Poor Man's Dividing Head

[robcas631]

Excellent job!

 

[gus]

Hi Phil,
Looks good.You beat me hands down in the competition---------Cheapest and nastiest dead centre!!!!.
You also have a Rolls-Royce Dividing Head. Plan to copy and make LMS D.H. using my own DIY worm and wheel.
Will be tough to keep to a small gear box housing with Scrap Material on hand.

My DIY Gear cutting took a long time to happen. Need a pinion gear for the timing gear chain badly and USA /UK vendors won't ship to Singapore.

 

[Philjoe5]

Gus,

Looks good.You beat me hands down in the competition

Not true. You've made gears, I haven't.

But you definitely got me going in the right direction. I kept putting gear making off because involute gear cutters in the US tend to run about $45 each, so a set of 8 = $360. But the CTC set of 8 = $125, so that's a good place to start learning how to make gears. Thanks for the tip to CTC Tools

Cheers,
Phil

 

[gus]

I think Gus meant $125...I hope so 'cause that's what I just paid for a set from the same vendor!!!

Gus, did you give the guys at CTC Tools some of your fresh fish for that discount??

Phil

Sorry Guys,

Just checked CTC Bill and its $74 per set for the Module 0.8 and $85.50 for the Module 1.

 

[gus]

Gus,



Not true. You've made gears, I haven't.

But you definitely got me going in the right direction. I kept putting gear making off because involute gear cutters in the US tend to run about $45 each, so a set of 8 = $360. But the CTC set of 8 = $125, so that's a good place to start learning how to make gears. Thanks for the tip to CTC Tools

Cheers,
Phil

Please post the very first good gear. Watch the cut depth. I cheated.Measured a gear sample. Blunt or very sharp tooth means depth error. I am still working out depth calculation. I am wondering tooth height equals O.D.--Pitch Diameter???.

 

[Philjoe5]

Gus,
This is what I know so far:

[FONT=&quot]To find diametrical pitch, DP [/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]DP = # teeth in a gear + 2 ÷ Outside diameter[/FONT]

[FONT=&quot][/FONT]
[FONT=&quot]Then I found this equation:[/FONT]
[FONT=&quot]
[/FONT]
[FONT=&quot]Depth of cut = 2.157/DP[/FONT]



[FONT=&quot]I did the following calculation for one of the module 1 change gears for the G0602 lathe:[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]52T gear has an OD of 2.120”[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]Diammetrical Pitch = 54/2.120 = 25.47[/FONT]
[FONT=&quot] [/FONT]
[FONT=&quot]Depth of cut = 2.157/25.47 = 0.0847” which agrees with the cut on the video[/FONT]

[FONT=&quot][/FONT]


I watched a video of a guy on youtube cutting a module 1 gear which requires a depth of cut of 0.085". He did it in one pass. Seems like a hefty cut.

[ame]http://www.youtube.com/watch?v=xRmQpSGUAY8[/ame]

Is that how you cut your gear?

Please post the very first good gear

Ah, the teacher wants to know if the student has learned his lesson

Cheers,
Phil

 

[radial1951]

....I am still working out depth calculation. I am wondering tooth height equals O.D.--Pitch Diameter???.

Hey Gus, Below is a drawing showing the tooth proportions for Module System metric gears. (DP system inch gears have a different depth ie 2.157/DP)

The whole depth of tooth is 2.25 x m (The 0.25m is the extra depth at the bottom of the tooth space to give clearance for the teeth of the mating gear)

So, if m = 0.8 , then depth = 2.25 x 0.8 = 1.8mm (this gives 0.2mm extra depth for the clearance)

BUT be careful!! All of this assumes every dimension on the gear blank and cutter profile are PERFECT. And that includes concentricity to the bore.

If the cutter profile is correct, then the ONLY thing that really matters is the Pitch Diameter, because that determines the tooth thickness and the size of the gap between the teeth.

