Can you identify the pressure angle of this gear?

[stioc]

It's a change gear from my 9x20 Grizzly lathe. I'm pretty sure its DP is M1 as it works out to 25.xx. As for the pressure angle I was going to say 20deg without looking at it closely but now I'm leaning towards 14.5deg

 

[Bi11Hudson]

The 9X20 Grizzly lathes are/were G-4000 and G-1550. Spindle thread is biggest visible difference. One made in mainland China, the other in Taiwan. In either case, the gears are 20 deg, modulus 1. I have the 1550 and have used gears from a HF machine. They interacted fine.

Bill Hudson​

 

[stioc]

@Bi11Hudson thanks for confirming that. I was comparing that gear with this silhouette and couldn't quite tell. Now I know which gear cutter set to buy if I decide to make some odd ball change gears for the lathe.

 

[Iceberg86300]

@Bi11Hudson thanks for confirming that. I was comparing that gear with this silhouette and couldn't quite tell. Now I know which gear cutter set to buy if I decide to make some odd ball change gears for the lathe.

Whenever I need to answer this question & the gear has been large enough, I make a rubbing of the gear. Scan it & then import it as a sketch/whatever into the CAD program of your choosing, sketch a few lines over the gear & then measure.

Works pretty well.

Sent from my SM-G900V using Tapatalk

 

[stioc]

^ that's pretty clever! I'll have to try that. Thanks

Another tip I found reading a long thread on the PM forum was that generally the root profile of the 20deg gears is round where as 14.5deg gears is flat.

 

[benmychree]

Nearly all metric gears that one will encounter are 20 deg. pressure angle. If one works with gears often, they should buy a set of templates that come with both pressure angles on each template of a different pitch in all the common pitches. Also stock gear catalogs usually have a page with full size printed representations of all the common pitches.

 

[stioc]

So I tried the scan and import method, I failed. The scan (on my flatbed scanner) comes out as a jpg. Tried converting it to SVG or DXF using online converters and then tried importing it into Fusion 360 but the conversion makes a very crude looking eclipse. Attached is the scanned gear if anyone's curious enough to want to give it a try.

 

[Iceberg86300]

So I tried the scan and import method, I failed. The scan (on my flatbed scanner) comes out as a jpg. Tried converting it to SVG or DXF using online converters and then tried importing it into Fusion 360 but the conversion makes a very crude looking eclipse. Attached is the scanned gear if anyone's curious enough to want to give it a try.

Solidworks has an import photo option. You just place it onto a plane & then start a sketch on the same plane. I just draw some lines & curves (if I'm feeling adventurous) & then measure the angle. I've never actually tried to convert one into geometry.

Is there no similar option in fusion?

Your photo is exactly why I try to make a rubbing first if the gear size allows it.



Regards,

Steve

 

[benmychree]

I used my optical scanner on the picture; it is 20 degree P.A. ---

 

[stioc]

Thanks guys! Now you guys are making me feel dumb, what's a 'rubbing' and what's an 'optical scanner'?

I'm trying to learn the technique for future use so I tried the lines on the jpg and I can make the angle whatever my brain leans towards lol See the two comparisons.