Alpha one gen 1 shift cable brass bolt thread

[Jussi-T.]

Hi!

I removed the brass bolt which was stuck and I thought it would be good to fix the threads a little bit with a tap.

Question is:

Which tap I need to buy?

1/4 x 18 NPT or 1/4 x 18 NPS

Thanks!

 

[Eric 3.7LX Alpha 1]

Re: Alpha one gen 1 shift cable brass bolt thread

Are you referring to the threads on the end of the shift cable at the engine? I don't know what thread size they are but I do know they are not NPT.

 

[achris]

Re: Alpha one gen 1 shift cable brass bolt thread

If you are referring to the brass BARREL at the end of the lower shift cable, then it is 'stuck' on purpose. It is suppose to be that way. It is not suppose to be moved... Now your adjustment is out, and you are going to have to go through the complete adjustment procedure....

Chris...

 

[Bt Doctur]

Re: Alpha one gen 1 shift cable brass bolt thread

Thinking you mean the nut you see in the gimbal housing where the shift cable is.1/4 x 18 NPSF

 

[Jussi-T.]

Re: Alpha one gen 1 shift cable brass bolt thread

Bt Doctur: That's exactly what I mean. Sorry my bad, I should have tell more specifically what I meant.

I think this is the tap I need. 1/4 nps taper thread tap--new | eBay

 

[Jussi-T.]

Re: Alpha one gen 1 shift cable brass bolt thread

Sorry, double post.

 

[Bt Doctur]

Re: Alpha one gen 1 shift cable brass bolt thread

No, you need a 1/4 x 18 STRAIGHT TAP Not a tapered one http://www.ebay.com/itm/1-4-18-NPS-...ff-Nestor-R-N-53777-Made-in-USA-/271454205531

 

[Jussi-T.]

Re: Alpha one gen 1 shift cable brass bolt thread

Bt Doctur: Yes I noticed also that that wasn't correct one. The title says NP(S)=straight, but then it is said in the item description TAPER (which should be NPT I think?)

Well I ordered this one: http://www.ebay.com/itm/201050540505?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2648

It should be STRAIGHT not TAPER

Thanks Doctur!!

 

[Jussi-T.]

Re: Alpha one gen 1 shift cable brass bolt thread

NPT / NPS thread taps aren't available here in Finland. Well okay, sure you can get them, but the price is huge due to they are very rare here. UNC/UNF taps are commonly used here or some Whitworth threads.

 

[Bondo]

Re: Alpha one gen 1 shift cable brass bolt thread

NPT / NPS thread taps aren't available here in Finland. Well okay, sure you can get them, but the price is huge due to they are very rare here. UNC/UNF taps are commonly used here or some Whitworth threads.

Ayuh,... Don't feel bad, they're pretty darn rare 'round here too,....

Not common at All,..

 

[Jussi-T.]

Re: Alpha one gen 1 shift cable brass bolt thread

Ok, I see.

Could someone elucidate me a little - what does 1/4 x 18 mean? I know 18 means threads per inch, but 1/4"? The diameter of the tap is more like 1/2" if you ask me... if you measure from peak..

 

[Bondo]

Re: Alpha one gen 1 shift cable brass bolt thread

Ok, I see.

Could someone elucidate me a little - what does 1/4 x 18 mean? I know 18 means threads per inch, but 1/4"? The diameter of the tap is more like 1/2" if you ask me... if you measure from peak..

Ayuh,.... It's the diameter of 1/4" Pipe,...
'n of course the 18 is threads per inch,...

 

[Bt Doctur]

Re: Alpha one gen 1 shift cable brass bolt thread

That's the one you need.
Commonly called 1/4 inch pipe plug tap. This is the same size as the ones on the fuel sep filter housings.They are "tapered " threads.
You could IF YOUR VERY CAREFUL grind off the last few threads of a 1/4 inch pipe plug tap and use that . But if you guess wrong and leave to much thread on the tap you will create a taper thread that will ruin the housing.
The are additional sizes, such as 1/8 inch pipe plug, diameter wise its more like 1/4 inch diameter. commonly found in heat exchangers, exaust manifolds , sometimes engine blocks. Next is the 1/2 inch pipe plugs nornmally the drain plug at the transom. Then 3/4, 1 inch, etc.
Might want to print these for reference
Machinist Pipe Thread Tap - Drill Size Chart ANSI - Engineers Edge
http://http://www.shender4.com/thread_chart.htm
Fractions to Decimals
http://www.heatinghelp.com/images/posts/8340/resize_Pipe Sizing Chart Basic.jpg

 

[Jussi-T.]

Re: Alpha one gen 1 shift cable brass bolt thread

Bt Doctur:
Do you mean I have to grind off threads from this tap I bought? New 1 4" 18 NPS Straight Pipe HSS Tap 1 4 18 TPI | eBay

Or do you mean that if I would use a taper tap like the first one I linked, THEN I would have to grind the last few threads?

 

[Bt Doctur]

Re: Alpha one gen 1 shift cable brass bolt thread

No, the one you ordered is the one you need . In a pinch ,you can remove the last few threads from a !/4 x 18 NPT tapered tap .
I made it years ago before I could get the merc tool.

 

[Jussi-T.]

Re: Alpha one gen 1 shift cable brass bolt thread

Ok, thanks for the tip!

Have been searching for this tap throughout the week, have asked many many local hydraulics shops but none of them had it... So I had to order it all the way from China

It is amazing how cheap it is to order stuff from China, For example this tap cost about 10 USD and free delivery. The taps seemed to be pretty cheap in the states too but shipping is much more expensive... Well, I hope the China quality is good enough in this case

Thanks for help guys!! This forum is THE BEST!!!

 

[achris]

Re: Alpha one gen 1 shift cable brass bolt thread

Be careful with stuff coming out of China. For machine tools, like taps, die-nuts and drill bits, the metals tend to be a bit on the soft side. In this case you'll be ok because you're only using the tap to clean up an existing thread, and it's aluminium... But if you were to try and cut a new thread in a piece of steel, might be a different (sad) story....

Chris.....