# Is that a crack or a scratch?



## mwebster51 (Jun 9, 2020)

Hi Guys, not sure if you can help me with this or not but I thought I would ask. I restore very old Stanley metal hand planes for resale. The design of these planes is such that there is a week spot in the cast iron bodies at the opening where the blade comes out. The opening is called the mouth or throat. What happens to some of these planes is that a tear develops at one or both corners of the mouth where the metal is very thin. The frog, (the component that the blade is mounted on) is screwed down onto the plane body. It has a rear mounting surface and two front paws that land just behind the trailing edge of the mouth. As the screws are tightened and in some cases over tightened, the paws press on the rear side of the mouth and the metal gives way at one or both corners causing a split or tear. The thing is... if this occurs, the plane is never right again and for me unsellable. These tears are sometimes very obvious, other times it is extremely hard to tell if it is a scratch or the beginning of a tear. I have tossed plane bodies becase I couldn't determine it I had a tear or a scratch. Any techniques you know of that would help me determine if I am looking at a tear or a scratch? I have had some success applying solvent to the area and the "crack" can sometimes be more apparent as the solvent seeps back out.  I assume the industry has X-ray methods, but for me that is not practicle. Any suggestions base on your backgrounds in metal working? The attached photo shows a short faint line radiating down and slightly outward on the lower right rear of the mouth. I am pretty sure it is the beginning of a tear.
Thanks


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## dirty tools (Jun 10, 2020)

You can use a dye penetrating flui. It will allow you to tell the difference


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## mwebster51 (Jun 10, 2020)

dirty tools said:


> You can use a dye penetrating flui. It will allow you to tell the difference


Sorry if this is a supid question, I am a woodworker not a machinest. How does the dye penetrating fluid behave differently with the scratch versus a hairline crack. Does it continue to seep out of a hairline crack and the scratch just won't hold the dye if you wipe it off?


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## benmychree (Jun 10, 2020)

Dye check; clean, apply penetrant, apply developer, the result is obvious to the eye, a red stain develops through the white developer.


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## mwebster51 (Jun 10, 2020)

I will check it out! Thanks for the suggestion.


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## benmychree (Jun 10, 2020)

mwebster51 said:


> Sorry if this is a supid question, I am a woodworker not a machinest. How does the dye penetrating fluid behave differently with the scratch versus a hairline crack. Does it continue to seep out of a hairline crack and the scratch just won't hold the dye if you wipe it off?


the dye would not show through a scratch, significant amounts of the dye seep into the crack, and the developer draws it out.


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## mwebster51 (Jun 10, 2020)

Got it I will try to get my hands on some Thanks


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## mwebster51 (Jun 10, 2020)

Is this what the product you are referring to? I wouldn't need a large quantity. Is this the least one can expect to pay for a small kit? https://www.amazon.com/Dye-Penetran...words=dye+penetrant+kit&qid=1591763634&sr=8-2   Thanks again


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## rzw0wr (Jun 10, 2020)

As an old woodworker I would say no bigger than is is I would not worry about it.
It is at the throat and most likely a scratch. There is no pressure in that area.

Is this a Stanley?


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## mwebster51 (Jun 10, 2020)

Yes it is


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## mmcmdl (Jun 10, 2020)

I yanked all the cover plates off the power washer today . I have a leak . So I have the same question . A crack , or a break in the pipe . 

The zero turn is finished , basicly a new machine . I replaced the motor , every electrical component and every wire . This was a strange event . I could not diagnose the electrical problem .


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## mwebster51 (Jun 10, 2020)

Sound like a tough one


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## Martin W (Jun 10, 2020)

It will be a crack. They are prone to that right there. My Baily #5 has had a crack there since I have had it . Probably 40 plus years. Doesn't affect use but don't drop it on the floor. I had a Baily #7 that fell off the bench and broke in half.
My planes get used a lot. Not with solid wood as much. We do a lot of commercial millwork that is laminated. Use the planes for seaming the plastic laminate together.
Cheers
Martin


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## Old Mud (Jun 10, 2020)

Webster you might try here also. https://www.fastenal.com/product;js...86-c0d73327934b?query=dye+penetrant+kit&fsi=1


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## mwebster51 (Jun 10, 2020)

Thanks for the link!


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## vocatexas (Jun 10, 2020)

If you have a parts store or shop that does engine rebuilding you could probably pay them a few dollars and have it magnafluxed to check it for cracks.


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## mwebster51 (Jun 10, 2020)

I have not been around metal work or engine rebuilding type of work in my life. I just assumed magnafluxing was something manufacturers with deeper pockets did. I just know the word and the general purpose. So small shops have that capability also....good to know Thanks.


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## pontiac428 (Jun 10, 2020)

@mwebster51, it seems to me that you are concerned with quality control on the planers that you restore.  It makes sense to check them all for this fatal flaw that would have a customer demanding a return on their money.  As has been said, dye penetrant (magnaflux) is the tool for checking cracks.  It's not hard, and it's not expensive to do at home.  Here is some info:
https://www.magnaflux.com/Magnaflux/Blog/Dye-Penetrant-Infographic 

I think it would be worthwhile tool to add to your shop.


