Tap or chase? Pics inside

[Sdot]

Hi guys

trying to figure out best way around this. Steel material. There are decent amount of threads in tack here so will using a tap cause loose fitting bolt? Or cross threaded mess?
Right now bolt can’t be threaded in by hand. About 1/2 turns and it hangs up on something.

thanks in advance

 

[Bigblue&Goldie]

A tap might work if you can get it in there properly. Taps "cut", therefore they remove material. A thread repair tool re-forms the threads, so in theory they should work better on damaged threads. If you have to buy a tool, I'd say get thread repair tool. If you already have the tap, I'd probably give that a try.

 

[nadogail]

Because there are many variables involved; such as what stress is there on the threaded connection? The thickness of the threaded material? is there a need for the connection to be leak proof? and other considerations that don't immediately come to mind plus I have not seen the problem; I decline to say more than "it depends".

 

[Mechtech]

I would use a thread chaser IF you are 100% sure you have the right bolt thread. 1/2 turns and hang is usually an indication that the pitch on the fasteners are not matched.

 

[PCustoms]

I would use a thread chaser IF you are 100% sure you have the right bolt thread. 1/2 turns and hang is usually an indication that the pitch on the fasteners are not matched.

This.

 

[4 FN 27]

I agree with Chasing the treads not cutting. But you might try a Roll Form Tap if you are worried about cutting and making the thread out of spec. They can be pricey but very effective.

 

[PCustoms]

In a pinch I've ground a slot lengthwise in a bolt and used that as a thread chase. The bolt won't cut new threads, and the slot leaves room for the paint to clear.

I really think you've got the wrong bolt though.

What is this on, and what size bolt are you using?

 

[larry_g]

That also looks like a through hole? Can you thread in the screw from the back side and see if it will go in and hang up at the same spot? Are there other threaded holes in this piece that you can confirm that the screw threads into properly, even if you have to remove another fastener? Have you examined the fastener closely to confirm that it has no damage to it?

lg
no neat sig line

 

[Sdot]

Appreciate the replies guys and to answer a lot of your questions. 110% sure of the bolt size and pitch: m8x1.25. Connection doesn't need to be leak proof and no access from the back side. Hardware that came out was a bit fajunked up also, which I ran through the metric Lang thread chaser set I have (gold bits).

Been trying the Lang thread chaser. But get nervous when it hangs up. Not wanting to push it through the threads (though that's what it needs to do) I have a feeling this is where I need to be really careful if its cross threaded or not. Any way to even determine that? or get through it?

Thanks again

 

[kbeefy]

In a pinch I've ground a slot lengthwise in a bolt and used that as a thread chase. The boots won't cut new threads...

I've been able to cut threads this way in softer metal.

 

[PCustoms]

Appreciate the replies guys and to answer a lot of your questions. 110% sure of the bolt size and pitch: m8x1.25. Connection doesn't need to be leak proof and no access from the back side. Hardware that came out was a bit fajunked up also, which I ran through the metric Lang thread chaser set I have (gold bits).

Been trying the Lang thread chaser. But get nervous when it hangs up. Not wanting to push it through the threads (though that's what it needs to do) I have a feeling this is where I need to be really careful if its cross threaded or not. Any way to even determine that? or get through it?

Thanks again

Ok, what is the part?

Some of those nuts are lobed/pinched or have an interference fit as a self locking feature.

 

[Sdot]

Ok, what is the part?

Some of those nuts are lobed/pinched or have an interference fit as a self locking feature.

okay, after some digging. It’s a “Dog-point” bolt that was removed.
This may help a lot with diagnosing.

also did pick up an Irwin tap - but not jumping there yet

 

[PCustoms]

okay, after some digging. It’s a “Dog-point” bolt that was removed.
This may help a lot with diagnosing.

Not from my perspective....

What the hell is this super top secret bolt application?

 

[htmdude57]

I don't think there is anything special about a dog bolt's threads? Dog bolt is just a bolt with a reduced size tip. I think there are lots of them on cars.

 

[Sdot]

Not top secret location- just not interesting.

got it. Only made mention of them since didn’t know if that effects how you tap or which type tap you could use

 

[joe49]

Drill top 2 threads out that seem to be bad, then chase with a tap.

 

[Jlarson]

If I know the thread is right I'll run the Lang chasers hard. I use em with an electric ratchet a lot on multiple holes a lot, they are pretty tough.

 

[Sdot]

Making some progress here (or so it feels) with the Irwin tap I got today.

only have it in a bout 2-3turns. But it’s getting through some junk with a tight hand turn and then slight turn backwards, repeat.

getting the t-handle on while it’s in the hole is dangerous…and only way I can “feel” is by hand

 

[Sdot]

Deed is done! Thank you everyone for your help.

got the bothered threads corrected with the tap, and rest of threads were all good! Phew! Lucky!
Love this place.

 

[jon72vega]

I'm late to the party as you have your problem threads repaired, but I recently made a thread chaser out of a bolt to get some **** out of some threads.
It worked very well for me.
Cleaning threads by jon72vega, on Flickr
Cleaning threads by jon72vega, on Flickr