Dear OldMiniBikes members, I am currently working on fiberglass molds for thermo/vacuforming the fenders, chain guards, and cowlings needed for my Fox Campus restorations. One of the requirements is a series of .010" dia holes drilled into the molds to allow any trapped air to be drawn out. For those of you who have never seen .010" hole; it is approximately twice the diameter of a human hair. My first thought was to try a Dremel too at various speeds. Four broken bits in two minutes convinced me that that wasn't going to work. My second attempt was to use a pin vise turned only with my fingers. Using various turning speeds and pressures left me with a pile of twenty or more broken hss and carbide bits. Obviously that wasn't going to work either since most of the bits broke off flush with the surface of the mold and couldn't be extracted. After a week or two of sleepless nights I finally came up with a solution and it works beautifully. Since almost EVERYONE has a need to drill a .010 dia hole at one time or another; I thought I'd share my method with you. To give you an idea of what I'm working with here; pic#1 shows a .010" dia drill bit placed next to a penny. In order to end up with a .010" dia hole I started out by drilling a larger .035" dia hole. The .035" dia bit was stiff enough to drill through the fiberglass without snapping or breaking. Pic #2 shows my pin vise with the .035" bit installed and the smaller .010" dia bit to the left of it. Pic #3 shows the pin vise drilling the larger .035" dia hole. I drilled two holes side by side so that I would be able to compare the finished .010" hole with the original one that was .035" dia. See pic #4 After the hole is drilled; clear tape (like in pic #5) is placed over the good side of the hole that needs to have its diameter reduced. To be continued:
Drilling a .010" dia hole continued: From the backside; the hole with the tape is filled with tooling gel coat. A pin of the desired diameter (in this case .010") is then inserted into the gel coat filled hole and pushed through the tape on the other side like in pic #6. In my case, the bristle from a wire brush turned out to be exactly .010" dia. Don't forget to lightly grease the bristle with vaseline before inserting it into the hole. Makes removal a snap. Once the gel coat has dried you can remove the tape like in pic #7. Using a pair of pliers the bristle is removed and you have a rough hole like in pic #8. A little touch up with 1000 grit paper smooths out the rough edges and you are now the proud owner of a perfect .010" dia hole. Pic #9 shows a comparison of the new smaller hole with to original one. That black strand between the two holes is a human hair. Pic #10 compares the old and new holes to a straight pin. Now I just have to do this 75 more times and I will be ready to make fenders. Thanks for looking. Ogy
Salt, "Can't do it" sounds like common pessimism rather than common wisdom. The following words are hanging on my wall and they have served me well for the past 45 years: A great deal of talent is lost in the world for want of a little courage. Every day sends to their graves obscure men and women whom timidity prevented from making a first effort. Who, if they could have been induced to begin, would in all probability have gone great lengths in the career of fame. The fact is, that to do anything in the world worth doing, we must not stand back shivering and thinking of the cold and danger, but jump in and scramble through as well as we can. Ogy
kenny, I found a small family owned thermoforming company out in Pittsburgh who is willing to form my parts on a time and materials basis as long as I made the molds. First I made an exact replica of my fender out of wood, body putty, etc. That pattern was taken to a shop where a fiberglass female mold was laid up. After I drill the weep holes in the fiberglass molds they will be taken to the vacuforming shop and the parts will be formed. I've found companies who have the facilities to drill small holes like these. The problem however, is finding one who is willing to take on such a small project. That's why I decided to do my own drilling. If you can come up with an alternative, I would certainly like to hear about it. Thanks for writing. Ogy