# Automatic center punch



## Makintrax73 (Aug 18, 2022)

As a beginner this project was a real skills stretching experience.  My first single point threading on a project, internal too.  I had to make the trigger 4 times, the hammer 4 times too.  So far it seems to work.  Not sure if my hardening job will hold.  







Sure wish I was better at knurling.  Probably should have left that off and did half a dozen practice knurls first.


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## SLK001 (Aug 18, 2022)

It doesn't look like your knurling tool was exactly perpendicular to the surface - one side was more dominant (pressing more) - and not deep enough.  Knurl the raw stock first, THEN turn it to size and your knurls will be more proud of the surface.  Your threading looks excellent as does the fit.  Chuck up your point on the lathe and use some emery paper to remove the discolorization of the metal (unless you like the colored look).

An overall good job.


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## brino (Aug 18, 2022)

Great looking results @Makintrax73 !
Congratulations.

There's no better way to learn than to jump in and build a project.
All your new skills will be very valuable on the next project.

I am a big supporter of doing "practice parts"  to figure out what the machines (and my own) limits are, order of operations, etc.

Well Done!
Brian


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## Just for fun (Aug 18, 2022)

Looks great! 

How in the world did you single point those internal threads?


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## tjb (Aug 18, 2022)

Makintrax73 said:


> As a beginner


That's very impressive for 'beginner' level work.  Beautiful.


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## rwm (Aug 18, 2022)

That is awesome. I am trying to figure out why I have not made one?


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## Makintrax73 (Aug 18, 2022)

Just for fun said:


> Looks great!
> 
> How in the world did you single point those internal threads?



In actual fact I tapped the first hole and got very frustrated with my cheap taps.  On the 2nd I decided I had little to lose and single pointed it. I used an accusize internal threading tool.  Bored the hole quite a bit deeper than required.  Set up a dial indicator and killed the half nut at as near the same depth each pass as possible.....




The sharpie mark is a "back up failsafe"


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## 7milesup (Aug 18, 2022)

That is really awesome!  It looks really nice.


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## rwm (Aug 18, 2022)

Perhaps project 2 should be a good knurling tool?








						Knurling tool build
					

I have a poor quality pinch type knurling tool that so far has not done well. I believe the machine that cut the arms was out of tram and the arms are crooked. After looking at prices I decided to make my own. I am thinking about something like this:    To get started I bought these:      My...




					www.hobby-machinist.com


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## pontiac428 (Aug 18, 2022)

Here, the first 20 pages of the Dorian knurling catalog are instructional details, tables, and equations for perfect knurls of all types.  There is a method to it, believe it or not.  Attached below.


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## rwm (Aug 18, 2022)

pontiac428 said:


> There is a method to it, believe it or not.


The method is witchcraft...


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## benmychree (Aug 18, 2022)

As to the knurling, one hand of the knurl being more/less deep than the other may be caused by the holder set too high or low, double tracking is usually caused by having an odd diameter of the blank, the usual diametral pitch knurls are best for nominal diameters, circular pitch knurls are best for odd diameters., although it would not help in this situation, I like to apply a lot of pressure initially, using only part of the width of the knurl, to establish full tracking of the knurl pattern, then ease off on the pressure and continue across the area to be knurled, making multiple passes if necessary; in production, knurls are made in a single passes after the tool is adjusted to the desired depth.


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## Tipton1965 (Aug 21, 2022)

Looks really good to me.  Great job!


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## Ben17484 (Aug 21, 2022)

Very nice  

I’ll add this to my list of projects to try (I’m also a newbie)


Sent from my iPhone using Tapatalk


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## Just for fun (Aug 21, 2022)

Makintrax73 said:


> As a beginner this project was a real skills stretching experience.  My first single point threading on a project, internal too.  I had to make the trigger 4 times, the hammer 4 times too.  So far it seems to work.  Not sure if my hardening job will hold.
> 
> View attachment 417524
> 
> ...



Beautiful Job!   Are there plans available to make something like that?


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## Makintrax73 (Aug 22, 2022)

Just for fun said:


> Beautiful Job!   Are there plans available to make something like that?



Thanks!  No plans that I'm aware of. 

There are a couple of YouTube videos showing how to make one, along with some information on a Wikipedia page that is helpful.









						Automatic center punch - Wikipedia
					






					en.m.wikipedia.org
				




Basically it was taking a basic design and trying multiple times to get the parts right.


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## SLK001 (Aug 23, 2022)

Makintrax73 said:


> ... and trying multiple times to get the parts right.



Never, never admit to that!


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## Just for fun (Aug 23, 2022)

Thanks for the info. 

I did see there were a couple YouTube's, I haven't checked them out yet.


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