Model Engine Maker

Help! => Mistakes, muckups, and dangerous behaviour => Topic started by: Don1966 on September 19, 2012, 11:50:24 PM

Title: Making My First Gear
Post by: Don1966 on September 19, 2012, 11:50:24 PM
Today was my first try at making a gear. And as you will see it did not turn out to good. I managed to cut the blank out and bore with no problem. When it came time to cut the teeth that was another thing  :facepalm:. I hope I am not the only one who has made this mistake and hope it is the last time I do make it.
The dial Collar on my RT slipped and caused me a mishap in one spot on my gear, of coarse the rest of the teeth would be off also. When I reached tooth number 7 the collar slipped and didn't notice it till tooth number 9. Below are photos of the progression. It will be a will before I can make another work take preference.
If anyone sees that I did something wrong here. Please point it out? :Director: :slap:

Cutting the Blank
cu(http://i1247.photobucket.com/albums/gg629/don1966/MAKING%20A%20GEAR/DSC02797_zpsee05daba.jpg)
Boring the blank
(http://i1247.photobucket.com/albums/gg629/don1966/MAKING%20A%20GEAR/DSC02799_zps37404ef4.jpg)
(http://i1247.photobucket.com/albums/gg629/don1966/MAKING%20A%20GEAR/DSC02800_zps50ee9575.jpg)
The finished blank
(http://i1247.photobucket.com/albums/gg629/don1966/MAKING%20A%20GEAR/DSC02801_zps402f23e7.jpg)
Setting up the Mill and finding the mid point
(http://i1247.photobucket.com/albums/gg629/don1966/MAKING%20A%20GEAR/DSC02802_zps276c0777.jpg)
Adjusting the cutter to mid point
(http://i1247.photobucket.com/albums/gg629/don1966/MAKING%20A%20GEAR/DSC02804_zps48e86b0e.jpg)
Cutting the Gear
(http://i1247.photobucket.com/albums/gg629/don1966/MAKING%20A%20GEAR/DSC02805_zpsc4961e33.jpg)
This photo is where I marked the dial should it move again
(http://i1247.photobucket.com/albums/gg629/don1966/MAKING%20A%20GEAR/DSC02807_zps9aec7f0a.jpg)
This is a photo to show the large tooth
(http://i1247.photobucket.com/albums/gg629/don1966/MAKING%20A%20GEAR/DSC02806_zps0f5ba13a.jpg)

Don
Title: Re: Making My First Gear
Post by: steamer on September 20, 2012, 12:26:03 AM
Hi Don
Sounds like.....for whatever reason...there was an index error.....probably when the dial
slipped.     I did something similar with my Wallaby build.

I would set that gear back up , like I did, and cut some more teeth for practice.
Then I would make a new blank and start again.
Sorry bud

Dave
Title: Re: Making My First Gear
Post by: tel on September 20, 2012, 12:45:06 AM
Yeah, happens all the time, don't sweat it. I've cut well over 100 gears and still throw the odd silly one.
Title: Re: Making My First Gear
Post by: Don1966 on September 20, 2012, 12:53:50 AM
Thanks Dave and Tel I hope the next one goes a lot better. I just have to keep focused on what I am doing. Dave the spreadsheet you gave me is great. I still struggle with setting the seconds they are so close. Hope next week I can try again. The is the 34 tooth gear for metric conversion of my Myford.

Don
Title: Re: Making My First Gear
Post by: steamer on September 20, 2012, 12:55:22 AM
Something to keep in mind with resettable dials on any machine tool    Don't turn the crank by the dial, but by the dial handle.    ......and yes I screw this one up all the time....  :facepalm: :wallbang:

If it locks with a set screw just make sure its nice and snug. .....I screw that one up all the time too!

The mistake I made cutting the cam gear on the Wallaby was I forgot to tighten up the collet holding the mandrel!.. :facepalm: :ROFL:

Well....if you don't make any mistakes...it just means you not doing anything....the next one will go faster...I promise Buddy!

Dave
Title: Re: Making My First Gear
Post by: steamer on September 20, 2012, 12:57:50 AM
I'm glad the spreadsheet is helping Don!  I'm going to need to use it myself when I put the 60 hole circle in my SB pulley....

Definitly set that bugger back up and cut some more teeth ....nothing to lose, and you'll get a better feel for the whole set up.