If you cut a whisker too deep, the teeth will be a bit thin, but the gear will still work ok, just a bit more backlash (you need a little anyway).

Keep having fun and posting, this is interesting.

Regards, RossG
radial1951
_____________

 

[gus]

Hey Gus, Below is a drawing showing the tooth proportions for Module System metric gears. (DP system inch gears have a different depth ie 2.157/DP)

The whole depth of tooth is 2.25 x m (The 0.25m is the extra depth at the bottom of the tooth space to give clearance for the teeth of the mating gear)

So, if m = 0.8 , then depth = 2.25 x 0.8 = 1.8mm (this gives 0.2mm extra depth for the clearance)

BUT be careful!! All of this assumes every dimension on the gear blank and cutter profile are PERFECT. And that includes concentricity to the bore.

If the cutter profile is correct, then the ONLY thing that really matters is the Pitch Diameter, because that determines the tooth thickness and the size of the gap between the teeth.

If you cut a whisker too deep, the teeth will be a bit thin, but the gear will still work ok, just a bit more backlash (you need a little anyway).

Keep having fun and posting, this is interesting.

Regards, RossG
radial1951
_____________

Hi Ross,

Thanks for the formula. I did messed and gear tooth was razor sharp but the second and final turned out OK. However the cut pinion is Module 0.8 and the big purchased gear was Module 0.75 but meshing turned out OK.

 

[Philjoe5]

OK Gus. As promised, my first 2 gears, one steel one aluminum (for practice)




Thanks for the help

Cheers,
Phil

 

[Brian Rupnow]

This must be international gear day!!! I just made a set for my engine.---Brian

 

[AussieJimG]

Those gears look pretty good Phil, did you use your rotary table or the borrowed one?

Jim

 

[Philjoe5]

Hi Jim,
Thanks. Pics can be a bit deceiving. The tooth profile is a little off because I didn't have the cutter height set at dead center.

When I began making the 60T gears to go with these 30T gears I set the cutter properly and got a good profile. But when I was cutting the 55th tooth, my rotary table 2 degree ring moved when the table didn't:wall:. That caused me to bugger the gear

To answer your question, yes the rotab was used to make these gears and when it's adjusted properly should work just fine. I'll give it another try this weekend.

It's a challenge. I don't know if my first set of gears are useable. When I make their 60T mates I could try them out but I'm still on the learning curve.

It was good talking to you the other night. When I can unfocus from the gear making I'll check out skype.

Cheers,
Phil

 

[gus]

Hi Phil,

Looks good and far better looking than my very first gear which had sharp tooth. It is true plus and minus a whisker the gear profile will look odd.

Confession:
Bought 20t 30t 40t 50t 60t gears to be used as dividers to save all the trouble of making divider plate. Trying hard to stay away from TokyuHands.I have too many hobbies and they have too many items that Gus wants to buy to satisfy his greed not his need.:wall:

 

[workshopman]

Having arrived home from a three week holiday to the inevitable pile of correspondence and other items to attend to I eventually came to the June project of the month news letter and spotted the Poor man's dividing head which took my attention.

Looking this up, I found Gus that you were again making your own version of one of my designs, last time I think the boring head. I must say the dividing head is looking good. For me, I get as much encouragement by someone adapting my designs to suit purpose, or to use available materials, as I do if someone follows my drawings exactly.

The thread is rather long so I have not found the time to study it in depth, but I did notice you commented that you would need to make a tailstock for making pinions. As I have not seen a picture of a tailstock I am not sure if you have made it. If not, then you may be interested in my method which I have used very successfully. I am not sure how to post a photograph so have added it to a blank page on my web site, here.

The only explanation needed is that the hole must be a close fit on the pinion blank and the slot on the side of the bar is made when cutting the first gear space.

To see the reason for me cutting pinions see here

If I may digress may I also mention my latest addition to my website. This is major update on my rather unconventional quick change lathe tool holders.

