(Topic ID: 113181)

Tamper Proof Gulmite Bolts...look familiar?


By Rody

4 years ago



Topic Stats

  • 40 posts
  • 13 Pinsiders participating
  • Latest reply 4 years ago by MikeO
  • Topic is favorited by 1 Pinsider

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    coldweldrep.jpg
    Gulmite no 8 screw.jpg
    Gulmite shank.JPG
    Gulmite screws.JPG
    Gulmite drivers.JPG
    Painting 6-27-2000.JPG
    Me May 1998.JPG
    Speakers 5-8-98.JPG
    tamper bolts.jpg

    #1 4 years ago

    Hey folks,

    One of the new games I just picked up has some unusual tamper bolts used to hold two halves of the gun mech together.

    I've not had any luck finding this 50's equipment noted anywhere.

    Does anyone recognize this?
    tamper bolts.jpg
    The top bolt is the male half of the connection (unknown interface), the bottom is the female side which looks like a 12 point Ferris.

    Ideally I'm looking for the name of said interface and if there is a tool available.

    Crossing fingers in hope...

    rody

    Post edited by Rody: Added Proper description to Title

    #2 4 years ago

    Ha, welcome to the world of Gulmite screws! The Gulmite drivers are a challenge to locate, but come in different sizes (#10 being the size used on Bally Skill Rolls). These screws were used on oddball stuff like drive-in speakers, bus seats, and apparently some arcade stuff.

    #3 4 years ago

    Awesome Dirt...the search begins.

    rody

    #4 4 years ago

    those gulmite drivers appear to be unobtainium...

    wonder if some ever pop up on fleabay?

    #5 4 years ago

    They do occasionally appear on ebay. Expect that there are folks already running that search.

    #6 4 years ago

    Very interesting thread-thks for the info DF. This fellow in bus restoration has a neat out using a dremel and assuming the gulmite driver set is rarely, if at all, obtainable.

    Not sure whether this guy uses handwash!!

    #7 4 years ago

    I was able to get my #10 gulmite driver on ebay a couple months ago after a year of searching. Expect to pay $20-$60 ?

    #8 4 years ago

    Rody - what it the game ?

    #9 4 years ago
    Quoted from jeffc:

    Rody - what it the game ?

    Bally Spook Gun...the cast aluminum frame is broken, cracks in several places. Need to take it apart into it's two halves to repair it.

    rody

    #10 4 years ago

    Here is a capture from Nomadicista with the most complete info I've run across:

    Frequently, I am contacted by owners of Crown coaches and asked how to acquire a set of Gulmite drivers so that the fasteners holding their coaches together can be removed and/or replaced. Each time, I do my best to be helpful, but the fact is that these tools are elusive at best and unobtainable at worst. Therefore, I’ve decided to put everything I know about Crown Head screws and the associated driver tools down in one place so that I can refer inquiries to a central topic on the subject. Perhaps others have found a source for these tools and can append that information here, making the topic thread even more valuable.

    In the "Crown Advisor" on this site, I mention the following:

    If you are going to work on a Crown, you need a special set of tools to drive the "Crown Head" screws that hold most of the sheet metal and trim together. These screws have 24 little points around the head, and NOTHING ELSE but a Crown Head tool will work on them, except vise-grip pliers, and then not very well. I bought a set, which is a #6, #8, #10, #12, & ¼" for $78.00 from the local fastener supply house. They had to special order them from L.A. I suggest that you find a set and purchase them ASAP, as they will save you hours of frustration and wrecked projects. This assumes that your bus used them in its construction. They are quite good quality, and I have been putting them back into my new construction when I can, as I have thousands.

    without supplying any additional information. There was a reason for this, there is very little else to impart. My set was purchased through Eugene Fastener, 360 Wilson St. Eugene, Oregon, 97402. This was in 1995, and at the time, I knew everyone in the building by name, including the owner, Jeff. He put in a few calls after surveying the sample screws I provided, and eventually was told after describing them that he wanted "Crown Head drivers". The set that I received several weeks later looked like it had been picked out of all corners of a warehouse, as the photo later in this topic shows, nothing matches.

    For a number of years, I used to refer people to West Coach of Chino, California to purchase drivers. I was once contacted by a representative of West Coach and told that sets of drivers were available for sale:

    Don L wrote:
    Give me a call about crown parts...we have the gulmite sets...but only 6 10 and 14...
    west coach corporation
    13790 redwood st
    chino ca 91710
    909-464-1025
    parts dept
    chuck ext 13

    Hmmm, many of the fasteners in my bus were #8, and they weren't offering that size. Still, a partial set would be a start. Unfortunately, I recently found out the West Coach has gone out of business, leaving no forwarding address.