Dave
Title: Re: Making My First Gear
Post by: Maryak on September 20, 2012, 01:07:00 AM
Don,

Sorry to read about your Oops. If I am looking at things correctly, you are starting the cut from the back of the blank, so it's difficult to  see what's going on until it's too late.

May I suggest you either turn the cutter 180 and reverse the rotation, or start the cut from the other side of the blank,  or put the RT on the other end of the mill table.

Edit:

Lastly, prove your indexing.

(http://i389.photobucket.com/albums/oo340/Maryak/Hit%20and%20Miss/IMG_1236.jpg)

Hope this helps

Best Regards
Bob
Title: Re: Making My First Gear
Post by: Don1966 on September 20, 2012, 01:09:01 AM
Thanks I will finish the gear for a test run. And I do have a habit of turning the dial by the collar instead of the crank and it is a slip collar. I also have a video by Swarfrat on the RT. this is how I learn to read minutes and seconds.

Don
Title: Re: Making My First Gear
Post by: Don1966 on September 20, 2012, 01:11:06 AM
Thanks Bob I will try that.

Don
Title: Re: Making My First Gear
Post by: tel on September 20, 2012, 01:16:40 AM
Thanks Dave and Tel I hope the next one goes a lot better. I just have to keep focused on what I am doing. Dave the spreadsheet you gave me is great. I still struggle with setting the seconds they are so close. Hope next week I can try again. The is the 34 tooth gear for metric conversion of my Myford.

Don

There's 99% of gear cutting success right there.
Title: Re: Making My First Gear
Post by: tel on September 20, 2012, 01:17:53 AM
... the other 1% is remembering to turn the mill on. :Lol:
Title: Re: Making My First Gear
Post by: steamer on September 20, 2012, 01:20:47 AM
The dropbars get the other 5% tho.....usually on the last tooth!

)*&#$) dropbars!

Dave
Title: Re: Making My First Gear
Post by: Don1966 on September 20, 2012, 01:26:24 AM
Hey didn't want to get your feathers ruffed. I can bad memorys are surfacing here.

Don
Title: Re: Making My First Gear
Post by: steamer on September 20, 2012, 01:30:17 AM
 :ROFL:

Dave
Title: Re: Making My First Gear
Post by: rhitee93 on September 20, 2012, 02:25:28 AM
If it makes you feel better Don, I am impressed with how far you got.  This is something I have never tried.
Title: Re: Making My First Gear
Post by: Don1966 on September 20, 2012, 02:33:12 AM
Thanks Brian but I did a lot of reading before I started. And followed some threads.

Don
Title: Re: Making My First Gear
Post by: Don1966 on November 05, 2012, 06:58:36 PM
Well here is my second attempt to produce a gear. I must say this time it was a whole lot easier to do. After finishing the first gear I messed up, it gave me some practice and confidence. Thanks Dave for telling me to finish it. The spread sheet helped a whole lot, I don't think I could of done it without it. I am rather proud of it since it is my first completed gear. I did not have a broach for the key way, but I had something just as good. I used my Rockwell Blade runner. For anyone who doen't know what that is its a upside down Jig saw with a table top. a very useful piece of equipment. This is the link to it https://www.rockwelltools.com/en-US/bladerunner_wall_mount.aspx?gclid=CK-BhpzAuLMCFRR7nAodAF0Aew I don't have any connection to this product.
Below are the photos of my gear.
In the second photo you will see the tape and mark to keep the collar from slipping again on me.
Title: Re: Making My First Gear
Post by: tel on November 05, 2012, 07:17:53 PM
You done good Don!  :ThumbsUp:
Title: Re: Making My First Gear
Post by: steamer on November 05, 2012, 07:39:25 PM
Congrats Don!

Glad it worked out for you!

Dave
Title: Re: Making My First Gear
Post by: Jo on November 05, 2012, 08:01:53 PM
 :ThumbsUp: Doesn't it feel good when it works 8)!

Jo
Title: Re: Making My First Gear
Post by: Don1966 on November 05, 2012, 09:19:40 PM
Thanks Tel, Dave and Jo, I do have more confidence now that it is done. I finally have the hang of dialing in the seconds. Although they are so close together. I just have to remember when I have odd minutes dial in the even minuites and start at 120 to dial the last minute. Then start the seconds from 60. when even minutes dial in the minutes and start from 120 to dial in the seconds. I think that is correct.

