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View Full Version : Yet another involute gear cutter question...



Rif
10-26-2007, 10:43 AM
Last week, I ordered 3 involute gear cutters, from wttool. (18 Pitch, 20 degree PA, #2, #3, and #4) Today, I get an e-mail stating that the #4 gear cutter is a close-out item and is no longer available, so it has been canceled. :mad: The other 2 are being shipped.

Other than E-bay, for which I haven't seen any 18 pitch gear cutters available, is there any other source for these gear cutters that has a more down-to-earth price? One source wants almost 100 GB Pounds for this cutter....which would be around $200.

I remember reading that a gear cutter is really only 100 percent accurate for 1 particular tooth in it's range. That being the case, is a #3 (35-54 teeth per gear) the most accurate when cutting 35 or 44.5 teeth? (Yeah, I know, 44.5 teeth don't exist...I just used that number because it is the average of 35 to 54.) What I am wondering is if I could cheat and use the #3 cutter to cut a couple of 30 tooth gears and a 32 tooth gear?

Thanks,

Brian

John Stevenson
10-26-2007, 04:10 PM
They are most accurate at the lowest number.

.

Rif
10-26-2007, 04:37 PM
They are most accurate at the lowest number.

.

So, if I understand correctly, the #3 is the most accurate at 35 teeth. So, cutting 34 teeth with a #3 would be as accurate or more accurate than using a #4 to cut 34 teeth? If I understand you correctly than I will be fine using a #3 to cut 30 and 32 teeth.

Thanks!

Brian

SGW
10-26-2007, 04:55 PM
Try MSC or Travers www.mscdiret.com or www.travers.com

ammcoman2
10-26-2007, 06:58 PM
Victor Machinery also has them http://www.victornet.com/cgi-bin/victor/productlist.html

Don't know how the price compares though.

Geoff

John Stevenson
10-26-2007, 07:14 PM
Brian,
Don't let it worry you.

http://homepage.ntlworld.com/stevenson.engineers/lsteve/files/30_32_35.BMP

The green is the 30 T, the red is the 32 and the blue is the correct 35 tooth.
Not enough difference to strangle a gnat.

.

dp
10-26-2007, 07:34 PM
Sir John, you are a master practitioner of the notion that a picture is worth a thousand words. Another of your gems - this demonstration of knurling wheels and the relevance (or irrelevance) of work diameters:

http://homepage.ntlworld.com/stevenson.engineers/lsteve/hidden/knurltest1.jpg

http://homepage.ntlworld.com/stevenson.engineers/lsteve/hidden/knurltest2.jpg

lane
10-26-2007, 07:55 PM
Travers Tool has the best prices I have ever found on Gear cutters .

Rif
10-26-2007, 08:20 PM
Brian,
Don't let it worry you.

The green is the 30 T, the red is the 32 and the blue is the correct 35 tooth.
Not enough difference to strangle a gnat.

.

Great! Thanks! I won't worry about it then. Once I get the cutters, I am going to start cutting the gears and soon my old P&W will be able to cut threads again.

Regards,

Brian