    Here is my collection of Gulmite drivers, with a sample screw for each size:

    #6 drivers (two)
    The far left hand diver is one that I had custom made, more on that later. The right hand one was a badly rusted driver that I found inside one of the window cavities of the bus while I was tearing it apart. A lucky find. It has a ¼" hexagonal shank that chucks up in a drill nicely.
    #8 driver, part of the set I ordered. It originally came with a plastic screwdriver handle that wasn’t attached to the shaft very well. I got tired of using it by hand to remove the several thousand fasteners in the bus, and used a hacksaw to chop off the handle, turning it into a straight shank that could be chucked into an electric drill.
    #10 driver. This one also had a plastic screwdriver handle, but the driver tip kept falling off the shank and I was afraid I’d lose it, so I silver brazed it onto an old Phillips or square bit so I'd have the hexagonal shank.
    ¼" driver. This one came with an attached adaptor that engages with a ¼" square socket set bit. Its shown with the adapter disengaged at the rear. There were only about a dozen ¼" Crown Head screws in my bus, I seem to remember most of them were in the emergency door hinges, and some had been used to attempt to repair some of the metal fatigue in my walls.
    #12 driver (not shown). I found this driver only after I took the photo partly because I couldn't find any samples of that size screw. I don't know that I've ever used this driver bit on my bus. It also has the ¼" square socket set drive end.

    The #8 driver in the photo above contains an interesting artifact. Stamped into the metal shank is the following:

    U.S. Patent Gulmite 2103944

    This patent number does appear to be valid, and a quick search of Google brought up some results referring to it as being a patent for a "security screw removing tool". Further research may turn up a patent holder who might be able to direct you to a manufacturer or drawings or plans that would allow the tools to be duplicated (assuming that the patent has expired).

    So, if sets of drivers (or even individual drivers) aren't available for purchase, how about having some made?

    The original tools I purchased had been broached in order to create the internal splines. This is not a process that can be duplicated at home, and while it might be possible to recreate the drivers with a metal lathe and properly formed cutter bits, it would be a laborious process, one that would be prone to trial and error until you got it right.

    After broaching, metal is usually heat treated to increase it's hardness for tool usage, but my purchased tools apparently were not sufficiently hardened, because as I used them, the internal splines wore down, a process that was accelerated if I was not careful to prevent the driver bit from slipping on the screw heads due to misalignment or insufficient pressure. Several of my bits have had to have the ends ground down to expose more of the undamaged internal splines on order to continue to be useful.

    The set that I purchased did not come with a #6 driver bit. Since my coach had quite a number of these size fasteners in the interior, I had one made so that I could remove the trim and panels that were attached using them.

    At the time, one of my clients was a machine shop which had two EDM wire cutting machines. The older of the two machines was rather decrepit, and I was occasionally called in to troubleshoot its electronics.

    I approached the operator of the machine and explained my need. (Rather than attempt to describe EDM machining, I'll refer you to the link above.) He used a very old optical scanner that looked like a giant view port from the Wizard of Oz to enlarge the profile of the head of my sample screws to fill the viewer, about two feet in diameter. Then, by some process I didn't witness, a program was written that directed the newer of the two machines (identical to the one pictured in the Wiki page) to cut a driver out of a billet of metal using the EDM process. The result was a hollow shaft that was splined all the way though. This tool is made from very hard tool steel metal, and will probably never wear out. I ground some flats on two sides so that I could put an end wrench on it to back out some stubborn screws.

    If I was going to have another tool made, I think that I'd have the splined billet cut into wafers about ¼" thick, and weld those pieces to a shank of some sort. The long driver with the spline all the way through works well enough, but because the hole isn't "blind" there is nothing to prevent the screw from extending into the body of the bit. This makes putting screws into material difficult, as there is nothing to back up the screw head and give you a purchase to hold the screw against the material as you drive it in. All of the Crown machine screw have tapered self-tapping cutter threads at the tip, and are made of very tough material. They thread themselves into any material given the proper size pilot hole.

