Author Topic: Revisiting the buttress thread.  (Read 17364 times)

Offline steamer

  • Jr. Member
  • **
  • Posts: 86
  • Country: us
Re: Revisiting the buttress thread.
« Reply #25 on: April 13, 2013, 01:18:26 PM »
I checked your references...but no threading chart.....the fact is has a 120 tooth idler tells me it has some room to play with though.

What is the stud gear, the train and the screw gear in its normal setup?....does it only have the 120 tooth idler?

Dave
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline NeoTech

  • Hero Member
  • *****
  • Posts: 826
  • Country: se
    • Roughedge Hobbyworks
Re: Revisiting the buttress thread.
« Reply #26 on: April 13, 2013, 02:36:13 PM »
The normal gears in the machine is 60 / 120 / 60 and that covers like 95% of all the threads that can be cut on the machine. The 120 idler is paired with a 127idler in a "group".. when doing imperial i run the screw from the 127 and spindle on the 120 and well there some magic happens.. i rarely do imperial.
Machinery: Optimum D320x920, Optimum BF20L, Aciera F3. -- I have not failed. I've just found 10,000 ways that won't work. http://www.roughedge.se/blogg/

Offline steamer

  • Jr. Member
  • **
  • Posts: 86
  • Country: us
Re: Revisiting the buttress thread.
« Reply #27 on: April 13, 2013, 07:41:14 PM »
OK ..so in normal operation, the 120 tooth gear is just an idler...the input shaft turns the same speed as the spindle  (60/60 =1)

60 x 5/9= 33.333.... so no love changing 1 gear.

If you can put a 50/90 cluster in between the 120 and the screw gear...step up in speed... your there.

so

(60)(120)(50/90)(60)....

I also suspect that you won't be able to use anything smaller than those gears...just because of space requirements.....due to the 120 tooth gear.

What gears do you have?
And

What DP or module are the gears?

Dave

"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline NeoTech

  • Hero Member
  • *****
  • Posts: 826
  • Country: se
    • Roughedge Hobbyworks
Re: Revisiting the buttress thread.
« Reply #28 on: April 14, 2013, 03:15:55 AM »
I do have the 50 gear but not the 90 gear... i need to figure out what module my gears have so i can make a larger one..  I think have produced more "extra" tools with my tools than actual projects since i got these machines. :D
Machinery: Optimum D320x920, Optimum BF20L, Aciera F3. -- I have not failed. I've just found 10,000 ways that won't work. http://www.roughedge.se/blogg/

Offline awemawson

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 8980
  • Country: gb
  • East Sussex, UK
Re: Revisiting the buttress thread.
« Reply #29 on: April 14, 2013, 03:45:44 AM »
That is the entire justification for my workshop - to make tools to mend tools  :ddb:

Not sure if the swarf is a byproduct or possibly the main product  :clap:
Andrew Mawson
East Sussex

Offline Swarfing

  • Sr. Member
  • ****
  • Posts: 417
  • Country: gb
Re: Revisiting the buttress thread.
« Reply #30 on: April 14, 2013, 04:25:11 AM »
Whats the outside diameter of your 120 gear and 50. Your lathe looks a similar size to mine which is a 1.25 mod. You can check the size of your gear against the HPC website as they stock standard mod gears in all sizes.
Once in hole stop digging.

Offline NeoTech

  • Hero Member
  • *****
  • Posts: 826
  • Country: se
    • Roughedge Hobbyworks
Re: Revisiting the buttress thread.
« Reply #31 on: April 14, 2013, 04:55:19 AM »
What is the HPC site??? =)
Machinery: Optimum D320x920, Optimum BF20L, Aciera F3. -- I have not failed. I've just found 10,000 ways that won't work. http://www.roughedge.se/blogg/

Offline Swarfing

  • Sr. Member
  • ****
  • Posts: 417
  • Country: gb
Re: Revisiting the buttress thread.
« Reply #32 on: April 14, 2013, 05:24:13 AM »
Once in hole stop digging.

Offline Swarfing

  • Sr. Member
  • ****
  • Posts: 417
  • Country: gb
Re: Revisiting the buttress thread.
« Reply #33 on: April 14, 2013, 05:33:01 AM »
I just tried looking up the spur gear it does not show online so you need to download the catalogue first. For an example though  a 1.25 MOD 120 teeth gear O/D = 152.5mm.

If you can't see it let me know what size yours is and i can look it up in the book i have
Once in hole stop digging.