Don
Title: Re: Making My First Gear
Post by: vcutajar on November 05, 2012, 09:54:44 PM
Well done Don.  :ThumbsUp:

I still have to learn to cut gears.  Maybe next year after I finish the current build.

Vince
Title: Re: Making My First Gear
Post by: smfr on November 05, 2012, 09:56:16 PM
Nice, Don! Looks like that little 4" Phase II rotary table did it's job well.

Simon
Title: Re: Making My First Gear
Post by: Maryak on November 05, 2012, 10:40:58 PM
Congrats Don!

Glad it worked out for you!

Dave

Me 2  :NotWorthy:

Best Regards
Bob
Title: Re: Making My First Gear
Post by: V 45 on November 05, 2012, 10:58:30 PM
Well done Don !! I haven't cut any gears ...ever !! Very nice job !  :ThumbsUp:
I will have to take notes on this one.
  Dave
Title: Re: Making My First Gear
Post by: ScroungerLee on November 05, 2012, 11:04:28 PM
Nicely done Don.  Only one for the scrap bin before getting a good one?  Better than the few I have made!

Lee
Title: Re: Making My First Gear
Post by: Don1966 on November 06, 2012, 12:13:46 AM
Thanks guys for the kind comments, it does feel good to have made one. Now I need to figure out how to make bevel gears. Anyone have a spread sheet on them? I did make my own on the spur gear and worm gear, but haven't found the formulas for the bevel gear.

Don
Title: Re: Making My First Gear
Post by: b.lindsey on November 06, 2012, 12:50:31 AM
Its kind of like seeing your first engine running...all smiles. Congrats Don!!!

Bill
Title: Re: Making My First Gear
Post by: Bezalel on November 06, 2012, 01:07:33 AM
Well done Don


Gears are still on my to do list, so take this with a grain of salt.


Aren't they the same as spur gear tables but only applied to the outer edge of the bevel?


does any one out there know?


Bez
Title: Re: Making My First Gear
Post by: zeeprogrammer on November 06, 2012, 01:13:29 AM
Congrats Don. Nice job.
I've never done a gear myself and the pics and your attitude will make it easier for me.
Title: Re: Making My First Gear
Post by: gbritnell on November 06, 2012, 01:21:39 AM
Great work Don,
I always enjoy making gears, when they come out right. Something so simple gives so much satisfaction.
gbritnell
Title: Re: Making My First Gear
Post by: Don1966 on November 06, 2012, 01:26:50 AM
Its kind of like seeing your first engine running...all smiles. Congrats Don!!!

Bill
Your right Bill, it does feel like it. I had always thought that it was out of my ability to do.

Thanks Bez, I don't think they are the same I my be wrong, but someone will let us know.

Thanks Carl, I am glad you are getting some confidence from my accomplishment.

Don
Title: Re: Making My First Gear
Post by: Don1966 on November 06, 2012, 01:29:44 AM
Great work Don,
I always enjoy making gears, when they come out right. Something so simple gives so much satisfaction.
gbritnell
Thanks George, it is simple once you understand how to do it and satisfying.

Don
Title: Re: Making My First Gear
Post by: swilliams on November 06, 2012, 01:42:51 AM
Yes - well done Don, it was fun to share the journey with you.

I have some material copied from old Brown and Sharp books (I got on ebay) on cutting bevel gears with spur gear cutters. I imagine it's well out of copyright. If anyone wants it send me a message with your email and I'll send it onto you. If someone manages to make some then they can show the rest of us how it all goes  ;)

Steve
Title: Re: Making My First Gear
Post by: Pete49 on November 06, 2012, 02:22:19 AM
Nicely done Don :cartwheel: Did you use the RT you made? The only gear I have made to date is the worm gear (and got lucky) for my attempt at your RT build
Pete
Title: Re: Making My First Gear
Post by: Don1966 on November 06, 2012, 02:34:31 AM
Nicely done Don :cartwheel: Did you use the RT you made? The only gear I have made to date is the worm gear (and got lucky) for my attempt at your RT build
Pete
Thanks Pete,  I didn't make the RT it is store bought unlike the one you are building it also has a dividing plate.