    Another EDM process for making these tools called "sink cutting" was proposed by Gary, a Crown Coach owner who is very inventive. He supplied his machinist with several clean, non-damaged screws and those were used as the cutting electrode:

    Gary S. wrote:
    Just EDM'd my final Gulmite driver tonight, this time out of oil-hardening steel. I stripped the last one that I made from a socket. The new tool works perfectly. It takes on average 6 good screws to EDM out a tool... the first few rough it out and the last few bring it into tolerance. Takes about 10 minutes once it's set up. SO now I have a complete set! Whoopee!!

    I mentioned to him that such tools might be marketable, to which he replied:

    Gary S. wrote:
    I probably will make em. If I can find drawings for the screw heads, it would make life much easier for my toolmaker- he likes to work from drawings more than from de-engineering. But he wants to make a carbon tool and then we could make as many drivers as we want. The 6 screws were just a quickie but it worked really well.

    As far as I know, he never made any additional driver sets.

    There you have it, EVERYTHING I know about Gulmite fasteners, including pictures, links, fabrication suggestions, and hints as to where to research out more info. If anyone has a source for these tools, or decides to have a few dozen sets made and wants to start selling them, go for it, I am easy to please, only a small royalty is due for my diligent research.

    #11 4 years ago

    I had run across that site and info back when I started my search too. All dead ends now, that I could tell.

    Best bet seems to be to haunt eBay. Sometimes sets appear, sometimes a single driver. Prepare to spend some bucks for one. Or, hack it out and replace with a regular #10 screw. It took me about six months to find one.

    Makes sense the Bally Spook Gun would use them. They seemed to like them on games from that period.

    #12 4 years ago

    The one time WD-40 is permitted near a game.

    #13 4 years ago

    My dad was a machinist and we have a complete machine shop in my moms basement.

    I'm pretty sure there is a full set of these there. Plus countless other gems. My father never saw a tool he didn't like. Plus he was so good he was able to make and then harden just about anything.

    When I go up for the holiday I'll grab them.

    Every time I go up I snatch some old specialty tool that no one uses anymore.

    If there are there I'd be happy to lend them to other Pinsiders as long I get assurance that I'll get them back.

    #14 4 years ago

    Gulmite head screws were used on drive-in theater speakers, Crown school busses, and Maytag washing machines. Since I used to work in drive-in theaters repairing the speakers, I bought a set (#8 and #10 sizes) from the drive-in theater speaker manufacturers (there were several) back in the early 1980's when I could buy the drivers for just $5 each.

    I still have those drivers and a bag of Gulmite # 8-32 screws. I'm hanging onto those drivers since I still repair some drive-in theater equipment.

    #15 4 years ago

    A good image of the gulmite screwhead (8/32) and tool. Seller sells the screws but apparently not the tool!!

    ebay.com link » 20 Drive In Speaker Specialty Security Screws Gulmite Head Hard To Find New

    #16 4 years ago
    Quoted from fflint_18:

    My dad was a machinist and we have a complete machine shop in my moms basement.
    I'm pretty sure there is a full set of these there. Plus countless other gems. My father never saw a tool he didn't like. Plus he was so good he was able to make and then harden just about anything.
    When I go up for the holiday I'll grab them.
    Every time I go up I snatch some old specialty tool that no one uses anymore.
    If there are there I'd be happy to lend them to other Pinsiders as long I get assurance that I'll get them back.

    that would be really cool bert... be nice to have a set of those nearby just in case...

    #17 4 years ago

    Had to resort to cutting a slot to remove the gulmite screws...fortunately they were not near as rusted in place as the condition of the heads would indicate, came out easily without any penetrating oil (or WD-40).

    Thanks all for adding to my education

    rody

    #18 4 years ago
    Quoted from KenLayton:

    Gulmite head screws were used on drive-in theater speakers, Crown school busses, and Maytag washing machines. Since I used to work in drive-in theaters repairing the speakers, I bought a set (#8 and #10 sizes) from the drive-in theater speaker manufacturers (there were several) back in the early 1980's when I could buy the drivers for just $5 each.
    I still have those drivers and a bag of Gulmite # 8-32 screws. I'm hanging onto those drivers since I still repair some drive-in theater equipment.

