Tapping alone ain't gonna do it.

[SnikPlosskin]

Finally got a 1/8 NPT tap and tried to use it to ream out the brass from the oil sending hole. No go. The brass part in there just is not large enough for the tap to get a hold. I'll have to drill it.

Crap.

I know it requires a #12 bit. Can I use a smaller on to just wear enough brass out to then tap? I'm thinking I can just wobble a smaller bit and cut most of the brass away. I can't see how I could get a #12 bit exactly 90 degrees by hand.

[Sea Six]

I'd tap that.

[SnikPlosskin]

Originally Posted by Sea Six

I'd tap that.

Please do.

[Jeff '79]

Originally Posted by SnakePlissken

Please do.

Don't you have a machinist buddy or a mechanic buddy that could do it for you?
I'd hate to see that pretty thing get FUBAR.

[JRD77VET]

Originally Posted by SnakePlissken

Finally got a 1/8 NPT tap and tried to use it to ream out the brass from the oil sending hole. No go. The brass part in there just is not large enough for the tap to get a hold. I'll have to drill it.

Crap.

I know it requires a #12 bit. Can I use a smaller on to just wear enough brass out to then tap? I'm thinking I can just wobble a smaller bit and cut most of the brass away. I can't see how I could get a #12 bit exactly 90 degrees by hand.

1/8-27 NPT takes a letter "R" drill which is .339 in diameter ( about 1/32 larger than 5/16" ). A #12 drill is .189 ( just bigger than 3/16" )

Yes, in brass you can make a hole bigger. Use a short drill bit and be careful as they are not designed for the side load

edit-- drill size chart
http://www.brokenbolt.com/images/sta...-tap-drill.pdf

[Bill]

You've tried an ease out with no success? Is it possible that it was tapered too much (flared out too much) to get a good bite? What are the possibilities of finding one that is much less tapered, so that you can get the bite lower and over a larger surface area? Also, have you considered just using a slotted or phillps screwdriver, hammering it in until it bites, then trying to twist to loosen it up? I just had to do that with a grease zerk that had broken off in the tail wheel of a mower.

[ZipZap]

11/32 is the SAE bit that I use for 1/8 NPT. Be careful when you tap to not go too far in as the 1/8 NPT is a taper thread.

[JRD77VET]

Originally Posted by ZipZap

11/32 is the SAE bit that I use for 1/8 NPT. Be careful when you tap to not go too far in as the 1/8 NPT is a taper thread.

11/32 is .3437 and close enough. A NPT thread is usually at correct depth about 2/3rds of the way up the tap.

[Blademaker]

Originally Posted by JRD77VET

1/8-27 NPT takes a letter "R" drill which is .339 in diameter ( about 1/32 larger than 5/16" ). A #12 drill is .189 ( just bigger than 3/16" )

Yes, in brass you can make a hole bigger. Use a short drill bit and be careful as they are not designed for the side load

edit-- drill size chart
http://www.brokenbolt.com/images/sta...-tap-drill.pdf

Originally Posted by JRD77VET

11/32 is .3437 and close enough. A NPT thread is usually at correct depth about 2/3rds of the way up the tap.

I'd listen to the precision machinist if I were you........

[Kerrmudgeon]

They do make 90 degree attachments for your drill or dremmel to drill in tight spaces.

[SnikPlosskin]

Originally Posted by bill_daniels

You've tried an ease out with no success? Is it possible that it was tapered too much (flared out too much) to get a good bite? What are the possibilities of finding one that is much less tapered, so that you can get the bite lower and over a larger surface area? Also, have you considered just using a slotted or phillps screwdriver, hammering it in until it bites, then trying to twist to loosen it up? I just had to do that with a grease zerk that had broken off in the tail wheel of a mower.

I tried a screw remover. The kind that is reverse threaded. Really cranked it in there but it would just not move. It did pulverize the brass and some brass came out on the threads of the tool.

It's hard to take it to a machinist because it can't be driven. I think drilling it out is the answer. What a pain in the ass.

If I can remove enough brass to get the tap started it should cut right through. Brass is so much softer than cast iron. With my luck, I'll be pulling the damn motor...

[Bill]

Originally Posted by SnakePlissken

I tried a screw remover. The kind that is reverse threaded. Really cranked it in there but it would just not move. It did pulverize the brass and some brass came out on the threads of the tool.

It's hard to take it to a machinist because it can't be driven. I think drilling it out is the answer. What a pain in the ass.

If I can remove enough brass to get the tap started it should cut right through. Brass is so much softer than cast iron. With my luck, I'll be pulling the damn motor...

Were you using a drill? Maybe try one more time, but hammer in the ease out, then use an open end wrench (2 end to end, actually) and try to spin it by hand. If you are using a drill, you may not be getting the bite you need because it is sleeping.

[SnikPlosskin]

Whew. She is back on the road.

Ended up using a 5/16 bit and carefully removing just enough material to get the tap seated. Then I tapped it, removed, cleaned the debris and repeated. Finally the last small ring of brass came loose and I retrieved it with a bent pin.

Ended up removing throttle linkage, coil, distributor cap and wires.

Taped a soda straw onto a shop vac and sucked out the grease and brass shavings.

Covered up the carb and bare distributor and turned the motor over to blow out any remaining debris. (yes, it made a huge mess.)

Installed new sending unit, reassembled and fired it up. No leaks.

Now I need to clean up the oil on the floor and change the oil in the car. Off to Walmart to get Mobil1.

What a PITA. Thanks to all for your advice.

[JRD77VET]

Good to hear you got it

[SnikPlosskin]

Originally Posted by JRD77VET

Good to hear you got it

I owe you a beer or three. One thing that bugs me is my ceramic coated headers are now stained with baked on oil. I think I can get up under there and hit it with lacquer thinner.

Stupid, I know but I paid good money for those shiny headers....

[lspencer534]

Uh..."tapping alone". Not what I thought the tread would be about. Sorry for interrupting.

[Kerrmudgeon]

......

Got any pics of that midyear Pete?

[73sbVert]

I think of tapping like:

https://www.youtube.com/watch?v=O2LzL_vPmyg