Anyone here capable of gear cutting?

[awemawson]

Make a roll of Plasticine, flatten it on the bench, roll your gear along it to form a rack in the Plasticine, Cut along the centre of your rack to give a sharp edge, and measure the inclination of the teeth with a protractor. You may need to chill the Plasticine in the 'fridge before you slice it to avoid 'pulling'

Andrew

[Sunset Machine]

This could get you into trouble, but 14.5's are kinda pointed, 20's look like pyramids. I'd have to check, but I thought all metrics were 20 degrees. Or 14.5's..?

[stevec]

Have you looked at Misumi? Here's a link to the gears section of their humongous catalogue.Misumi gears

[PixMan]

I do think this may be the 14.5º pressure angle teeth.

I went to the Musumi site but they didn't seem to have anything in steel the right size. I think I'll be OK with getting someone on the "other machinist" website to help out. I make the blanks, I get some one to cut them.

Perhaps I could probably try doing it on my rotary table if I set it on the vertical, but a chuck for it and get a smaller gear tooth cutter. I just don't know if the Phase II rotary table has the accuracy to make a decent gear.

[Mayhem]

(12-21-2013, 08:10 AM)PixMan Wrote: ...I just don't know if the Phase II rotary table has the accuracy to make a decent gear.

Only one way to find out Ken

[PixMan]

I went over to the shop, got out my Starrett C19 protractor and using a pencil I scribed 20º (40º included) and 14.5º (29º included) triangles on a piece of paper. The gear teeth in the borrowed 70 tooth gear seemed to line up with the 20º pressure angle, so I guess that's what it is.

Being the holiday season I don't have funds to buy a 6" chuck for my rotary table nor a gear tooth cutter and arbor (though I could make one of those), so I'm going the cheaper route and get someone on PracticalMachinist.com to cut the teeth in a blank I'll make.

I checked the gears I have in the machine right now, they are 127, 105, 50, 25, and 20. With the added 70 tooth gear, I'll be able to cut metric thread pitches of 0.25, 0.5, 1.0, 1.25, 1.5, 2.0, 2.5, 3.0 and 5.0. Adding the 30 and 35 tooth gears later will get me 0.75, 1.75, 4.0 and a couple others. Not on the list would be 0.7, but I doubt I'll need to ever cut an M4x0.7 thread that I couldn't cut with the dies I have.

Switching the machine out to cut metric gears should be simple, but on this machine I have to remove the toothed wheel for the 5C collet closer. Indicating it back into running true is a big PITA, so I will use dies for most metric threads I may have to do. All that until I get the shop moved and can install and run the YAM CNC lathe that Russ is giving me. With that machine, no restrictions on threading, and for once I'll finally be able to cut pipe threads without a die! My Victor 1640 lathe doesn't have the no-longer-available taper attachment, and the last one the importer had sold for over $1,700. Even if they had one, it wouldn't be me buying one at that price. If I ever find one of these lathes that has it, I'll see if I could reverse engineer the assembly and make my own. The taper attachment and having two other gears, 28 and 35, would allow me to cut 27 pitch imperial threads.

[tekfab]

Okay I'm going blind, your saying 20deg pressure angle but what mod ? Its just that the HPC prices seem to be way cheaper than prices you seem to have been quoted ?
Mike

[PixMan]

Module is 1.75. I didn't find any ready-made ones (or even ones I would have to face to the right width) for less money than the quote for hobbing teeth. I would also have to modify the bore and keyway in the ready made ones.