    Kens' post twigged my thought process & I just purchased a pair of drive in theatre speakers for resto to use with my Seeburg wallbox. I am not sure whether they will contain the dreaded 'gulmites'!

    http://www.ebay.com.au/itm/Drive-in-speaker-parts-NTS-brand-suit-restoration-or-display-as-is-/331419888993?ssPageName=STRK%3AMEWNX%3AIT&_trksid=p2047675.l2557&nma=true&si=ccqL11%252FQctdpI%252BI6Rr%252FEoDEQYBo%253D&orig_cvip=true&rt=nc

    I thought they would add some nostalgic charm from the EM era to my games room. Anyhow the seller David Kilberry was an example of a high integrity (in Australia we would say 'a damn good bloke') seller. After corresponding he said he would throw in an unbroken hook mechanism as part of the sale. He also has reopened a drive-in theatre in our State of Victoria:

    http://www.lunardrive-in.com.au/

    and has previously been a large seller of pins & jukeboxes trading as Chicago Amusements-it is indeed a small world.

    #19 4 years ago
    Quoted from KenLayton:

    Gulmite head screws were used on drive-in theater speakers, Crown school busses, and Maytag washing machines. Since I used to work in drive-in theaters repairing the speakers, I bought a set (#8 and #10 sizes) from the drive-in theater speaker manufacturers (there were several) back in the early 1980's when I could buy the drivers for just $5 each.
    I still have those drivers and a bag of Gulmite # 8-32 screws. I'm hanging onto those drivers since I still repair some drive-in theater equipment.

    You repaired them? Why? Putting up a couple of tin cans with string between them would have improved the audio quality...

    #20 4 years ago
    Quoted from EMsInKC:

    You repaired them? Why? Putting up a couple of tin cans with string between them would have improved the audio quality...

    Ahh that was part of the magic of that era-did things need to be perfect but in any case at that time who cared about the sound! There were other more pressing horizons!!!

    #21 4 years ago

    Yes, I kept all the speakers running and sounding good at both the Sunset Drive-in Theater (now demolished) in Tumwater, Washington and the Skyline Drive-in Theater (still operating) in Shelton, Washington. Properly maintained speakers as well as rebuilt tube amplifiers sound real good at drive-ins.

    Here's some pictures of me in the booth at the Skyline in 1998, a couple of rebuilt speakers on a brand new junction box in 1998, and when we had the screen painted in 2000 (the white picture area of the screen is 40 feet tall by 84 feet wide).

    Speakers 5-8-98.JPG
    Me May 1998.JPG
    Painting 6-27-2000.JPG

    #22 4 years ago
    Quoted from EMsInKC:

    You repaired them? Why? Putting up a couple of tin cans with string between them would have improved the audio quality...

    Coming from a guy with an EM collection, I find your question very disconcerting. Why not trade in all of your EMs for what, one DMD, maybe two? The reason I am 36 and have an impressive vinyl collection is because the time period was when music was good. Songwriters mattered. The sound is true to the era. Imagine sitting in the first drive in with a girl, the top down, and the scratchy speakers. This isn't today where you can download a movie on your phone. This is "how frickin amazing is the world we live in where I can drive my car into a lot and watch a movie on a 40 foot screen." We repair old things because we can, and we should.

    #23 4 years ago

    Gulmite screws and driver are patent # 2103944:

    http://www.google.com/patents/US2103944

    I have a #8 and a #10 driver. Both have no manufacturer's name on them anywhere, just the patent number stamped into the shank. I bought one of them from Drive-In Theater Manufacturing Company (later called Systems and Products Engineering Company, SPECO) in Kansas City. They were the largest drive in theater speaker manufacturer and parts supplier, but went out of business last year. Kansas City used to be known as the drive-in theater speaker capital of the world.

    Gulmite drivers.JPG
    Gulmite screws.JPG
    Gulmite shank.JPG
    Gulmite no 8 screw.jpg

    #24 4 years ago

    Great post, story & pics Ken! What was the width of the roller to paint that screen?

    #25 4 years ago
    Quoted from wayner:

    Great post, story & pics Ken! What was the width of the roller to paint that screen?

    It took them two days. First day was all pressure washing. Second day was spray painting. I think the final bill was around $5,000. The Skyline's screen is made of corrugated sheet metal.

    #26 4 years ago
    Quoted from KenLayton:

    It took them two days. First day was all pressure washing. Second day was spray painting. I think the final bill was around $5,000.

    I'm in the wrong business. I would powerwash and spraypaint that screen for a grand.

    #27 4 years ago
    Quoted from eeperjesi:

    I'm in the wrong business. I would powerwash and spraypaint that screen for a grand.

    It would cost you $1000 just in paint lol.

    #28 4 years ago

    I guess you don't get the discount on paint that I do.

    #29 4 years ago
    Quoted from eeperjesi:

    ... We repair old things because we can, and we should.

