During this build of the 1:8 scale Back to the Future DeLorean partwork, we will use more than thirty different kinds of screws. They vary in types and sizes, but are all Phillips-head and appear to be metric. Each screw is designated with a two letter code, such as AP, BP, AM, CM, etc. The first letter indicates the type/size of screw and the second letter indicates which material that screw is driven into:
- P = Plastic
- M = Metal
Before I started my model build, I heard that a few of these screws can be difficult to install (specifically some of the metal screws). I figured that I would need to purchase a metric tap set in case I needed to add threads to some of the holes. However, to use a tap set effectively, I needed to know the screw diameter and thread pitch of every single screw.
Using a set of precision calipers and a thread pitch gauge, I measured all of the screws I have encountered so far. It turns out that most of the screws are not standard metric sizes, so a tap set would be pretty much useless. This means the best way I’ve found to pre-thread a hole is to use the appropriate screw, drive it in, and back it out, before attaching the part.
I thought the information I collected was still useful, so I created this page to share it. The tables below contain all of the screw measurements I have collected so far in my build. I also included the screwdriver bit sizes I found to work best for each screw (the build only supplies #0 and #000 screwdrivers, which it turns out, are not ideal).
Please note that these values are based on my own observations, so they may not be perfect (use at your own risk).
Screw Sizes - Plastic (in mm)
| Name | Screwdriver Bit Size | Head Type | Head Diameter | Head Height | Thread Diameter | Thread Length | Thread Pitch | |
|---|---|---|---|---|---|---|---|---|
| AP |  | #1 | Pan | 3.00 | 1.00 | 1.75 | 4.0 | 0.7 |
| BP |  | #1 | Pan | 3.50 | 1.30 | 2.30 | 4.0 | 1.0 |
| CP |  | #00 | Pan | 2.00 | 0.75 | 1.25 | 3.0 | 0.5 |
| DP |  | #1 | Flange | 4.50 | 1.00 | 1.75 | 2.5 | 0.7 |
| EP |  | #1 | Pan | 3.00 | 1.00 | 2.00 | 4.5 | 0.8 |
| FP |  | #1 | Pan | 3.50 | 1.25 | 2.30 | 4.5 | 0.9 |
| GP |  | #1 | Pan | 3.00 | 1.00 | 2.00 | 4.0 | 0.8 |
| HP |  | #1 | Flange | 5.80 | 1.25 | 2.40 | 4.0 | 0.9 |
| IP |  | #1 | Pan | 3.00 | 1.00 | 1.75 | 3.0 | 0.7 |
| JP |  | #000 | Flange | 4.20 | 0.80 | 1.45 | 3.0 | 0.5 |
| KP |  | #000 | Countersunk | 2.80 | 0.80 | 1.60 | 3.5 | 0.7 |
| LP |  | #00 | Pan | 3.00 | 1.00 | 1.75 | 5.0 | 0.7 |
| MP |  | #000 | Pan | 2.00 | 0.90 | 1.20 | 3.0 | 0.5 |
| NP |  | #000 | Pan | 2.40 | 0.80 | 1.60 | 3.5 | 0.6 |
| OP |  | #000 | Pan | 2.00 | 0.70 | 1.20 | 4.0 | 0.5 |
| PP |  | #000 | Pan | 2.40 | 0.80 | 1.60 | 2.0 | 0.7 |
| QP |  | #000 | Pan | 2.00 | 0.80 | 1.05 | 3.0 | 0.7 |
| RP |  | #1 | Pan | 3.00 | 1.05 | 1.70 | 7.0 | 0.5 |
Screw Sizes - Metal (in mm)
| Name | Screwdriver Bit Size | Head Type | Head Diameter | Head Height | Thread Diameter | Thread Length | Thread Pitch | |
|---|---|---|---|---|---|---|---|---|
| AM |  | #1 | Pan | 3.0 | 1.0 | 1.7 | 3.5 | 0.4 |
| BM |  | #1 | Pan | 3.0 | 1.0 | 2.0 | 5.0 | 0.4 |
| CM |  | #1 | Pan | 3.25 | 1.0 | 2.0 | 8.0 | 0.4 |
| DM |  | #1 | Pan | 3.75 | 1.5 | 2.3 | 4.5 | 0.4 |
| EM |  | #1 | Flange | 6.5 | 1.5 | 2.3 | 4.0 | 0.4 |
| FM |  | #0 | Flange | 5.5 | 1.0 | 2.0 | 4.0 | 0.4 |
| GM |  | #1 | Flange | 5.5 | 1.5 | 2.3 | 4.0 | 0.4 |
| HM |  | #1 | Pan | 3.75 | 1.5 | 2.3 | 9.5 | 0.4 |
| IM |  | #1 | Pan | 3.5 | 1.25 | 2.3 | 18.5 | 0.4 |
| JM |  | #1 | Pan | 3.75 | 1.25 | 2.3 | 4.0 | 0.4 |
| KM |  | #000 | Pan | 3.0 | 1.0 | 1.7 | 3.0 | 0.4 |
| LM |  | #000 | Pan | 3.1 | 1.0 | 2.0 | 7.0 | 0.4 |
| MM |  | #000 | Pan | 2.5 | 0.75 | 1.5 | 4.0 | 0.4 |
| NM |  | #1 | Pan | 3.1 | 1.0 | 2.0 | 4.0 | 0.4 |
| OM |  | #1 | Pan | 4.1 | 1.4 | 2.6 | 5.0 | 0.4 |
| PM |  | #000 | Flange | 4.5 | 1.0 | 1.5 | 2.5 | 0.4 |
| QM |  | #000 | Pan | 2.4 | 0.75 | 1.5 | 3.5 | 0.4 |
| RM |  | #1 | Pan | 4.6 | 1.6 | 2.9 | 6.0 | 0.4 |
| SM |  | #00 | Pan | 3.0 | 1.0 | 1.7 | 5.0 | 0.4 |
| TM |  | #1 | Flange | 6.3 | 1.25 | 2.3 | 5.0 | 0.4 |