I am making new inserts for a coil box and am wondering why the two outer channels that are cut into the vertical panel have a slight step in them. The second and third channels don't have these relief rabbets. What is the purpose?
Why make when an excellent repro is available from Fun Projects that is moisture resistant? I can understand wanting to know why, but for the time it takes, I'd get the kit.
I wondered about that also, I don't think all had that feature. I did not see a reason for the step unless it had to do with the manufacture process. I did not see a need for the step cut and just cut the groove for the contacts when I made mine. Just match the main slots to your old wood and watch your screw holes, there are left side and right side to the contacts. I clamped the old wood to the new modern material one I was making to get the screw holes in the same place.
John Regan makes the inserts from the factory drawings.
There is a reason for everything as these cars were designed by engineers. For example, if I recall correctly John said that the interior walls of the inserts actually have a slight taper or curve so as you push the coil into the box, they get tighter (I hope what I typed makes sense - it's hard to articulate).
They may have been designed by engineers but assembled by dozens of 'cottage industry' folks living in close proximity to Dearborn.
I very much doubt piece-work was farmed out to laborers outside the factory.
Its to help you insert coils from the ends of the coil box by tilting them in. This is the way you have to insert them when you have low overhead sheet metal above the box like on my early 1923 Touring car with low radiator and accompanying low cowl. Other body styles also might be a tight fit from the ends. The kit was made with all those extra clearances and bevels and brace slots. There are also extra grooves underneath the false bottom to allow this same kit to be used from late 1913 through 1925. Be careful what material you use since I have to laugh watching "knock off" kits made by MTBC sources using plastic that has more carbon in it than wood has.
I just installed John Regan's waterproof kit in my 27. I had a few questions about my coils not fitting in, the coils were about 3/16 to wide. I emailed John and he walked me through it. The coils I was trying to put in were swollen !! The reason why I'm putting in my 2 cents in ,is that John answered my question promptly and I trust all of his products. So like other people are saying buy John's kit it would be much easier.
I respect people who stand behind their products and answers you questions quickly.
I have a sheet of phenolic resin and since it's essentially straight cuts on a table saw ... and drilling a few holes ... I thought it would be fun. Can also use the money for something I can't build. I make gelatin film emulsions from scratch too even though film is still available. Call me crazy. :-)
Hey John Regan,
Maybe we are talking about something different. Sorry, not sure I understand the geometry. How is a slight stepped groove along the entire length of the vertical contact panel grooves going to help inserting the coils from above. I'm thinking they would have actually beveled the bottom of the coils for that.
Do the kit YOUR way without them and put that in a low cowl car where you really can't insert a coil straight down from top to bottom. Next - BEVEL the bottom of the coil enough to let tar leak out when the coil gets hot and finally FORCE it in from the end with a minimum tilt and get it all good and stuck - then decide if you need the clearance or not - perhaps you won't.
I think my last post came off more sarcastic then I meant for it to. Upon rereading it I think I was not very nice and I apologize. To answer your question further the second groove runs the entire length because in mass production both grooves would have been cut with a single cutter most likely so the shallow groove would have been made at the same time the deep one next to it was cut. That means to get the regular groove cut from top to bottom you have no choice but to also cut the one next to it the same length. You yourself of course will cut them separately but the coil unit will be slanted at an angle when you insert it into a low cowl car and the lower coil contact and then upper contact will not be on the center line of the deeper groove but will be over in the area next to the deeper groove. It will tilt up straight once you get it inserted far enough. You may notice that early coil box back wood was cut with straight deep single grooves because indeed on those coil boxes the coils can slide straight down in.
No it was just sarcastic enough. :-) But seriously I was asking because I wanted to have a better understanding of the function of those outer recesses. I was wondering why not simply cut the outer most recesses (for coil 1&4) a little wider at the same depth ... rather than stepped with that second pass of the cutter.
In my day job I teach people very complex techniques of making and using 19th century photographic processes. The trick in teaching technology is being succinct, descriptive and patient when people have trouble with a concept. I respect your depth of knowledge in coil lore.
Ford didn't cut deep recess wider since that groove prevents the coil box contact from rotating. They did NOT cut the shallower groove with a second pass. You are assuming it was cut with a router and it was not. Those deeper grooves and the shallower one next to it were cut via a stacked dado blade on a gang saw. On some of the wood box parts that have survived from original you can see the cross grain marks of the cross cut blades. They were not router cuts. There are some books that explain in great detail many of FORD SHOPS and METHODS. Not sure of the book exact naming. Sometimes pictures from that have been posted on this forum for various operations. I don't have those books but some folks collect them.