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## mwebster51 (Jun 10, 2020)

pontiac428 said:


> @mwebster51, it seems to me that you are concerned with quality control on the planers that you restore.  It makes sense to check them all for this fatal flaw that would have a customer demanding a return on their money.  As has been said, dye penetrant (magnaflux) is the tool for checking cracks.  It's not hard, and it's not expensive to do at home.  Here is some info:
> https://www.magnaflux.com/Magnaflux/Blog/Dye-Penetrant-Infographic
> 
> I think it would be worthwhile tool to add to your shop.


I am planning to purchase. It will fun to learn a new skill


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## mwebster51 (Jun 10, 2020)

pontiac428 said:


> @mwebster51, it seems to me that you are concerned with quality control on the planers that you restore.  It makes sense to check them all for this fatal flaw that would have a customer demanding a return on their money.  As has been said, dye penetrant (magnaflux) is the tool for checking cracks.  It's not hard, and it's not expensive to do at home.  Here is some info:
> https://www.magnaflux.com/Magnaflux/Blog/Dye-Penetrant-Infographic
> 
> I think it would be worthwhile tool to add to your shop.


Is there any reason to think this product is inferior to the Magnaflux product? https://www.fastenal.com/product;js...86-c0d73327934b?query=dye+penetrant+kit&fsi=1


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## Old Mud (Jun 10, 2020)

I think not, Dye Penetrant Kit: Solvent removable Meets AMS 2644, Meets ASME section V.


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## pontiac428 (Jun 10, 2020)

mwebster51 said:


> Is there any reason to think this product is inferior to the Magnaflux product? https://www.fastenal.com/product;js...86-c0d73327934b?query=dye+penetrant+kit&fsi=1


The description says the Fastenal product meets AMS 2644 and ASME section V, so yes, I would say that they are, for all intents and purposes, equivalent.  The technology is getting old, and I'm sure the patents have expired.  For your non-aerospace application it's probably difficult to go wrong.


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## mwebster51 (Jun 10, 2020)

Old Mud said:


> I think not, Dye Penetrant Kit: Solvent removable Meets AMS 2644, Meets ASME section V.


Thanks for your response!


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## pontiac428 (Jun 10, 2020)

One more:  https://www.magnaflux.com/Magnaflux/Products/Aerosol-Comparison


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## mwebster51 (Jun 10, 2020)

pontiac428 said:


> One more:  https://www.magnaflux.com/Magnaflux/Products/Aerosol-Comparison


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## mwebster51 (Jun 10, 2020)

Thanks again!


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## mwebster51 (Jun 14, 2020)

I purchased the kit from Fastenal and gave it a try today. I am wondering if technique can significantly affect the results. The Magnaflux product was nearly 2x price and not knowing much about the method I was a little afraid to invest a lot for my first attempts.  After having tried a few fine cracks today, or at least what I thought were fine cracks, I am wondering is the penetrant is too thick to work well for this application. Is a more expensive version thinner or is the fluorescent version thinner and/or more sensitive. I suppose that I thought were very very fine cracks could be just scratches but I was pretty sure they were going to show up as red lines with the devloper. Any thoughts?


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## matthewsx (Jun 14, 2020)

Technique will make a difference, get a part you know is cracked and give it a try so you can see what it looks like. Like anything else practice makes perfect, or at least competent....

John


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## mwebster51 (Jun 14, 2020)

matthewsx said:


> Technique will make a difference, get a part you know is cracked and give it a try so you can see what it looks like. Like anything else practice makes perfect, or at least competent....
> 
> John


Thanks for responding John. I did just that on a couple parts. It seemed like if the crack was pretty obvious the penetrant showed up fine. If I had a really really thin crack, it didn't seem to show up after the developer. Again the penetrant dye seems pretty thick to me, are most the penetrants on the thick side? The area where the crack develop is fairlhy thin. Will that make the method less sensitive? Again should I expect a product like Magnaflux to be more sensitifve?


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## matthewsx (Jun 14, 2020)

I don't have experience with that specific product and the application I had in the past was race engine parts so less room for error. Since you're selling the planes just doing the check for anything major is probably sufficient. 

You might want to check with your local automotive machine shop, they might be willing to do a batch for you at less then supplies will cost. I have no idea how many of these things you do every year but I'm fairly confident you can figure out the process with practice.

John


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## mwebster51 (Jun 14, 2020)

matthewsx said:


> I don't have experience with that specific product and the application I had in the past was race engine parts so less room for error. Since you're selling the planes just doing the check for anything major is probably sufficient.
> 
> You might want to check with your local automotive machine shop, they might be willing to do a batch for you at less then supplies will cost. I have no idea how many of these things you do every year but I'm fairly confident you can figure out the process with practice.
> 
> John


Thanks for the help and suggestions I appreciate it!


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