Ok, I give up. 7 start thread

[pdentrem]

I still have the 9 start gear in steel. Went looking for it out in the shed. Pierre

 

[JimDawson]

Yes closer than I've been in over a month of playing width it. Very elusive to say the least. I'm surprised that Jim can get so close using fusion and I'm not even in the ballpark with mastercam. But in mastercam's defense, I'm sure it's operator error with it more than anything.

Figuring out the formula like you did is great. I've read so many how to's on multi start it made my head spin.

I just kept playing with it until I figured it out. I've never tried to do a multi start thread before. I was just using the results you got to get an idea of what was needed given the information we had to work with. We knew the diameter and the crest spacing, so it was just a matter of figuring out how to use the information we had.

I don't have a comparator. I didn't even realize they hand hand held ones. I'm more than willing to buy one. So the hand held ones are really just a magnifier and you compare the part to a scale to get the dimensions?

Yup. I think the one I have is something like this.

Fowler 52-664-009 Pocket Optical Comparators, 10X Magnification: Optical Inspection Apparatus: Amazon.com: Industrial & Scientific

Fowler 52-664-009 Pocket Optical Comparators, 10X Magnification: Optical Inspection Apparatus: Amazon.com: Industrial & Scientific

www.amazon.com

I've never use a comparator before. I kept begging them to get one at work, but they said they couldn't afford it. Yeah.........right.

Optical Comparator - general for sale - by owner

Sheer - Tumico Optical Comparator Model 20-4200 14 inch gradient glass screen 110 volt 50X lens X...

sacramento.craigslist.org

Comparator - general for sale - by owner

Nikon 6C 11” screen comparator. 10, 20 and 100 times lenses with surface illumination. Digital...

sacramento.craigslist.org

I just tried to use my 10x loupe and I just can't hold a scale and the loupe steady enough to get a measurement.

I have the same problem. I do have a 50x microscope for my mill than can be used with the DRO to measure also.

Can I just adjust the feed a little at the time? Or would you have to do it in the cam program?

No, it has to be changed in the CAM program, changing the pitch changes all of the G code. As the pitch changes, the start positions change. MasterCam should work just like Fusion 360.

 

[mmcmdl]

This is exactly what I love about this site . So many members willing to help with problems !

 

[alloy]

I still have the 9 start gear in steel. Went looking for it out in the shed. Pierre

I've never see a steel in a 9 tooth before. I'd be interested in buying it from you.



Yes its really nice to have help. I want to help more, but not many things fall under my experience in life.



I've looked online locally for a comparator but nothing. They seem pretty cheap.

I'm sure if I knew what the heck I was doing mastercam would do it, but that's the catch, operator error.

I'll see if I can come up with a full size comparator, hopefully desktop. But if not I'll order the one you have.

I see that fusion has a free version, but then I remember the posts about it being de-functioned.

 

[pdentrem]

Miss counted, it is a 8 tooth gear.
Pierre

 

[alloy]

I'll still take it off your hands.

 

[pdentrem]

I'll still take it off your hands.

I’ve had it for over 20 years from when we closed down the dealership.
Send me your address. I can get our driver to mail it from Buffalo NY, just cover the cost and it is yours.
Pierre

 

[alloy]

Thank you for that. PM sent.

Jim,

Did you have to model the threads in Fusion, or just put in the parameters?

I downloaded Fusion and don't see a way of doing a thread other than standard sizes.

 

[bakrch]

Thank you for that. PM sent.

Jim,

Did you have to model the threads in Fusion, or just put in the parameters?

I downloaded Fusion and don't see a way of doing a thread other than standard sizes.

You would have to create a coil to the proper pitch, then use that as a path to sweep a custom profile/sketch to draw this sort of thing up.

 

[alloy]

OK, thanks for the reply. Sounds like it will take me awhile to get that down. It seems like a lot of things in Fusion are grayed out. Is that part of the de-functioning?

G76 might be my best bet for now.