How to fix bent teeth on a vintage razor

Discussion in 'Articles' started by PLANofMAN, Jul 25, 2020.

  1. PLANofMAN

    PLANofMAN Paperboy

    Article Team
    First off, caveat emptor. This is done at your own risk. I've straightened exactly one tooth on a modern brass razor, so I'm not any sort of hands on expert when it comes to this topic. Indeed, I was reluctant to publish this article with as little hands on experience as I have, but felt the information needed to be available to the wet shaving public anyways.

    I've noticed a lot of misinformation on this topic across multiple forums for years. It's time to clear up some common myths and misconceptions about straightening teeth on vintage razors.

    It can be done, with minimal risk.

    The first question you need to ask, "Is the tooth bent down, or if an end tooth, down and inwards?" If the answer is "yes," then you need to make a choice on whether to proceed, or just leave well enough alone. The razor is fully functional as is, and the bent teeth are a cosmetic imperfection only.

    Broken outer teeth represent an actual shaving hazard. If the razor has sentimental, monetary, or historical value, you might be best off letting sleeping dogs lie.

    Rules for straightening teeth:
    1. If you can see a crease, crack, or fracture where the tooth meets the baseplate, don't try to fix it. It must be straightened and repaired by a jeweler or someone with equivalent skills. It will certainly break if you try to bend it.
    2. If you deviate from the following guide, you will break the tooth.
    3. If you don't have patience and steady hands, you will break the tooth.
    4. You might break the tooth anyways.

    "If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy nor yourself, you will succumb in every battle."

    Sun Tzu, The Art of War

    It's a fancy way of saying we are about to learn why brass gets brittle, or "Why does the tooth break when it gets bent back to the proper position?"

    The TLDR version:
    When you heat and cool brass it gets soft. When you move it, it gets hard and brittle again. If your brain is hurting, skip the bit in italics.

    Boring scientific bit:
    "Copper and copper alloys, such as brass, can only be hardened by work hardening. This is usually done by running a sheet between rollers, or it can be done by drawing (pulling a wire through a hole smaller than the diameter of the wire). Hardening can also be done by beating with a hammer, but the results will be uneven, to say nothing of the resulting uneven thickness. At some point the material becomes brittle, which may limit the amount of bending possible for your part. In a rolling plant, the sheets get hard after a few rolls, and so, they need to be heated (tempered) to soften them so the thickness can be reduced some more.

    Iron is also hardened by working, but the amount is limited. Hardening cannot be achieved by heating and quenching (rapid cooling) unless the carbon content is greater than 0.12%. This limit basically defines the difference between iron and steel. To go beyond this, other elements are added, creating alloys. On the topic of alloys, brass is an alloy of copper and zinc; bronze, is an alloy of copper with tin, phosphorus, aluminum, nickel or silicon.

    Aluminum can also be hardened, but this is mostly done by precipitation or solution hardening, where the material is kept at a certain temperature for period of time. The hardness is designated by a "T" code, as in 6061-T4, which is the most common grade of aluminum.

    We work in brass and copper in models because they are easy to work, easy to solder or braze, and are corrosion resistant. We could use stainless steels (there are many grades), but they tend to be quite hard, as anyone who has tried to drill and tap a 4-40 thread in stainless knows. Aluminum has some of the same properties of brass, but it's very hard to join, although I've seen some aluminum "solders'. Although aluminum is corrosion resistant, it does form a soft oxide layer that comes off easily.

    Probably more than you wanted to know, but now that it's been emptied from my brain, I have room to learn something else...."

    -lehmann from the model ship world forum

    I quoted this guy because he was able to put this stuff in layman terms and describe it a lot like I would. I didn't quote him because he's some kind of expert, though he might be.


    Old type Gillettes were made from softer sheet brass, and tend to be more forgiving when worked cold. The Gillette New onwards were made from a different type of extruded brass and the brass is harder. The New (and newer Gillette razors) must be annealed before bending.

