Self tapping screws for the Transfer Case skid plate

Rich K. · Post by **Rich K.** » Wed Jan 07, 2009 3:13 pm

Before I go play "lets see if this one works"

I thought I'd ask if anyone knows what size self tapping screw I need to mount the Transfer Case skid plate. My local "salvage yards" are picked clean for parts.

Thanks for any help.

Post by **HenryJ** » Wed Jan 07, 2009 7:05 pm

It is a metric thread. my guess would be 10mm x 1.25 pitch.

Rich K. · Post by **Rich K.** » Thu Jan 08, 2009 4:35 pm

HenryJ wrote:It is a metric thread. my guess would be 10mm x 1.25 pitch.

Thanks. What ever happened to the day when I could just take my SAE set out to work on my American made vehicle?

I took one off of a friends Blazer and it was a 15mm but the brace was threaded so the bolts were not self tapping. Still working on the guess.

Post by **HenryJ** » Thu Jan 08, 2009 5:23 pm

The head is 15mm and the wrench used is 15mm, but bolts are measured by the diameter of the threaded portion. That is close to 10mm as my guess.

roadrunner · Post by **roadrunner** » Thu Jan 08, 2009 6:25 pm

Rich, I'd crawl under my CC and check but with my messed up back right now I don't want to risk it. It's been too long since I bought my bolts from LMC so I don't remember the sizes.
They are listed on pg 38 &39 (LMC) as pn-31-0205 for $2.95 each with 3 required for the rear of the skid plate. The front two mount bolts are the existing rear mount bolts. I know this doesn't help much but if you can't find them at least they are available there. As I recall they are a tapered self-tapping pointed end bolt without any cutting slot. The pointed end self-starts and they are hard enough to make their own threads.

Rich K. · Post by **Rich K.** » Fri Jan 09, 2009 1:16 pm

Thanks for the thought Larry! Sorry to hear your back is still giving you trouble.

I still have you on our list for prayers.

I'm the electronics guy in a shop of mechanics. I should have known better about the 10mm sizing. Sorry.

I bought the brackets from LMC Truck on page 38 and thought I had the right size self tapping screw here but I was wrong. Do you think the self tapping screw would provide a more secure fit than if I used a tap set and threaded it myself and put in a bolt? They want alround $3.00 a piece for those self tappers at LMC. I know either way I have to be careful to not overtighten them.

roadrunner · Post by **roadrunner** » Fri Jan 09, 2009 3:17 pm

If you go the tap it yourself method I would be sure to put loc-tite on the threads on final assembly. Not the heavy duty locker. Just the blue or red at most.

gocntry · Post by **gocntry** » Fri Jan 09, 2009 3:32 pm

Rich K. wrote:They want alround $3.00 a piece for those self tappers at LMC.

When I Added The Aluminum Shield, I Went To The Local Chevy Dealer, Told Them what I Was After. They Looked Up The Part, Scrounged Around In Back And Handed Me The 3 Bolts At No Charge.

Rich K. · Post by **Rich K.** » Sat Jan 10, 2009 9:31 pm

I wonder if my local dealer would be so generous. I talked to them about the front differential brackets to mount the differential plate and they gave me the deer in the headlight look. They did work with me and we eventually found them. $61.00 for the left and $58.00 for the right. LMC didn't look so bad after that at $17.00 per bracket.

I have a plethera of bolts at my disposal so I think I will try the tap and lock tight. How about this question? Should I use the tap only or put in a Healy coil? Probably the tap first and then the healy coil when I accidentally strip it out

Thanks for the help guys!

Post by **HenryJ** » Sat Jan 10, 2009 10:02 pm

Rich K. wrote:I have a plethera of bolts at my disposal so I think I will try the tap and lock tight. How about this question? Should I use the tap only or put in a Healy coil? Probably the tap first and then the healy coil when I accidentally strip it out

I would stick with the self tapping bolts. the crossmember is not thick or solid. The self tapping bolts tend to push threads in the soft crossmember steel rather than cut threads.
You might be able to tap threads and get that to work, but it will not be a tight pressure fit and you may find the bolts tend to loosen with time.
Heli-coil is not going to be an option. There is just not enough material. They could be drilled and nut-serted if they get stripped.

I measured a spare I have. It is 10mm.

Rich K. · Post by **Rich K.** » Tue Jan 13, 2009 12:50 pm

I would stick with the self tapping bolts. the crossmember is not thick or solid. The self tapping bolts tend to push threads in the soft crossmember steel rather than cut threads.

Thanks! I got my brackets in so I will get these self tappers and install some belly protection.

I measured a spare I have. It is 10mm.

10mm is the diameter of the threads. What is the 1.25? Is that the length of the bolt or something to do with the threads, (course, fine)?

Post by **HenryJ** » Tue Jan 13, 2009 12:55 pm

Rich K. wrote:10mm is the diameter of the threads. What is the 1.25? Is that the length of the bolt or something to do with the threads, (course, fine)?

1.25 is the thread pitch. The metric designation for coarse or fine threads.

Rich K. · Post by **Rich K.** » Tue Jan 20, 2009 7:53 pm

Thank you for the edumacation. I certainly appreciate the time youv'e taken to bring me up to speed.

Rich K. · Post by **Rich K.** » Sun Feb 22, 2009 11:00 pm

I finally got all three plates installed. I found a composite Transfer Case plate at the salvage yard and substituted it for an aluminum plate on a friends Blazer that he is getting rid of.

The 3 transfer case self tapping screws were the 10mm X 1.25. The 4 self tapping screws for the front differential plate are 8mm x 1.25.

S-10CREWCAB.NET

Self tapping screws for the Transfer Case skid plate

Self tapping screws for the Transfer Case skid plate

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