Skid Plate Bolts Stripped, Oversize Tap and Drill Bit?

I took my runner to a local shop for a service. Yes, they stripped 3 of 4 skid plate bolts. What size is the next bolt size larger? And what drill bit and tap will I need? New bolts don't thread in the stripped holes so I ran a tap through and it's ok for now. I am expecting the damaged threads to strip in the future so I want the next size up ready to go. So, what will I need to go one size larger? How long do the bolts need to be?

Thank you!

 

Take one out and head on down to your local Ace Hardware. They'll set you up.

 

You might want to consider a thread insert as an option, too. Heli-coil type inserts are stainless steel and should help with future potential corrosion and seizing issues. Plus is that you keep the stock size hardware.

 

Funny this comes up, went to replace my stock skid with an RCI and the whole right side bolts were broke off. Now I had to buy a reverse bit set an attempt to un-F**k myself

 

Sucks man.......... a good left handed drill bit set may be your best friend. A good set of spiral extractors might be good to pickup while you're out! They work great if the LH bits don't do the trick for you. Hopefully your frame threads are ok.............

 

Formula for tap drill sizes when you don’t have a chart handy.
What ever the pitch is subtract it from the major diameter = tap drill size.
In your case enlarging the M8 x 1.25 to
M10 x 1.5 you subtract 1.5 from 10 = 8.5mm tap drill size.
For SAE threads it is kinda the same.
Example: 3/8-16
Take the 16 and make it a fraction. 1/16th.
Subtract 1/16” from 3/8” major diameter = 5/16” tap drill size.

 

Thank you!

 

I love all these little nuggets of knowledge I run into when reading these threads. I’ll never remember them when I need them, but I love ‘em anyway.

 

I worked at a National Defense laboratory in a field support unit for a few years. Sometimes we would get called in to a secure area to put out a ‘fire’ and cell phones were restricted. I never knew exactly what needed to be done until we got in there and had no way of getting info off the web and it was a hassle to go back out/in again. I employed every trick I could. Even with my old dried out brain I manage to remember some of them.

 

Count on the weld nuts on the frame to break eventually. Just open the holes up with a 7/16" drill bit and install M8 rivnuts:

$10 30pcs M8 Rivet Nuts Stainless Steel Threaded Insert Nutsert Rivnuts M8-1.25 Threads Nuts

https://www.amazon.com/Stainless-Threaded-Insert-Nutsert-Rivnuts/dp/B07DK8JM6J/

 

Well, time to watch Utube
Never had to use LH bits or extractor before. Wish me luck?

 

If you can, use a center punch and put a divot in CENTER as best you can, take your time.
Start with the smallest bit and get it in the CENTER as best you can. Put the bit deep into the drill chuck so there is less flopping around when you put pressure on it.
Then follow up with a larger bit, sometimes the larger bit will grab in the smaller hole and break loose the bolt.
Use the largest extractor possible and try to put as little of a side load on it as possible.
The extractors are very hard and brittle and if you break it off in the hole you will have a real problem…..ask me how I know…
Myself, I really don’t like extractors, LH bits yes.
I am fortunate to have a mig welder and I place a nut over the remains of the broken bolt and weld through the nut hole and onto the nut.
This gives you something to turn with and the heat from welding seems to help loosen the broken bolt, especially if corrosion is involved.
If the bolt hole isn’t corroded the LH bits wil probably get it out without rolling the dice with an extractor.
Remember….CENTER !

 

Copy that…
Thanks for the assist
Will get around to it prob next weekend. I’ll Post some pics if I remember. But yes… it’s from corrosion. Never had to deal with the shit living in San Diego for 37yrs

 

You're the guy we all want with us on the trail when something breaks!

 

SUCCESS… well 2 of the 3 are done on right side… ran out of time, lady was on my ASS. So it’s pretty secure now. Thanks Again dude!

 

Great job! Really glad it is working.
Being married isn’t for the timid…….

 

Next size SAE will work sometimes