Thread cleaning tap--M12 x 1.25 for block

[BigD1]

Need a M12 x 1.25 thread cleaning tap, so I can clean the block head bolt holes on my Toyota pickup . All I can find is ARP 912-0006 thread cleaning tap, and it is ridiculously priced round about $65 to $70. I can find plenty of regular four flute cutting taps, but I don't think I should be using those to clean holes. Don't want to take a chance of messing up a good block. Only option I have right now is to cut slots in a head bolt which I think would work, but it's definitely not ideal. Don't want to be cutting slots on bolt threads, and I might end up with messed up threads. Let me know please what options I have, or where I can get a thread chaser that's reasonably priced. Cleaning tap will have to be long enough to go down in a blind head bolt hole, so a little stubby won't work.

 

[Rand]

From what I can see you have the normal 4 fluted design starting around 8$ or really expensive ones If you are careful I dont think you would have a problem with a normal tap.. once its in a few threads. I have done this many times.. however you must use caution of course. I would get something like this https://www.amazon.com/IRWIN-1842ZR-Tap-...ds=m12+1.25+tap The comments section people are mentioning it worked good on their 22R head.. so I must not be the only one that thinks it is ok to do so.

 

[SZR48207]

Might check if you can rent one from a auto parts store or maybe even a local machine shop. But funny thing about chasing threads... I think it was the practical machinist forum where this question came up and the folks there all agreed that you would just run a cutting tap through the hole. The idea of a tap made specifically for cleaning threads didn't make any sense.

 

[andyd]

If you're worried, buy another M12 bolt and a nut or 2. Dremel, or hack saw the flutes. Use the nuts to clean up the threads after cutting the flutes. The last head I did, I ran a head bolt in and then blew any debris out of the holes. If the bolts came out without drama, they should go back in likewise. I was taught to push the bolts through cardboard in the way they came out, so the bolt goes back where it came from. How are the intake and exhaust manifolds' hardware?

 

[Donald]

You need a bottoming tap not a regular tap.

 

[BigD1]

Originally Posted By: Rand

From what I can see you have the normal 4 fluted design starting around 8$ or really expensive ones If you are careful I dont think you would have a problem with a normal tap.. once its in a few threads. I have done this many times.. however you must use caution of course. I would get something like this https://www.amazon.com/IRWIN-1842ZR-Tap-...ds=m12+1.25+tap The comments section people are mentioning it worked good on their 22R head.. so I must not be the only one that thinks it is ok to do so.

Already had that one in my cart! If I do end up buying a cutting tap, I think I will buy the Kodiak. It states in the description that it is used for 22RE doing rebuilds. https://www.amazon.com/gp/product/B007BTQJEE/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

 

[Linctex]

Why use a tap at all? In aerospace, you just do a "running torque" If the bolt reaches the bottom of the hole without having to apply excessive torque (like, just a couple inch pounds) then leave the threads ALONE. I've seen too many taps take good metal out of holes that were fine if just left alone. The "run of the mill" taps you can buy usually do this. "ridiculously priced round about $65 to $70" You think Toyota made your block threads with an $8 tap?!?!? SHEESH!! You are dangerously close to making a good situation worse if you go by what you "feel" and not by applying GOOD machinist practices!!

 

[Trav]

Just cut a a couple of flutes in the head bolt with a dremel if you really need a chaser, if you need to fix slightly buggered threads cut 3 or 4 in a hardened bolt or buy this, its the same thing but high quality. I much prefer using a bolt than a cutting tap if the threads just need a good cleaning, most of the time I just use a plumbers 1/2" or 3/4 pipe cleaning brush with some liquid wrench on bolts 12mm and up twist it down and rotate it not push pull then wash the hole out with brake fluid and an air blow gun. You can also use a small wire round brush on a dremel and rotate it around on low speed, works fine also. http://www.ebay.com/itm/M12-x-1-25-Spark-Plug-Thread-Forming-Roll-Tap-Cleveland-USA-Harley-Twin-Cam-NOS-/322576544914?hash=item4b1b0f7492:g:emQAAOSwubRXNSpo&vxp=mtr Edit: As posted if the bolt goes in and goes all the way down the threads, clean it with some brake cleaner an be done with it, leave well enough also.

 

[BigD1]

Originally Posted By: andyd

How are the intake and exhaust manifolds' hardware?

The only two local automotive machine shops around here are backed up for about two weeks. Can't let this truck sit this long waiting on head work. Head has about 186,000 miles on it, and it's possible that the head has already been straightened one time or another. I bought a new casting head loaded that will be ready to drop in after I get it apart. I bought an exhaust and intake manifold stud kit from LCE Performance. Mostly use bolts on the intake on stock head, but I am going to install the intake stud kit which will make it easier to hang the manifold plus I won't wear out the threads on the intake side of the head if I have to take it apart again. Doing the whole top end on my 22RE since I am in that far doing a head gasket plus I have slight chain slap at cold startup after it sits all night. It's got 186,000 miles on the engine. Going to install new water pump, fan clutch, oil pump, timing set, timing cover, and new cylinder head bolts.

