Ok this is probably not something anyone will be able to answer, but I figured I'd give it a shot! Does anyone happen to know what the thread size is for the stock 400ex oil dipstick?

I was thinking about buying one of those XRs Only Temperature Gauge Dipsticks, and $50 for one isn't really that bad, but I got to thinking that I could probably make one for a fraction of the price.

I went down to Harbor Freight and found a nice 6" long digital temperature probe for $5.99 that reads all the way up to 392 degrees F (Instant Read Digital Thermometer).

Now I just need a plastic/nylon bolt or plug (brass would also work, just something easy to drill through) that will screw into the oil tank in place of the stock dipstick, and then drill a small hole through it for this temperature probe to slide through and into the oil tank. The threads look to be about 1/2" in size and really coarse thread, so I tried to find something that would work at my local Lowe's stores, but I couldn't find anything in a 1/2" size that had the same coarse threading.

I'm open to any and all suggestions here. I'm just trying to be creative and see if I can do it while saving some money vs the XRs Only dipstick! I've even thought about using something like a rubber wine bottle cork and trying to screw that into the oil tank threads but I haven't gone that route yet.

I could buy another stock dipstick and try to modify it by removing the metal gauge piece that goes into the tank, and then drilling a hole through it for the temperature probe, but I was hoping to find a better and cheaper alternative since a used stock dipstick runs about $15 on Ebay. I should be able to find a bolt/plug with a hex head that will fit for like $1 SOMEWHERE.

 

It would be extremely helpful if I could get someone who owns a measuring caliper (I don't own one), to please take some measurements of the dipstick threads for me!

I need to know:


1. Major Diameter


2. Pitch/Threads Per Inch


3. Thread Length



I would greatly appreciate it!!

 

Well, the dipstick definitely appears to be a non-standard thread... I still haven't been able to actually measure the threads or get someone with a caliper to do it for me, but I went ahead and bought a 1/2" UNC (Unified National Coarse Thread) hex head nylon plug to see if it would work. The 1/2" diameter seems to be right, but even the UNC coarse thread wasn't coarse enough, and I have been unable to find anything else in a 1/2" diameter with a coarser thread.