Harold Hall

 

[gus]

Having arrived home from a three week holiday to the inevitable pile of correspondence and other items to attend to I eventually came to the June project of the month news letter and spotted the Poor man's dividing head which took my attention.

Looking this up, I found Gus that you were again making your own version of one of my designs, last time I think the boring head. I must say the dividing head is looking good. For me, I get as much encouragement by someone adapting my designs to suit purpose, or to use available materials, as I do if someone follows my drawings exactly.

The thread is rather long so I have not found the time to study it in depth, but I did notice you commented that you would need to make a tailstock for making pinions. As I have not seen a picture of a tailstock I am not sure if you have made it. If not, then you may be interested in my method which I have used very successfully. I am not sure how to post a photograph so have added it to a blank page on my web site, here.

The only explanation needed is that the hole must be a close fit on the pinion blank and the slot on the side of the bar is made when cutting the first gear space.

To see the reason for me cutting pinions see here

If I may digress may I also mention my latest addition to my website. This is major update on my rather unconventional quick change lathe tool holders.

Harold Hall

Hi Harold,
Thanks for the support and kind advice. You are my revered "Sensei" and Gus a very non-conforming(or non-compliant) disciple. For this Gus would get evicted out of ShaoLin Martial Art Temple,China. Every time I need some help,I would run to your books for reference. I had to make do with surplus material. Plan to make the DH with Dividing Plates.

P.S. Took up ShaoLin Martial Ar tfor 3 1/2 years and learnt nothing but became physically and mentally fit to scrape thru the local part-time,night HND Engineering Diploma Course in the 1960s.
Just came back from Osaka,Japan and bought spent too much at the TokyuHands Hobby Supermarket where they sell every thing for every hobbies.

 

[Stub Mandrel]

Harold Hall - the only man in the world who lets his wife's friend use his dividing head to make cakes! ;-)

Neil

 

[gus]

Hi Gurus,

Dividing Head totally completed with dividing plate/gears good for 20--------60T.
Bought the gears from TokyuHands,Osaka,Japan and they cost an arm and a leg.Number of teeth stamped on gear.
In the long run, will save money cutting DIY gears. Making the DIY Dividing Plates for a bigger
range of gear tooth will challenging.
Need some tips how to make own conventional Dividing Plates. Will be cutting a gear train to run Sakai Spindle speed at 50----150 rpm to cut threads.
Also need some advice how to I.D. Module no.

 

[Philjoe5]

Gus,
A calculation for module number is:

(Number of teeth + 2) divided by the outside diameter in millimeters

Your dividing head looks good.

Cheers,
Phil

 

[workshopman]

I think Neil we should explain your comments about my wife's friend.

For an explanation, see here http://www.homews.co.uk/page504.html

Harold Hall

 

[gus]

HI Gus,

I made my worm & wheel in two stages. First cut two matching worm gears one to use and the other one couple of thou oversize and in silver steel (drill rod). Cut some teeth in the silver steel one and harden & temper it to make a cutter.

Using a thin cutter (maybe a slitting saw) rough out the teeth in the worm wheel blank, at the helix angle. Now mount the worm gear blank so it can rotate freely and feed it into the cutter you made. This will take more pressure than you expect because the teeth on the cutter aren't relieved.

Tip - use free cutting (leaded) brass for the worm wheel otherwise you can end up with an extra tooth (don't ask how I know this).

For ordinary gears I cut in one pass with the cutter working normally, and then run back in the climb milling direction which puts the polish on them.

I use home made single point cutters.

Neil

Hi Neil,
Sorry for this late reply. The gear box is fantastic.
Neil has raised the bar and we will a tough time to catch up.
I am all set to cut 20 30 40 50 60t gears with my not so cheap dividing gears/plate. Planning to cut worm and wheel soon as the slow speed gear train arrive from Korea. Meanwhile I may figure out making my own to jump start. The HMEM is a great and friendly forum with helpful members.
"70" young man recovering from the "6 day shop till we drop" holiday in Osaka. Now finishing up the petrol fuel tank for ''Webbie".