centering blade issue

[decraew]

Hi Guys,

I have rescaled a razor using new plastic scales. I don't use pins but rather the fine screws from Microfasteners. The blade seems to be straight, so do the scales. Brash washers on the inside.

If I don't tighten up the nutt the blade is centered. However, if I tighten it up the blade moves away from the side of the screw (so badly it would hit the scales).

Any idea what might cause this ? I think I could solve it by adding a washer to the side away from the nutt but ... the solution's not very elegant and I would like to know what's wrong here.

Thanks y'all !
Wim

 

[Matt]

Well, geometry is simple - at least one of the surfaces involved isn't parallel to another ones. You've got four involved altogether:

(inner side of the left scale || left side of the blade /---/ right side of the blade || inner side of the right scale)

Of course, right/left choice is arbitrary, you get the idea. So your job is to identify where the problem occurs, and gently file something, most likely the scales. Of course, after second thought you might think, hey, they won't ever be perfectly parallel, because scales form a kind of wedge, wider at the side where the blade is, there is some tension, etc. Still - in imaginary situation where the end pin is unpinned - they need to be parallel.
This is my guess, though. Maybe Ray will drop in, he's a seasoned expert in rescaling (at least looking at his work confirms me about it ).

regards,
Matt

 

[rayman]

Thanks Matis. I have a set of scales I am working on today and will document the process, with photo's. Your issue is certainly with alignment, which is usually in the wedge end. I will try to make the process more understandable when I post next.

Ray

 

[Bart]

Your issue is certainly with alignment, which is usually in the wedge end.

So true. If the connection at the far (wedge) end is the slightest way out of true, one side of the scales may be marginally longer than the other. When everything is tightened together after that, the scales have nowhere to go than at one side. In essence, it's the scales that deviate and not the razor. Sometimes when the tang of the razor is out of true, you can actually turn that into an advantage, if you make the scales scew in a compensating way.

Something to ponder upon, while you await Ray's tutorial.

Best regards,
Bart.

 

[rayman]

Your issue is certainly with alignment, which is usually in the wedge end.

So true. If the connection at the far (wedge) end is the slightest way out of true, one side of the scales may be marginally longer than the other. When everything is tightened together after that, the scales have nowhere to go than at one side. In essence, it's the scales that deviate and not the razor. Sometimes when the tang of the razor is out of true, you can actually turn that into an advantage, if you make the scales scew in a compensating way.

Something to ponder upon, while you await Ray's tutorial.

Best regards,
Bart.

This is certainly something you can ponder on, but please don't act on it! I am almost convinced that most of the cracks we see in old scales, were caused by attempts at skewing the scales somehow to align them better.

I remember this old guy my physics teachers talked about, Newton. He said something about for every action there is.... well you know the ending. Consider a skewed alignment with the pivot hole on the tang. Once set like this, the blade will constantly open, and close, with pressure to the front of the pin on one side and to the back of the pin on the other. If your scales are old or thin, eventually a crack will form.

My solution would be to midigate this before we finalize the pinning.

Just my $0.02 USD.... Smile

Ray

 

[decraew]

Thanks for the input guys - a lot to think about. Solving the actual issue will be in the morning after a good coffee or 5

 

[rayman]

Here is a rough drawing of what is going on with the wedge end of the scales. Notice in the upper drawing, the pin is straight. In the lower drawing, the pin can't line up straight. This is where the problem lies.

There is a solution to this but that will come later.

Ray

 

[Bart]

As long as you know that it's prohibited on Coticule.be to write engenious posts, without turning them into a permanent article for our knowledge base... :

You're a master, Ray.

Bart.

 

[towliff]

This and the other recent post youve done for the rescale of the dovo (I have the exact same blade and is VERY tempting to redo like that ) are sheer genious!

Now, surely a very simple yet effective way to counteract the bending of the pin, which I'm planning to do when I get round to making some oak scales for my old sheffield blade Im going to buff up reaaaaaal goood, is to attach the spacer and a piece of wood the same dimensions as the tang of the blade to the scales using double sided tape, then drill the holes. That way, when drilling, the scales are essentially 'complete' hence the pins wont bend when you unstick the spacer and pin it

Ive never made scales, or restored a blade, but those are just some thoughts that seem like an obvious choice to make (for me anyway!) :thumbup:

 

[Matt]

Well...

The posts by Bart and Ray have revealed an utter ignorance of mine. Sorry for being so quick to advise. It just seemed so simple.

Lesson learnt. :sleep:

regards,
Matt

 

[rayman]

Well...

The posts by Bart and Ray have revealed an utter ignorance of mine. Sorry for being so quick to advise. It just seemed so simple.

Lesson learnt. :sleep:

regards,
Matt

Matt,
Sometimes questions like this are as new to Bart and I as they are to you or someone else. Remember, you are a member of a think tank here. We are not always looking for precise answers, but answers that stimulate our thinking, helping us to look at things differently than we normally do.

You have accomplished that here. Perhaps when I am finished showing you how I do this, you or someone else will provide an easier way to do some part of it. That is what we are looking for, and no one should feel immune to providing their input because they think it might be wrong. Nothing is wrong here and I do expect your hand to go up along with mine and others, as we progress through this and other topics.

So Matt, thanks for your input, and don't stop.

Ray

 

[decraew]

Allright people, got is solved !!

I actually contacted the person who sold me the scales, Steven from the invisibleedge.co.uk.
He told me it's a problem he's had before with this type (mass produced) of scales.

What he does to solve it:
put the scales in hot (not boiling) water for a few minutes.
quickly dry the scales, re-scale the blade and then bend the scales until correct and that until the scales have cooled down again.
Pretty simple really but you have to think about it I guess !!