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Scriber

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Wolfie13/10/2011 20:09:10
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What material do I use to make a scribing point and how do I grind it so that the point is central. And do I need to harden it.
 
Thanks
JasonB13/10/2011 20:16:07
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You could make it from silver steel, the point can be turned in the lathe so would be concentric with the OD.
 
It will need hardening and tempering to dark straw-brown
 
J
wheeltapper13/10/2011 20:32:51
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A quick way to make a concentric point is to hold the rod in a power drill, spin it up to speed and hold the rod against a grinding wheel.
 
arrange the position so the wheel and rod are going in opposite directions and you will have a nice centered point, it can't do anything but be central.
 
Roy
 

Stub Mandrel13/10/2011 21:34:47
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Nice tip Roy!
 
Neil
Wolfie13/10/2011 23:49:21
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That'll do, good tip cheers.
Ian S C14/10/2011 04:31:02
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If you'r somewere were they are common, old chainsaw files do the job. Some where about 5 mm or 6 mm would be fine, even if you had to buy new, they are that cheap, you can't go wrong. Use Roy's sharpening method, good for center punches too.
I also use the chainsaw files for little center punches, I reheat treat the punches. Ian S C
Wolfie14/10/2011 06:36:25
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Thats handy to know. Living in rural North Yorkshire, chainsaws aren't uncommon, I own one myself for firewood logging. And even better I have a 4mm file I've just replaced!
 
What do you mean by reheat treat?
Tel14/10/2011 08:36:52
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"What do you mean by reheat treat?"

Chainsaw, or any other, files are too hard for a lot of uses, especially punches which will shatter, you need to let the hardness back by heating up until there is colour running up the steel and quench it when you reach the desired colour, which will correspond with a specific hardness. Google should turn up plenty of charts to show what is needed.
Tel14/10/2011 08:39:40
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BTW, old gramophone needles (if you can find any) made dandy fine scriber points. Resharpened concrete nails are OK as well.
methusala14/10/2011 09:25:54
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Hi Wolvie,
Another type of scriber you can make for scribing around the profile of a
component is to make the scriber as described above, then file a flat about 3/8 to 1/2
long from the point, and to the centre of the point .This will ensure that the point of the scriber is close to the edge of the job you are scribing around. hope the above makes
sense to you.
Colin.
 

 

colin hawes14/10/2011 17:41:42
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My scribers are made of 6ins of 1/8 silver steel,ofhand sharpened,1in bent to 30 deg. and hardened at both ends. I have never found a need for a truly central point.
tractionengine4214/10/2011 18:01:31
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I have been using a 0.1mm dia x 10 deg carbide engraving cutter, it has half it's dia ground away like a 'D' bit making the point 0.05mm. I have found it provides a good line for locating a center punch and hard wearing, thay are very cheap on ebay, just bought some 5 for 5 pound + 3 pound p&p. They are advertised as PCB engraving cutters
 
Just to clarify, I am not engraving the line, I am using the engraving cutter as a scriber, The cutter is 1/8" dia, I drilled the end of a 3/8" bar and loctited it in.
Nigel

Edited By tractionengine42 on 14/10/2011 18:06:20

JasonB14/10/2011 18:35:18
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Posted by colin hawes on 14/10/2011 17:41:42:
My scribers are made of 6ins of 1/8 silver steel,ofhand sharpened,1in bent to 30 deg. and hardened at both ends. I have never found a need for a truly central point.
 
Wolfie wants it central as this post was prompted by the link I posted in the thread about scribing a circle and that tool needs a concentric point.
 
J
Gordon W14/10/2011 20:13:52
2011 forum posts
When I was an apprentice we made scribers from old hacksaw blades ( 1"" industrial) also allows close up work. Nowadays I make them from masonery nails in a wooden handle, made 3 lastweek and can only find one now. BTW don't carry the hacksaw ones around ,the police take a dim view.
Stub Mandrel16/10/2011 20:38:36
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Put a new point on my carbide scrbe today using Roy's tip. Used a mini drill and the green grit wheel on my grinder. Much more central point than the previous hand-ground one which was annoying me.
 
Neil
Wolfie19/10/2011 21:27:54
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So can I make a scriber out of stainless or mild steel and simply heat it up and quench it?
Thor20/10/2011 06:01:48
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Hi Wolfie,
 
I don't think mild steel has a high enough carbon content to be hardened by heating and quenching. JasonB suggests silver steel which has a much higher carbon content and can be hardened by heating and quenching, then tempered.
 
Thor
Nicholas Farr20/10/2011 06:48:39
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Hi Wolfie, basically no. Mild steel will not harden when quenched, but will case harden using a compound containing carbon. Most stainless steels will not harden when quenched either, you would need a martensitic stainless steel, and unless you happen to have some for nothing, it would be cheaper to buy a commercially made scriber. As has been said, Silver steel will be more suitable, or some of the other options mentioned.
 
Regards Nick.
ady20/10/2011 06:51:17
612 forum posts
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The cheapo engraver I have does all metals and even marks glass.
 
The tip is a pointy one and is made of tungsten steel.

Edited By ady on 20/10/2011 06:52:00

Terryd20/10/2011 07:37:23
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HI Wolfie,
 
Hardening and tempering of steels is a vital part of engineering and you really need to master the process as much as any other, here are a few tips I hope may help. Only medium and (preferably) high carbon content steels will harden, most stainless steels will not harden. You can 'case harden' mild (low carbon) steels but that is another kettle of fish entirely.
 
Hardening and tempering is a two stage process. First you harden (Durr!) by heating to cherry red and holding there for a few minutes (soaking) to allow the changes in the steel to take place. It is then quenched in oil or water depending on the steel type to 'freeze' the new properties in the steel. However it is then too hard and brittle for most purposes.
 
It must be 'tempered' to draw out some of the hardness and impart a toughness depending on the purpose. If a tool is to be hit ( cold chisel, punch etc) it needs more toughness (higher quenching temp) if it is to cut it needs more hardness (e.g. scriber, file). These temperatures are quite critical but easy to spot on a hardened steel which is polished before heating for tempering, They range from pale yellow (coolest - less temper) e.g. turning tools, and pale blue (hottest - more temper) e.g. springs.
 
There is plenty on the web about this but here is a page, and a video to get you started. There is also a good book in the Workshop range available here.
 
Best regards
 
Terry

Edited By Terryd on 20/10/2011 07:47:26

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