Home made parting tool

[Tiger]

Hey all,

I need a thin parting tool (ie as thin as possible without it flexing). I saw a nice one made up from a power hacksaw blade but as I don't have any of these blades around, was wondering what I could use instead to make the tool. Has anyone had any success with other materials eg knives? I have lots of old files but have heard too many stories about them snapping and actually saw it happen once so I don't want to use a file if I can help it.

[Hickory]

Great minds run in the same gutter.... I was just thinking of doing this task this afternoon.... :rolleyes:

I was picking up some junque in my garage, (to get to that mower, again) I picked up a long blade for a Saws-All, it is too dull to use for anything but it is tough enough to use for a narrow parting tool. I was planning on grinding off the teeth and shape a chisel point and attach a handle. I bet it has some good steel in it.

Got anything such as that?

[CameronPotter]

You can use files no problems - providing that you reheat treat them.

You could probably also simply get away with putting one in an oven for half an hour on the right temp to draw a straw colour to it (which makes it tougher, yet easier to blunten).

Cam

[davo453]

I used a power hacksaw blade to make mine, you can get them from basically any were that cuts metal. Got mine from Bohler Steel in Perth (was several years ago though). You have to ask nicely, smile sweetly and make sure their boss isn't looking.

Cheers

Dave

[soundman]

How about buying a piece of tool steel
the bigest problem is fixing the handle as its a bugger to drill.

power hack saw blades have been popular for all sorts of stuff for years.
just make sure you get a bimetal one & not a brittle "all hard"
& you will have to grind it up he right way.

cheers

[Tiger]

Thanks, guys for the responses so far.

Hickory, I do have some reciprocating saw (that's what we call saw-alls here) blades but they're still in working order so I can't use them yet.

Cam, I'm still reluctant to use files, someone at the local woodturning club is a constant reminder with a scar just above his eye.

[OGYT]

I saw one made from a paring knife. Just ground an edge on it, and use it for parting most items. The steel is okay, I guess. Think I'll try to make one like it...
OGYT
Wood is made for turnin'... not burnin'

[CameronPotter]

Fair enough Tiger. I wouldn't want you to hurt yourself, but most files are 1095 steel which is basically just high carbon steel. It is very good for knife making and chisel making.

However, if you are not confident with heat treating (and don't want to learn/give it a go) then being careful is a better solution. :cool:

Cam

[Tiger]

Cam, just to follow-up on your last point, what method do you use to identify steel, I am aware of the spark test but thought that only indicated whether it was high carbon etc?

[CameronPotter]

Yeah, that is about the only test that you can easily do in your backyard...

However, all Nicholson files are 1095 and many other files are the same. You could also look up the website of the file manufacturer (if it is stamped on the file who made it).

However, that is generally beside the point. The point is that files snap because they are brittle. The way that ALL tool steel (so far as I am aware) is hardened and annealed follows the same basic process:

1. Harden the steel as much as possible. At this stage the tool will be very good at holding an edge, but brittle.

2. Temper the steel. This reduces the edge holding capability, but also makes it less brittle. All knives are a balance between edge holding and toughness (until you get into differential hardening).

Now, files are meant to stay sharp as long as possible, but they aren't designed to be subjected to striking forces or even bending forces, so they are pretty much left in the fully hardened state, chisels and knives need to be more robust, but can be resharpened so the edge holding aspect is less important - thus they are tempered.

Therefore, if you temper your file, it will be similar to knife or saw steel that you would use anyway...

The trick (and disclaimer) is that it has to be done right - but this isn't all that hard... and if you temper it too much, you will simply have a tool that needs constant resharpening.

Cam

ps Wayne Goddard once did the bend test with an otherwise unaltered file. He tempered it and bent it by 90 degree without it breaking, before letting it go and it went back to approximately straight. This is a VERY tough test of a knife though, but one you need to be able to achieve to become a master bladesmith with the knife makers society.

[Tiger]

Thanks, Cam, where did you do your metallurgy degree?:)

[CameronPotter]

On the internet... :p

If you are interested in this stuff, I would recommend the $50 knife shop, simple and fun to read but HEAPS of good info. Also, there is an email list called Knife List that is good - oh and bladeforum.com and swordforum.com

I have also read several other books on knifemaking and a book on heat treating - but only the parts that I could approximately emulate in my backyard.

Cam

[Wood Butcher]

You can use files no problems - providing that you reheat treat them.

You could probably also simply get away with putting one in an oven for half an hour on the right temp to draw a straw colour to it (which makes it tougher, yet easier to blunten).

Cam

Cam, putting a file in the oven at home won't do squat. For High carbon steel you need to get the steel to over 700deg C to do anything to the crystalline structure

[Baz]

I know this is about home made thin parting tools but quality thin parting tools are available. Carba Tec cattledog page 178 Hamlet M2-089, the photo shows it as an M2-069.
Cheers
Barry

[CameronPotter]

Actually Wood Butcher I will have to disagree with you on that. Be careful making statements that you cannot support.

Plenty of professional knife makers use home ovens to perform precise tempering on their knives, so unless you are a professional knife maker (or metallurgist) I will ask what your source is... I can list dozens - probably hundreds - of reliable sources to back me up.

