Hand Plane Iron Chipping

[marku]

Hi, this is my first post although I have been reading other peoples with interest for a while now.

Recently I decided that it was time to try out doing a bit more with hand tools and less power tools.

I bought a Record No 3 plane from Ebay and I think it dates from the late 1950's

I have sharpened it by hand and every time I use it the iron chips within minutes of using it.

I have sharpened it to 25 degrees as per the guide on the plane, is the angle the problem or has the iron been damaged at some stage by getting to hot.

Any help would be great Thanks, Mark

 

[Joe]

Hi Mark,

A few questions: have you honed a secondary, steeper bevel on the blade or are you using it at 25 degrees? What are you planing? I assume, given the age of the plane, that the blade has been sharpened many times, as evidenced by its length?

Joel

 

[yetloh]

Welcome to the forum Mark.

I always sharpen them at 30 deg. Give that a try, but it may just be a duff blade, in which case you would be better ditching it and buying a quality blade. It might cost you as much as the plane but good quality edge tools are always worth it in the end.

Let us know how you get on.

Jim

 

[marku]

I have only ground a 25 degree bevel on the iron I will try grinding a secondary bevel on it in the morning and see how that goes.

It has only been used on some soft wood and it chips almost immediately.

Thanks for the help I will report back tomorrow.

 

[Harbo]

Mark - if the iron proves to be completely duff - Ray Iles sells replacements that fit Stanleys etc.

http://www.oldtools.co.uk/new.tools/ray.iles/ray.iles.pg1.php


Rod

 

[marku]

Thanks for the info on the replacement iron, it may prove to be the way forward. The rest of the plane is excellent it even has the original box instructions etc.

I will try grinding a couple of different bevels and see what happens, Thanks Mark

 

[matthewwh]

Hi Mark,

Typically the iron is ground at 25 then honed on a coarse/medium stone at 30, producing a smaller 'secondary bevel' that can then be polished on a finer stone. The steeper secondary bevel gives you a smaller area to polish and also strengthens the edge.

It's unlikely to be that the blade has been overheated as this usually tends to make the edge softer and is easily ground back. To make it harder someone would have to have got it hot enough to glow and then quenched it.

If it is failing by chipping rather than rolling over then it will be harder than the optimum, however if it will keep an edge with a secondary it may well turn out to be a very nice blade.

 

[AndyT]

The Record blades did have an indication of a 25 degree grinding angle on them, but the advice always was to then hone a 30 degree cutting angle on the tip.
That would be done by hand (so as not to upset the temper of the steel) using whichever method you prefer (oilstone, waterstone, diamond hone, ceramic stone, abrasive sheets aka Scary Sharp etc).

Just a 25 degree angle on its own would be too fragile at the edge - as you have proved!

 

[bugbear]

The Record blades did have an indication of a 25 degree grinding angle on them, but the advice always was to then hone a 30 degree cutting angle on the tip.
That would be done by hand (so as not to upset the temper of the steel) using whichever method you prefer (oilstone, waterstone, diamond hone, ceramic stone, abrasive sheets aka Scary Sharp etc).

Just a 25 degree angle on its own would be too fragile at the edge - as you have proved!

Yeah - that 5 degrees makes a hell of a difference. I'd try a 30 degree secondary way before shelling out 30 quid on a new blade.

BugBear

 

[marku]

Thanks again for all the help.

I tried a secondary bevel and it did improve things however the iron still chips very quickly.

I think it might be time for a replacement as the rest of the plane is in such good condition.

 

[GazPal]

Is the edge actually chipping (How badly?) or are fine particles/slips flaking from it during use?

Record blades are normally good (Esp the older crucible steel ones), unless over heated/blued and softened during grinding. In which case an edge will tend to curl or indent rather than chip.

I suspect the problem could be related to the following;

Are you removing all of the burr from the edge during honing and stropping? If not, this can sometimes lend itself to the impression there's a flaking edge as you attempt to take shavings, but is simply a micron thick ribbon of surplus steel being sheared away from the edge by the timber during use, instead of ground away and severed via adequate honing and stropping.

Adding a secondary bevel to the grind angle definitely tends to improve edge retention. e.g. Grind angle at 25deg and hone at 30deg are a good baseline to work from. :wink:

Good sharpening practice - just like everything else - involves quite a diverse variety of techniques and I'd not chuck your blade quite yet/until you've determined whether or not the problem is technique related.

 

[matthewwh]

If you are thinking of ditching the blade you could try popping it in the oven after you take your roast out. Cook it at 200 whilst you are eating and see if that has any effect on performance.

If it's still chipping try it a smidgen hotter next time you have the oven on and work up until you get the performance you want. Don't overdo it though - it's a one way street.

Excess hardness should be resolvable without resorting to replacements.

 

[bugbear]

Thanks again for all the help.

I tried a secondary bevel and it did improve things however the iron still chips very quickly.

How fine a grit/stone are you going up to? Some research in the 1950's showed that small scratches left by sharpening can be the origin of fractures in use, and that more highly polished edges last longer.

BugBear