3/4 20tpi nuts

[mike4]

Has anyone come across a source of 3/4" 20 tpi nuts?
I have a small shaft which is in a machine , it is held in place by a nut which is dual purpose , 1 to hold the shaft in and 2 to put some preload on a couple of tapered roller bearings .
I dont want to make another shaft as it is not damaged , just some foole has hacked at the nut with a chisel to tighten it , ( normally a thin walled socket is used ", but somewhere during the life of this tractor someone had a BUBBA moment or two.

Now I have to find and repair all of the previous acts of butchery and repair the original faults along with the results of the butchering .

Michael

[lakeside53]

McMaster has them in stainless for about $18 each

http://www.mcmaster.com/#95621A800

For that price (plus shipping) I'd make one (no matter how long it took).

[mike4]

I have looked for a small boring bar setup to make one and if I bought the tooling to make the nut it would be a lot more . Does McMaster sell in small quantities ?
Another alternative if I want to torture myself is to buy a couple of Chinese made taps and try to thread a piece of mild steel , might take a while if I can believe all the naysayers about Chinese tooling.

I havent tried their taps or drills yet and this might be a good time .
Michael

[oldtiffie]

McMaster has them in stainless for about $18 each

http://www.mcmaster.com/#95621A800

For that price (plus shipping) I'd make one (no matter how long it took).

I am pretty certain that McMaster-Carr will not sell to Australia or a lot of other countries external to the USA.

[oldtiffie]

I have looked for a small boring bar setup to make one and if I bought the tooling to make the nut it would be a lot more . Does McMaster sell in small quantities ?
Another alternative if I want to torture myself is to buy a couple of Chinese made taps and try to thread a piece of mild steel , might take a while if I can believe all the naysayers about Chinese tooling.

I havent tried their taps or drills yet and this might be a good time .
Michael

I have quite a few of them and they are very good - perhaps it seems to be a case of where you buy them and what you pay for them.

3/4-20 is a very odd size - why not make a tap from silver steel (ie O1 in the USA)?

[mike4]

Thanks for the replies , I have ordered two taps from a chinese supplier and am very interested in how they perform , as there have been a lot of derogatory remarks posted on a lot of sites .

I also found a supplier in England who will ship to Australia in one off quantities . I didnt wat to replace the shaft as when I got a service manual that thread is used for a specific reason , adjustment of preload is easier than with the more common 3/4" 16tpi .
So now I have a nut and two taps on the way .
Internet search pays off again and this forum is also very helpful..
Michael

[bob ward]

I've found this DIY tool to be useful for small size odd-bod internal threading jobs.

http://madmodder.net/index.php/topic,3523.msg42239.html#msg42239

[John Stevenson]

At 3/4" it's one of the British standard cycle range, normally BSC is 26 all thru but the larger sizes can be 24 or 20.
I have bought some Trapezoidal taps from China, only place i can find the size and pitch and they have been good but they were about £30 to £40 a pop, not cheap 3 for a pound rubbish.

[Mcgyver]

unless you need to make a bunch, why not just single point it? 3/4 is large in that there is tons of room to get in there....grind up a bit of hss and away you go.

[duckman]

Go to any Chevrolet dealer and ask for an axle nut off of a Corvette rear axle, they are 3/4-20 I made some axle drivers for a friend so I have a set of taps.

[lakeside53]

I am pretty certain that McMaster-Carr will not sell to Australia or a lot of other countries external to the USA.

But there's a bunch of forum member that would do that for Mike!

[firbikrhd1]

+1 on Mcgyver's post, just grind up an internal threading tool from HSS. duckman's solution might be the easiest if you have a Chevy dealer nearby. Were it me, I'd make one just for the challenge and experience, but I enjoy a challenge and the pleasure I get from successes, even small ones. In fact, I've been known to spend $5 to make something I could buy for $6. Crazy? Maybe.

[wtrueman]

Duckman: This IS what a forum like this is SO useful for!! Wayne.

[wbleeker]

I have bought spiral point taps from CTC tools in Hong Kong Mike and I did a tapping job the other day with them where I tapped 100, 8mm holes and 100, 6mm holes with no problems. I am waiting on fine 10 and 12mm taps from China so I will see what happens when they get here.
Will

[mike4]

I have bought er collets from CTC and they are not giving any problems .
I dont have any bias for or against any country of origin.
The only thing is that equipment that is offered for a purpose is fit for that purpose .

I dont look for the cheapest , I look for quality and China can and does produce that if you are prepared to pay for it.

I am currently waiting for a nut from an English supplier as there is a time frame for the repairs.
The taps will be used to make spare locknuts for the same customer as a modification.

Michael