Try even doing a Google search... first site that I got said:


Tempering is done immediately after quench hardening. When the steel cools to about 40 ºC (104 ºF) after quenching, it is ready to be tempered. The part is reheated to a temperature of 150 to 400 ºC (302 to 752 ºF). In this region a softer and tougher structure Troostite is formed.

Be careful about whether you are quoting degrees C or Farenheit.

Also, another reason I can state conclusively that it works - I have done it. :p

Now, it does depend on the steel, but as I said, most files are a pretty basic carbon steel.

Cam

[CameronPotter]

Oh, also, while I am being pedantic - Bob Engnath, possibly one of the most respected knife makers ever, created a site with A LOT of information on it. I suggest you read there to get more information on this:

http://www.engnath.com/public/manframe.htm

Go to Heattreat from the choices on the left...

Go to a section sawing, "Oven Drawing Colours".

Read the information, then copy this and put it somewhere you will remember it:



The colors are a very precise indicator of temperature with simple carbon steel.
400 degrees, pale straw
425 degrees, straw
490 degrees, golden yellow
500 degrees, brown
525 degrees, brown purple
570 degrees, purple
600 degrees, bright blue
650 degrees, pale blue


NOTE: the temperatures are in Farenheit. The average knife is best tempered at about straw yellow. A turning chisel might be slightly safer at about brown, or even brown purple. Once you get to pale blue, you have steel that won't even hold on edge...

So much for doing "squat" eh? It seems you got me riled up... ;)

[Wood Butcher]

I spoke to the Metalurgy Professor at uni as my source. You mentioned a straw colour. My engineering texts refers to a colour over 900degC. and the quote "softer and tougher" is a complete contradiction to everything that I have been studying in metallurgy for the last 6 months. Softness (or correctly ductility) is proportional to true "toughness".

I can see what you are saying but the terminology is wrong from an engineering point of view. I think what you refer to as tougher is different from the true engineering definition of toughness, this is why I got confused. I will admit I don't have the skill to be able define this but I can give references to several highly regarded texts if wanted.

[Grunt]

Home made parting tool

A comb?

[RETIRED]

http://www.anvilfire.com/FAQs/heat_faq_index.htm

[CameronPotter]

I spoke to the Metalurgy Professor at uni as my source. You mentioned a straw colour. My engineering texts refers to a colour over 900degC. and the quote "softer and tougher" is a complete contradiction to everything that I have been studying in metallurgy for the last 6 months. Softness (or correctly ductility) is proportional to true "toughness".

I can see what you are saying but the terminology is wrong from an engineering point of view. I think what you refer to as tougher is different from the true engineering definition of toughness, this is why I got confused. I will admit I don't have the skill to be able define this but I can give references to several highly regarded texts if wanted.

Fair enough.

I also thought about this last night.

I assume that you were talking about adjusting the actual bonds (in which case you have to take it up to the transition phase area (around 900 deg. C), but to stop a tool being brittle you actually just have to "relax" the metal.

Tempering basically jiggles the metal lattic so that it is slightly less stressed. If you take a file and break it in two then look at the grain - the break will be lumpy as the grain is large. Then if you take the same file and put it in an oven at 250 deg C for half an hour and try to break it - one, it will be almost impossible to snap; two, if you can snap it, the grain at that broken area will be much smaller.

Cam

[JackoH]

I'm with Baz. Go out and buy one!
Save all the complications, and dangers of tempering. Particularly if you don't know what you are doing.
Jim Carroll can probably supply.

[Tiger]

I have found an old tenon saw with most of the teeth gone so I may try and cut that and make this parting tool. Only thing is I can't get the blade out of the saw. There are rivets and I have drilled through one of them, but the blade won't budge. The metal spline (although I can bend it) still won't release the blade. How do you get the blade out????:confused:

[echnidna]

You can part off in a woodlath with an ordinary hacksaw just tension the blade up tight.

[CameronPotter]

I have found an old tenon saw with most of the teeth gone so I may try and cut that and make this parting tool. Only thing is I can't get the blade out of the saw. There are rivets and I have drilled through one of them, but the blade won't budge. The metal spline (although I can bend it) still won't release the blade. How do you get the blade out????:confused:

Cut it off with a grinder?

Anyway, if you can afford, a bought parting tool would be an easy alternative that will work better (as it will be HSS).

Cam

[Gil Jones]

Look in the 'General Information' section at his site.
http://www.crucibleservice.com/eselector/index.html

Plenty of other interesting reading at this site too.

[Tiger]

Cut it off with a grinder?


Cam

Cam, I had thought about using a grinder but there must be a way of releasing the blade easily:confused: .

[Gil Jones]

Not if it is induction, or spot welded.

[RETIRED]

I have used a "Stanley" knife as a parting tool on the odd occasion.

[Tiger]

I have used a "Stanley" knife as a parting tool on the odd occasion.

Good idea, how safe is though?

[rsser]

Electric planer blade?

Or see the thin tool at http://www.cws.au.com/cgi/index.cgi/shopfront/view_product_details?category_id=1107144951&product_id=1107369977

Not a lot of money.