Gear Tooth Chart

[10K Pete]

Gear tooth gauges are available but are extremely expensive, like $100 for a set. Can't afford that nor do I need
those. Silly prices for some bits of stamped sheet metal!

Where can I get a printed, or printable, gear tooth chart I can use to identify various gear pitches? I've been all over Google with no joy. I just need something I can hold a gear up to and identify what the pitch is.

Anyone?

Pete

 

[Hopper]

If you just want to know the pitch, it is usually the number of teeth on the gear, plus two, divided by the outside diameter of the gear.

Gear tooth gauges are more for checking the profile of the teeth and the depth of teeth when cutting the gears etc.

There is info on the net available on how to make your own gear tooth cutters using two discs of drill rod set a certain distance apart for each pitch. That same info could be printed on paper and cut out to use as a gauge rather than a cutter. If you google homemade gear cutters you should find what you need. Has been covered in Model Engineer magazine various time over the years.

 

[Hopper]

PS, the other thing with gear tooth gauges is they require a set of 8 gauges per standard pitch as the tooth form varies for different size gears. That's a lot of gauges to lug around to identify the pitch on random gears.

 

[GLCarlson]

Boston Gear catalog has -or had, anyway- a printed chart carefully scaled to be 1:1. Just line up the the teeth. Quit at about DP32 or maybe a bit higher- not useful for metric or high pitch numbers.

 

[Geartooth]

There is a lot to choose from. Simply search "Diametral Pitch Chart" on the internet.

 

[dnalot]

Hi

Here is a useful program for gear design.

http://geargenerator.com/#200,200,100,6,1,3,1279.4999999999886,4,1,8,2,4,27,-90,0,0,16,4,4,27,-60,1,1,12,1,12,20,-60,2,0,60,5,12,20,0,0,0,2,-699

 

[10K Pete]

Well, thanks for the suggestions. I'm looking for a 'chart', if you will, that
I can hold the gear up to and determine the pitch.

Google is rife with profile charts BUT none have a scale that allows printing
to correct dimensions. NONE. So they're useless.

I'll keep looking. I suspect that one of the gear companies can send me a
chart or catalog.

Thanks,
Pete

 

[GailInNM]

This should get yu started Pete.
Gail in NM

View attachment Scan.pdf

 

[10K Pete]

Wow! Thanks Gail!

Pete

 

[GailInNM]

You are welcome Pete.
All I did was add the dimension to the laser cut file. I should have thought to do that earlier and send it to you.

You should see the laser cut set about Tuesday. It was mailed Yesterday. For others benefit, I cut Pete the above file out of thin styrene. If you find them useful, maybe I will cut a better (more durable) set out of acrylic when I get back from playing with Gauge 1 trains in Utah in about 10 days. I need to order some suitable acrylic engraving stock when I get back. I normally stock it but am out at the moment.
Gail in NM

 

[GLCarlson]

Here's the page from the Boston Gear catalog. Both PAs, reasonable range of PDs. From an oooold BG catalog.

View attachment gear_sizes.pdf

 

[10K Pete]

Thank you GL, but without some positive indicator of scale the image has no meaning. If the image had a line in it that was exactly an inch long.....

Pete

 

[GLCarlson]

I can recopy with a ruler included. Will do that and repost.

Comparisons of the published chart -the one actually in the catalog- with a random selection of actual gears shows that the original Boston Gear page was carefully printed to be 1:1 exactly. As I would have expected. Since that's the case, there is already a "ruler" in place- just print so any single tooth is to scale with a known gear, and they all are.

It's certainly true that current tech makes image scaling a problem without a reference, and including a line of known length solves that.

 

[10K Pete]

That would be wonderful if you could do that. It's sorta like the chicken
and the egg.....!

Thanks,
Pete

 

[GLCarlson]

Here ya go. File renamed to avoid confusion.
Standard 6" ruler, 10ths & 50th scale side shown.

View attachment gear_pitch_145&20.pdf

 

[10K Pete]

Beautiful! Thanks!!

Pete

 

[reeltor]

I too cut some gear profiles from card stock. I had a hard time reaching into machines to check the size with the paper one. I received a set of Boston Gear, Gear Tooth Gauges from an E-Bay win today. I pulled out my Machinery's Handbook, the page of gear teeth profiles match the gauge perfectly.
If you decide to buy a set of gauges, I checked with Boston Gear, new stock has 14-1/2 and 20 degree profiles on the same gauge. The old one that I got off of ebay that the seller represented as Boston Gear is not marked other than the DP. IIRC New Boston Gear Gauges are in the mid $200's, Enco has a set for $57-67 and Travers Tool for $49. Cheaper than most ebay sets