    Reminds me of this poster which I have hung in my workshop:
    https://www.ifixit.com/Manifesto

    #30 4 years ago

    Is this what you were looking for?

    ebay.com link » Gulmite Wringer Washer Tool

    #31 4 years ago
    Quoted from jeffc:

    Reminds me of this poster which I have hung in my workshop:
    https://www.ifixit.com/Manifesto

    That is awesome. I will put one up in my shop, but only if I can make it out of something else.

    #32 4 years ago
    Quoted from Spyderturbo007:

    Is this what you were looking for?
    ebay.com link » Gulmite Wringer Washer Tool

    That is for a Gulmite, but it's for a larger size screw. Need a #10 size for the Bally stuff.

    #33 4 years ago
    Quoted from Spyderturbo007:

    Is this what you were looking for?

    Unfortunately, there are many sizes of gulmite heads, the ones used for the Maytags are not the same as used in the early Bally games.

    r

    #34 4 years ago

    Ken please don't take this the wrong way, but every time I see your pic, I want your hs initials to be "yuuuup!"

    #35 4 years ago
    Quoted from Rody:

    Unfortunately, there are many sizes of gulmite heads, the ones used for the Maytags are not the same as used in the early Bally games.
    r

    Every size of these are available from Snap On tools. Some German cars are using these for their door hinge bolts.

    #36 4 years ago
    Quoted from 0geist0:

    Every size of these are available from Snap On tools. Some German cars are using these for their door hinge bolts.

    Link?

    #37 4 years ago

    No luck with the Snap on site which on my short experience is far from 'snapping on' during the search process.

    As I have ordered a couple of drive in theatre speakers (NTS) I am unsure whether they will contain the gulmites but I have given a solution some thought.

    Is it not possible to take a short length of mild steel or stainless tubing with maybe a ml or 1/16 wall thickness which is a neat fit over the head of the gulmite screw (depending whether an 8 or a 10) and then either cold or hot nip the end of the tube with a small cold chisel into the gulmite crevices. There may then be a need to slip a further neat fit tube over that to prevent distortion during tensioning or detensioning. The tube can then have a T handle provided.

    To me this is a simple solution which should work given it seems near impossible to acquire the specialist tool apart from estate sales.

    #38 4 years ago
    Quoted from wayner:

    No luck with the Snap on site which on my short experience is far from 'snapping on' during the search process.
    As I have ordered a couple of drive in theatre speakers (NTS) I am unsure whether they will contain the gulmites but I have given a solution some thought.
    Is it not possible to take a short length of mild steel or stainless tubing with maybe a ml or 1/16 wall thickness which is a neat fit over the head of the gulmite screw (depending whether an 8 or a 10) and then either cold or hot nip the end of the tube with a small cold chisel into the gulmite crevices. There may then be a need to slip a further neat fit tube over that to prevent distortion during tensioning or detensioning. The tube can then have a T handle provided.
    To me this is a simple solution which should work given it seems near impossible to acquire the specialist tool apart from estate sales.

    I had no luck finding anything that would work on a Gulmite screw on the Snap-On site as well. Guessing maybe they thought the spline driver was the same? (it's not, however).

    There are 21 points around a Gulmite crown head. Good luck.

    2 weeks later
    #39 4 years ago

    I am in the process of restoring two NTS drive in theatre speakers for use with my game room Seeburg wallbox. Fortunately these speakers did not contain the 'gulmite screws' but each screw was rusted in there thread socket and required to be drilled out and re-threaded. On one speaker cover a screw head orifice had been damaged preventing the retention of the screw head. Not sure whether anyone has tried the product 'Cold Weld' which is a two part epoxy for metal repairs.

    http://www.supercheapauto.com.au/online-store/products/Permatex-Cold-Weld-Bonding-Compound-57G.aspx?pid=129919#Recommendations

    Anyhow I used the product and was pleasantly amazed by how well it worked. It enabled me to rebuild the orifice, provide a new screw hole and provide a chamfer for the screw head. I thought it was terrific and clearly has many applications in our hobby.

    coldweldrep.jpg
    1 week later
    #40 4 years ago

    If you traffic the late model pinball restoration threads you will find the metal mender products out there are utilized often to rebuild a worn kick out hole. They then touch up and clear or cover with a surface protector made by Cliffy or others.

    I've used metal epoxy to build up the edges of playfield holes on a Dr. Who and a Creature From The Black Lagoon. The fixit creativity is alive and well in all sides of the pinball hobby.

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