others would all cut with the hack saw blade, and the A was by far the hardest untreated.

robo hippy

 

[Bill Boehme]

I haven't heard the discussion about how steel tool rests are bad for woodturners, Bill. What was the reasoning for that?

Note: I have a couple of cast iron tool rests, but don't use them anymore......tools don't slide on them as well as harder rests do. Now, all of my tool rests are steel, or Robust rests. My Oneway rests see quite a bit of use. The harder rests seem to be better for the tools to slide. Occasionally, I use a 3M deburring wheel to clean them up, and polish the top surface.

ko

I think that it was about as valid as the cast iron vs. steel lathe arguments. I don't remember much about it, but I think that there was the concern that the steel rest would vibrate and maybe was too slick ... maybe one of the cardinal rituals in woodturning was dressing the tool rest.

 

[robo hippy]

The only rest I have that vibrated was the Oneway inside bowl rest. Go all the way out to the end and it would bounce for all but the very lightest cuts. The Robust is solid all the way out to the tip because it has a support finger under it like the Oneway bowl coring system does.

robo hippy

 

[john lucas]

The Bestwoodtools tool rests are made from a low vibrations steel that was destined for NASA spacecraft. At least that's what Vic told me.

 

[Bill Boehme]

The Bestwoodtools tool rests are made from a low vibrations steel that was destined for NASA spacecraft. At least that's what Vic told me.

That sounds like a story alright. What amuses me is that every time I see any woodturning related product advertised that uses 6061 aluminum, it's always preceded by the words "aircraft grade" (usually in quotes). There are a number of aluminum alloys used in aircraft and if any aluminum alloy could be called "aircraft grade" the honor would have to go to 7075 T-6 aluminum. The most commonly available general purpose alloy is 6061 T-6 because it is strong, corrosion resistant, and easy to weld. It is commonly found in extrusions and sheets.

 

[Hy Tran]

Hmm... More food for thought... There seems to be 3 types of drill rod, O for oil, W for water, and A for air, which as near as I can tell is a curing method for the different rods. The A is supposed to keep getting harder with more exposure to air, and is the hardest of the group before being hardened. There is another variation called A2 which is better at keeping its hardness if after hardening, you heat it to about 350, and weld when hot. I am wondering if the M2 HSS will be as hard when it is hardened or tempered. With the drill rod, you can't ding, dent or scratch it, and I have tried... There must be some flex to it because it doesn't shatter if you drop it. I have no idea about piano wire. The drill rod I am trying to use is 5/16 inch. Just about every town of any size will have a black smith who could probably do a fair job of hardening drill rod. I used Lock Tite epoxy to stick some of the A type on some prototype inside bowl rests, and it isn't quite as slick as the hardened drill rod. Larger cities will have some place that specializes in hardening, and it is done by the pound.

As far as crud on the tool rest, I don't remember ever having problems with the drill rod getting sticky, and that is even with madrone which leaves a crust on me when I turn a bunch of it. Just in case, I have one grinder with a dedicated wire wheel on it for cleaning gunked up tools. I do stand out of the line of fire when using it as the wires come out... I have found them sticking out of my turning smock...

When testing some drill rod, A, O, W, and one unknown sample that was hardened, and one Robust rest, I tried hack saw blade and 220 red aluminum oxide abrasive to see if they would mark the steel. The robust was the only one that didn't mark at all. The one hardened one barely had any marks, and the others would all cut with the hack saw blade, and the A was by far the hardest untreated.

robo hippy

Steels get all sorts of different names. Heating a (tool) steel up to high temperature causes the crystal structure to change (I won't define the high temperature or the crystal structure, just take my word for it). If you then quench (in other words, chill quickly), you "freeze-in" the crystal structure. This makes the steel "hard" (resistant to dings, etc.); it also makes it brittle (think Titanic; iceberg). You then re-heat the steel to a lower high temperature for some amount of time. This reduces the hardness a bit, but also improves the toughness (ability to ding without breaking). This is called tempering.

An "A" tool steel is quenched in air (typically). A "W" tool steel is quenched in water. An "O" tool steel is quenched in oil. All these names are AISI names (American Iron & Steel Inst.).

Quenching in water or oil gives the fastest cooling; quenching in air gives the slowest cooling.

Some steels require hybrid quenching; M2 is one of these (oil quenched to ~ 1000 F, then, air quench after). The "M" letter indicates that the major alloying element is Molybdenum. 10V (what Thompson uses) is 10% vanadium. It also has a different name, A11, which indicates that it is air-quenched.

For drill rod, regardless of the quenching method, the entire rod is hardened. For larger diameter materials (say greater than 10 mm diameter), the outer portions are harder than the inner portions, because the outer portions cool faster (and freeze in the crystal structure better).

If you want to spend the $, you can buy a set of files with different hardnesses (use your favorite search engine, and use "hardness testing files" as the keywords). I would not buy from ebay; I would buy from an industrial distributor, such as Flexbar, MSC, McMasterCarr, etc. and use to test your drill rods, to see if the heat treater treated correctly. This is likely to be much more quantitative than the hacksaw test.

I'm neither a materials scientist nor a physicist; but I occasionally pretend to be one

 

[Richard Coers]

This makes the steel "hard" (resistant to dings, etc.); it also makes it brittle (think Titanic; iceberg)

The Titanic was made from tool steel? Wow!
I've read recently that they had a coal bunker fire from the day it left Europe. They were steaming at high speed to empty the bunker faster. Other ships had stopped in the ice berg field at night, but the Titanic had to get through the coal to get to the fire so kept speed up. To me, that starts to indicate operator error as much as a steel issue.

 

[Hy Tran]

This makes the steel "hard" (resistant to dings, etc.); it also makes it brittle (think Titanic; iceberg)

The Titanic was made from tool steel? Wow!
...

Woops, sorry--I was trying to make an analogy to say that temperature affects the behavior of materials dramatically. The steel used back then became brittle at low temperatures. Perhaps I should have said "chewing gum, freezer" as an analogy?

Operator error:

Accidents in general--generally a cascade of events. Hence, we use multiple steps to protect ourselves in the wood shop. We don't just put on safety glasses and headshield and call ourselves safe. We think about set up, workholding, not standing in the line of fire; we think about the soundness of the wood we use, etc.