Tap drill size for 1/2 -10 Acme

[Stephen S]

Here is some info that puts it at .405. Mike


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Tap drill size for acme taps​

this page is for information only​

link to Acme Tap page

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tap drill size for acme taps

Based on a 100% of thread as per ANSI
to calculate tap drill size for acme taps.

the magic formula
step 1
1 Divided by TPI ( threads per inch)
step 2
subtract this amount from the OD.
for pitches 10 and greater always add .005" for the drill size.
for pitches less than 10 TPI take the amount from step 1 and multiply x.05 ( 5 %) and add this to the drill size.
This is for 95% to 100% threads.

---

eg 1/2-10
1/10 = .100 ( step 1 )
.500 ( the OD ) minus .100 ( from step 1) = .400 drill size.
since the pitch is 10 or greater add .005" so the drill size is .405"

---

eg 3/4-6

1/6= .167"
.750 - .167 = .583" ( 100% )
.167 X .05 = .008" ( to obtain 5% )
.583 + .008 = .591" ( 95%)

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Great information, Thanks
I am new here. I am going to make a new nut for my Clausing 6339 compound slide. I have 0.015" play. I just replaced the cross-slide nut went from 0.045" to 0.004" in the loses spot. (I purchased the cross-slide nut on eBay. This is with the original lead screw. When i back out it gets very tight 1/2" before it would go all the way back.
I copied it and put it in a folder for future reference.

 

[RaisedByWolves]

It would seem like if .400 is the size then finding one should be no problem right?

Perhaps. The tap I have coming is a tandem tap which is a new thing for me. Seems as though it taps in two stages, a rough and a finish.

I’m currently making the same vise with the same type of tap, and boy are you in for a fun time.

The first stage is a biotch to get through, the second is a bit easier. Use some EP type of cutting fluid and learn to feel when the tap is flexing.

Been doing this sort of thing for over 3 decade’s professional and this operation gave me pause.

What material? Mine was in A2.

ETA: I only just now realized I replied to something on page one of a nine page thread.

Oops!

 

[DavidR8]

I’m currently making the same vise with the same type of tap, and boy are you in for a fun time.

The first stage is a biotch to get through, the second is a bit easier. Use some EP type of cutting fluid and learn to feel when the tap is flexing.

Been doing this sort of thing for over 3 decade’s professional and this operation gave me pause.

What material? Mine was in A2.

ETA: I only just now realized I replied to something on page one of a nine page thread.

Oops!

I never ended up building it but I still have all the stock to make it.
It is just 1018 cold rolled stock that I have.

 

[wachuko]

I want to make another one using an ACME thread rod... The revival of this thread was perfect!

Let me order the tap from McMasters..

Acme Thread Tap - Right Hand, 1/2"-10 Thread Size, 2-9/16" Thread Length

Dropbox

www.dropbox.com

 

[RaisedByWolves]

I never ended up building it but I still have all the stock to make it.
It is just 1018 cold rolled stock that I have.

Funny, my project has been stalled now for a while too.

I want to make another one using an ACME thread rod... The revival of this thread was perfect!

Let me order the tap from McMasters..

Acme Thread Tap - Right Hand, 1/2"-10 Thread Size, 2-9/16" Thread Length

View attachment 476497

Dropbox

www.dropbox.com

OOF, $113? You need engineering to order you that.



.

 

[DavidR8]

Funny, my project has been stalled now for a while too.
.

I did buy one off eBay for $80 so <shrug/>

 

[wachuko]

I did buy one off eBay for $80 so <shrug/>

I have a few questions:

Did you share photos in the What Did You Buy Today? thread? No? Come on man! Show some photos!

Did you get a "BTW You Suck" recognition? No? Here you go:

 

[wachuko]

...OOF, $113? You need engineering to order you that.

Nope. What I need is a way to hide the purchase from my wife... I mean, the CFO. Everything is in the cart... along with a few other things I have been meaning to buy... The other things have been there for over a month now.



Maybe next month I will build the courage to place the order...

 

[DavidR8]

I have a few questions:

Did you share photos in the What Did You Buy Today? thread? No? Come on man! Show some photos!

Did you get a "BTW You Suck" recognition? No? Here you go:

What Did You Buy Today?

A new hot water heater . :mad::cussing: Don't you mean a cold water heater? If it's already hot, why heat it? :rolleyes:

www.hobby-machinist.com

 

[wachuko]

What Did You Buy Today?

A new hot water heater . :mad::cussing: Don't you mean a cold water heater? If it's already hot, why heat it? :rolleyes:

www.hobby-machinist.com

Not only are they hard to find, when you do, they are expensive. That was a great find at a great price. Good for you!