Thanks also to you Steve I sent you a PM.

DON
Title: Re: Making My First Gear
Post by: Maryak on November 06, 2012, 04:37:18 AM
Aren't they the same as spur gear tables but only applied to the outer edge of the bevel?


Bez

Sorry Bez,

To make a bevel gear on a mill you make a parallel depth bevel and the cutter must match the inner edge of the bevel tooth so that when you angle it left and right to cut the outer edges it still passes through the original cut on the tooth centre line without removing any metal. A minimum of three passes for each tooth using this method.

Hope that helps

Best Regards
Bob
Title: Re: Making My First Gear
Post by: Bezalel on November 06, 2012, 05:16:30 AM
Hi Bob


No need to apologies for educating me.  :help:


That makes a lot of sense - If it was the same as a spur gear on the outer edge, I'd have to find a way to make the cutter get narrower as it cuts towards the apex of the bevel.   :facepalm:


It looks like more reading is in order, before I will be able to ask any meaningful questions on the subject.


Cheers


Bez
Title: Re: Making My First Gear
Post by: Maryak on November 06, 2012, 06:09:34 AM
Bez,

There's no such thing as a stupid question. I was not born knowing this stuff, somebody, in fact a lot of somebodies, taught me and helped me and there are many more things I don't understand, such as casting, than those I do understand.

Best Regards
Bob
Title: Re: Making My First Gear
Post by: Dan Rowe on November 06, 2012, 03:03:00 PM
Don, Nice work on the gear. :ThumbsUp:

Bob,
There is a gear cutter for bevel gears in the mill. It is a thin form of cutter so it will fit the small end. I do not think they are made any more but they show up on ebay all the time mostly in the larger pitches so not much use for model work.

Dan
Title: Re: Making My First Gear
Post by: Don1966 on November 06, 2012, 03:12:02 PM
Thanks guys for the info much appreciated.

Don
Title: Re: Making My First Gear
Post by: mklotz on November 06, 2012, 03:18:57 PM
There was a long and I thought useful bevel gear discussion back on HMEM when we were all there...

http://www.homemodelenginemachinist.com/f26/bevel-gear-cutting-involute-cutters-9699/

[I hope John doesn't kick me out the door for referencing them.]
Title: Re: Making My First Gear
Post by: Dan Rowe on November 06, 2012, 03:59:38 PM
Marv,
Yeah that was a good thread.

The thin form of bevel gear cutters has a big disadvantage over the parallel depth method. Using the thin form requires each tooth to be filled on both sides of the tooth for smooth operation. This is because the pitch of a bevel gear changes from the big end to the small end of the gear.

The parallel depth method does not need to be filed for smooth running. They are designed from the small end so the cutter will fit the small end.

I finally found a reasonably priced set of gear gauges and now I realize why the pitch of bevel gears is for the big end. The gear gauge only works well on the big end.

Dan
Title: Re: Making My First Gear
Post by: zeeprogrammer on November 06, 2012, 11:53:45 PM
[I hope John doesn't kick me out the door for referencing them.]

I thought there were plenty other reasons. But you're still here. Which gives me hope for myself.  :ROFL:

If anyone kicks you out the door...a crowd will be coming along. (Need agreement on the definition of a crowd.)
Title: Re: Making My First Gear
Post by: Pete49 on November 07, 2012, 01:49:06 AM
Marv I can't see why you would think that as a lot (another for Carl to ponder) of us enjoyed the site before it was sold from under us without as much of a 'Goodbye and thank you for all the fish'. Sorry I'll let it lie. back to topic. The admins on this site would know its not a move to get us to go back but an easier method than trying to get the whole thread moved here
Pete (who has probably overstepped his mark)
Title: Re: Making My First Gear
Post by: zeeprogrammer on November 07, 2012, 03:10:25 AM
My little nickel's worth...

One bad apple doesn't always spoil the bushel.
Lots of good stuff back there and put there with the same reasons and emotions as here.

Now...a bad egg on the other hand...  ;D
Title: Re: Making My First Gear
Post by: Don1966 on November 20, 2012, 12:41:44 AM
Just received my book today on "Gear Design Simplified" this book covers everything about gears and all types in simple format so you can understand it. It has all the formulas you need. If you don't have this book and want to learn about gears get it.

Don