    Tools of the trade:
    Hobby torch. At minimum, a gas station butane torch lighter, affectionately known as a "crack lighter."
    A better option would be a kitchen or brulee torch.
    The best option is a Bernzomatic TS8000 with a coleman propane cylinder.
    Screwdriver
    Very small pliers, preferably with no teeth. Jeweler's pliers wrapped in electrical tape are ideal.

    The minimum annealing temperature is a dull red glow in a darkened room. That's about 700°F. You can let it slowly cool or quench it in water. It doesn't matter either way. Some people heat it red hot, which is overkill. You want to keep the temperature between 700 and 2651°F. If it hits 2651°F, you can kiss your nickel plating goodbye. That's right around the maximum temperature of a brulee torch, and well below the maximum a Bernzomatic propane torch can produce.

    Heat, check, heat, check. You'll develop a feel for it over time.

    You only want to heat the tooth and the surrounding metal of the baseplate. It won't take long.

    Now you want to let it cool. You can either wait 5 to 7 minutes for it to cool enough to handle, or dunk it in water. It's a religion thing with brass ammunition reloaders, and they will often prefer one method over the other, to the point of heated discussions on the subject. Either way the end result is the same. The brass should be annealed enough to work.

    Carefully give it a little bend. Stop. Re-heat, cool down. Bend it a little more. Stop. Re-heat. Repeat. NEVER try to bend it while it is hot. NEVER bend more than once without reheating and cooling. After every bend, check for cracks. If you see a crack forming, see rule #1 above. The average tooth will take 3 to 5 heat and cool cycles to be back in position.

    Every time you move brass, it hardens. You want it to be malleable (soft) when you are moving it. Do not try to do it all in one go.

    If you've kept the temperature down to a reasonable degree (pun, lol) the plating will still be intact. If you've kept the temperature high enough, the tooth will also be intact. The razor will likely be covered in carbon and soot. It'll buff right out.

    If you follow these steps, you can save razors, and walk where other forum members fear to tread.

    These are tried and true techniques that have been used on 40+ razors (in a row, without breaking teeth) by members of other forums. This method is a combination of of me explaining the 'why' and other people's posts explaining the 'how.'

    If you do break the tooth, all is not lost. Take it to a mom & pop jewelry store, not a chain store. The jeweler there should be able to braze the tooth back on and polish it out as though it was never broken. You will need to get it replated at that point. If you are lucky, the jeweler will offer that service as well. If you are really lucky, the price will be comparable to the razor replating services, and the quality will be too.

    From "The handbook for machine shop and drafting room" 1914 pg. 975:

    "By heating brass to just below the temperature at which it would glow a dull red in a darkened room, brass can be shaped into difficult shapes, almost impossible, and to get shapes with square corners."

    [Brass begins to glow red at 840°F, what is called the 'Plum' color. At 900°F it has reached 'Dull Red.' Brass is annealed between 800°F and 1300°F. If worked while still hot, it cracks.]

    Author's Note: I researched this before attempting to repair a personal favorite razor, and after researching, decided to let a professional attempt the repair, because one of the bent teeth is creased.

    However, this research has turned into a spin off project between myself and Tom White. We attempted to turn Gillette old type razors into slants. That turned out to be a success, but since heat was not needed, kind of turned out to be a wash in regards to this article.

    Edit: Since heat is required for the thick Old types, but not the thin capped versions, I've been putting in some more research.

    Brass takes 1 hour to anneal at 600°F.
    In seconds at 800°F.
    Lead puts out poisonous fumes at 900°F.
    I think it is safe to say that we can assume Gillette used leaded brass in the 1920's.
     
    Last edited: Aug 6, 2020
  2. sparky5693

    sparky5693 Administrator Staff Member

    Administrator
    Very informative. Thanks!
     
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  3. Primotenore

    Primotenore missed opera tunity

    Article Team
    Good read and helpful. Me...I don't purchase vintage razors with bent teeth. ;)
     
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  4. Entasis

    Entasis Member

    I enjoyed this article and have saved it for future use. Thank you!
     