 

[BigD1]

Originally Posted By: Trav

Just cut a a couple of flutes in the head bolt with a dremel if you really need a chaser, if you need to fix slightly buggered threads cut 3 or 4 in a hardened bolt or buy this, its the same thing but high quality. I much prefer using a bolt than a cutting tap if the threads just need a good cleaning, most of the time I just use a plumbers 1/2" or 3/4 pipe cleaning brush with some liquid wrench on bolts 12mm and up twist it down and rotate it not push pull then wash the hole out with brake fluid and an air blow gun. You can also use a small wire round brush on a dremel and rotate it around on low speed, works fine also. http://www.ebay.com/itm/M12-x-1-25-Spark-Plug-Thread-Forming-Roll-Tap-Cleveland-USA-Harley-Twin-Cam-NOS-/322576544914?hash=item4b1b0f7492:g:emQAAOSwubRXNSpo&vxp=mtr Edit: As posted if the bolt goes in and goes all the way down the threads, clean it with some brake cleaner an be done with it, leave well enough also.

Yes I am going to leave well enough alone! Believe I will be OK using a 1/2 plumbers heavy duty fitting brush with some Liquid Wrench per your suggestion. Will keep it simple and cheap, and it should do a good job. http://www.homedepot.com/p/Oatey-1-2-in-Heavy-Duty-Fitting-Brush-313272/100142649

 

[Trav]

That's the one, it works great, just a couple of turns and your done.

 

[Yah-Tah-Hey]

A M12X1.25 bottoming tap should be all you need.Go very easy and use a cutting oil. And use the smallest wrench you have on the tap. You may be able to find a chasing tap in the required size but I don't think you need it.

 

[scurvy]

It sounds like you're just trying to clean up the threads. Would a back tap work? It's a collapsable thread chasing tap that you insert into the bottom of a tapped hole (where the threads are usually not boogered up), expand the tap to mate with the threads, then turn it backwards to clean out and refine any of the threads that need some improvement. https://smile.amazon.com/Back-Tap-12-Millimeter-Reverse-Re-Thread-Tool/dp/B000NOX3KW ?

 

[Merkava_4]

Why not a re-threading tap if all you're doing is cleaning threads ? https://store.snapon.com/Rethreading-Tap...t--P651935.aspx

 

[BigD1]

Originally Posted By: scurvy

It sounds like you're just trying to clean up the threads. Would a back tap work? It's a collapsable thread chasing tap that you insert into the bottom of a tapped hole (where the threads are usually not boogered up), expand the tap to mate with the threads, then turn it backwards to clean out and refine any of the threads that need some improvement. https://smile.amazon.com/Back-Tap-12-Millimeter-Reverse-Re-Thread-Tool/dp/B000NOX3KW ?

Not sure about that type because I have never used one.

 

[BigD1]

Originally Posted By: Merkava_4

Why not a re-threading tap if all you're doing is cleaning threads ? https://store.snapon.com/Rethreading-Tap...t--P651935.aspx

I saw those, but I think it might be too short. They don't list the length. Going to try and clean them up with a plumbers brush, and then see how the new head bolts work with the holes. If there is too much resistance after cleaning, I found a shop that will make a thread chaser for me with t-handle welded onto it. It will look this one on Ebay. https://goo.gl/q2V9Mf

 

[Merkava_4]

Originally Posted By: BigD1

I saw those, but I think it might be too short. They don't list the length.

Use a regular cutting tap then. If the H-limit of the tap you're chasing with is the same as the H-limit of the tap the factory used, you shouldn't get any metal chips. The most common H-limit is H2. The purpose of chasing threads for head bolts in so you get an accurate torque. I'd start out with a taper tap first before I ran a bottoming tap through there.

 

[scurvy]

Originally Posted By: BigD1

Not sure about that type because I have never used one.

If you are attempting to do this:

Originally Posted By: BigD1

clean the block head bolt holes on my Toyota pickup

and some of the threads are boogered up at the top of the threaded hole (but the threads at the bottom of the hole are in good shape) then a back tap is exactly the tool you need. If the threads are in good shape but have dirt/rust/grease/pookie in them, you need small round brushes and solvent.

 

[Trav]

Originally Posted By: BigD1

Originally Posted By: Merkava_4

Why not a re-threading tap if all you're doing is cleaning threads ? https://store.snapon.com/Rethreading-Tap...t--P651935.aspx

I saw those, but I think it might be too short. They don't list the length. Going to try and clean them up with a plumbers brush, and then see how the new head bolts work with the holes. If there is too much resistance after cleaning, I found a shop that will make a thread chaser for me with t-handle welded onto it. It will look this one on Ebay. https://goo.gl/q2V9Mf

Those are really not much different than a fluted bolt which is preferable to a cutting tap. The problem with using a cutting tap is you don't know what class the fit originally was cut to and that's important with something like head and main saddle bolts, crank bolts, etc. I have taps here that use 3 different taps for one size to produce a close tolerance fit, they are used in 3 steps. Go and stick a sloppy 1B tap in the hole and you just buggered the 3B threads badly enough they cannot be restored to their original tolerance, now you have a real problem not just a dirty threaded bolt hole. Most stuff on a car engine is 2B internal, you can tell the fit is not close tolerence because it has plenty of wiggle. Its always best check the fit class and use the correct tap(s) if that's what really needs to be used. A fluted original bolt fits the cut threads perfectly regardless of fit class, it will start easily because it maintains the original chamfer and because its flutes will reform slightly buggered threads with minimal cutting action or damage Tap Info http://www.newmantools.com/taps/taptech.htm

 

[SHOZ]

Be sure to use a tap wrench too, not an open end one.