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  5. Jim99

    Jim99 Gold Water Shaver

    That’s very informative. Thanks!
     
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  6. PLANofMAN

    PLANofMAN Paperboy

    Article Team
    Me either. One of the reasons I was hesitant to publish this article. :)
     
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  7. brit

    brit in a box

    thank you Ryan.perfect if i score a rare gillette with bent teeth cheap or drop/damage one of my own..:)
     
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  8. PLANofMAN

    PLANofMAN Paperboy

    Article Team
    You know me. Always looking for new guinea pigs. :p

    Edit: and for everyone, seriously, if you do try this, post here and let us know what works and what doesn't.
     
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  9. feeltheburn

    feeltheburn Well-Known Member

    Nice article Ryan. I did straighten out the end teeth on an old type several years ago using the method you explained. It worked ok for me that one time but I was nervous about it.
     
    Last edited: Jul 27, 2020
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  10. PLANofMAN

    PLANofMAN Paperboy

    Article Team
    The late cooncatbob said (once rather famous across shaving forums), (best known for pioneering custom razor handles, and custom shaving accessories like Gillette psycho keys, and replacement Progress knobs).
    https://www.badgerandblade.com/forum/threads/can-a-bent-open-comb-tooth-be-straighten-by-hand.99559]

    I suspect hubris caught up to him there. Other members claim to have experienced no failures over the course of dozens of razors.

    I believe there are some possible reasons for this. The first possibility is that Cooncat didn't follow the recommended directions. The second possibility is that Cooncat tried to fix razors that most other people probably wouldn't bother trying to fix.

    I think he might have forgotten that brass and ferrous metals anneal the exact opposite of each other; and he may have tried bending the teeth while the metal was heated. That would cause a high failure rate.

    Annealing brass isn't a subject that gets talked about much, except in the 'hand loading' section of firearms forums, and possibly in a pipefitter or machining forum. Bob's post is ambiguous, because the post doesn't give us enough information. We don't know if he was heating the razor correctly or incorrectly.

    A dissenting voice is valuable for articles such as this one, especially when, as is certain to happen at some point, someone breaks a tooth. They can point to this post and say, "Bob was right."
     
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  11. PLANofMAN

    PLANofMAN Paperboy

    Article Team
    Of particular concern to me is the possibility of lead poisoning from vintage razors with the plating all worn off. Also, exposed brass can get surface deposits of lead when the razor is annealed, as the heat causes the lead to wick to the surface. Most brass made before 1984 (with the exception of Navel Brass, I think) contains about 2%-7% lead.

    I addressed this issue in a blog post in 2014, though that was related to concerns about brass from China that was being used in vaping devices. The following is the portion relevant to us.

    "Some brewers use brass fittings in conjunction with their wort chillers or other brewing equipment and are concerned about the lead that is present in brass alloys. A solution of two parts white vinegar to one part hydrogen peroxide (common 3% solution) will remove tarnish and surface lead from brass parts when they are soaked for 5 minutes or less at room temperature. The brass will turn a buttery yellow color as it is cleaned. If the solution starts to turn green and the brass darkens, then the parts have been soaking too long and the copper in the brass is beginning to dissolve, exposing more lead. The solution has become contaminated and the part should be re-cleaned in a fresh solution."

    More reading here:
    http://brewingrabble.com/resources/surface-lead.htm

    Edit: @jmudrick did some more research into this and he recommends 2.5-3 minutes in the solution. From my own recollections, I believe he is correct. 5 minutes is too long.
     
    Last edited: Aug 8, 2020 at 1:10 AM
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  12. PLANofMAN

    PLANofMAN Paperboy

    Article Team
    s-l400 (7).jpg
    This little guy had some issues. I was able to successfully bend all the bent teeth back into the proper places. I did not use the multiple anneal and bend sessions recommended, because this is a 1918 old type and is made from softer brass than later razors, so I wasn't too terribly concerned that I might break teeth. I did anneal it first.

    As far as worrying about the plating, it's not a concern here, since we are just heating the tooth and surrounding area. It only takes seconds.
     
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