Offline steamer

  • Jr. Member
  • **
  • Posts: 86
  • Country: us
Re: Revisiting the buttress thread.
« Reply #34 on: April 14, 2013, 09:45:59 AM »
Well Andreas....I made the cluster for my lathe....got where I needed to be eventually.... :D
I needed to make a cutter arbor for the gear cutter I bought...then I needed to make a gear arbor to hold the blanks...then modify the dividing head tailstock I had because the height didn't match the dividing head....then set it up..









its a fatal disease...there is no known cure.....
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline NeoTech

  • Hero Member
  • *****
  • Posts: 826
  • Country: se
    • Roughedge Hobbyworks
Re: Revisiting the buttress thread.
« Reply #35 on: April 14, 2013, 10:49:09 AM »
Wonderful hobby isnt it... No wonder my air rifle never gets finished. ;D
Machinery: Optimum D320x920, Optimum BF20L, Aciera F3. -- I have not failed. I've just found 10,000 ways that won't work. http://www.roughedge.se/blogg/

Offline NeoTech

  • Hero Member
  • *****
  • Posts: 826
  • Country: se
    • Roughedge Hobbyworks
Re: Revisiting the buttress thread.
« Reply #36 on: April 19, 2013, 05:02:17 PM »
So i need to cut a 90 tooth gear it has the module of 1.25, that would mean i would need to make a hob.. Or get me a gearcutter.. im a cheapskate and a hob seems interesting...

Anyone here ever made a straight cutting hob? I have seen alot of people making hobs out of different acme screws and what nots...

My main issues with hobbing is this..

1) Distance between each tooth according to the Module 1.25.
2) Does it matter how many teeth you will cut if you use a hob? (Im pretty sure it doesnt matter
3) The depth of the tooth can be calculated by doing 3.14159 * Mod (1.25) == 3.926mm (or am i completely off now?)
Machinery: Optimum D320x920, Optimum BF20L, Aciera F3. -- I have not failed. I've just found 10,000 ways that won't work. http://www.roughedge.se/blogg/

Offline NeoTech

  • Hero Member
  • *****
  • Posts: 826
  • Country: se
    • Roughedge Hobbyworks
Re: Revisiting the buttress thread.
« Reply #37 on: April 19, 2013, 05:16:13 PM »
Uhm.. i made a rack in Solidworks and checked the tooth depth.. So the distance between tooths is 3.14 * module. ..

But it seems at a Module 1, the depth of the tooth is 2.25.. i cant reverse or derive this number (and i need to understand why its 2.25).
Machinery: Optimum D320x920, Optimum BF20L, Aciera F3. -- I have not failed. I've just found 10,000 ways that won't work. http://www.roughedge.se/blogg/

Offline steamer

  • Jr. Member
  • **
  • Posts: 86
  • Country: us
Re: Revisiting the buttress thread.
« Reply #38 on: April 20, 2013, 12:42:47 PM »
I think its Ivan Laws book.   GEARS AND GEAR CUTTING shows how to make your own flycutters for making gears

Dave
« Last Edit: April 20, 2013, 07:34:06 PM by steamer »
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline vtsteam

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 6466
  • Country: us
  • Republic of Vermont
Re: Revisiting the buttress thread.
« Reply #39 on: April 20, 2013, 10:36:11 PM »
For flycutting gears:

Making gear cutters with taper drills:

http://mikesworkshop.weebly.com/making-gear-cutters.html

(See also 2 updates and improvements on the method at Mike's workshop site.)

Cutting gears:

http://www.deansphotographica.com/machining/projects/109/gears/109c.html

John Stevenson article:

http://www.metalwebnews.com/howto/gear/gear1.html

Hobbing with rack type hob:

http://www.jeffree.co.uk/pages/multi-tooth-gear-cutter.htm

I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline hopefuldave

  • Full Member
  • ***
  • Posts: 189
  • Country: gb
Re: Revisiting the buttress thread.
« Reply #40 on: April 21, 2013, 03:23:43 PM »
Quote from: NeoTech
Uhm.. i made a rack in Solidworks and checked the tooth depth.. So the distance between tooths is 3.14 * module. ..

But it seems at a Module 1, the depth of the tooth is 2.25.. i cant reverse or derive this number (and i need to understand why its 2.25).

Uh huh, the pitch of a rack ( or a worm...) is "unwinding" the teeth, so going from diameter of the pitch circle to the circumference means multiplying by Pi, for metric module pitches, mod times Pi, but for "English" DP divide Pi by the DP, simples :) so for your 1.25 mod hob, you need the "teeth" to repeat at Pi Times 1.25 mm.

The depth of cut, 2.25 x mod, is because an involute gear needs clearance at the bottom of.the tooth space, in an ideal world the cut would be 2 x mod, but that leaves no room for grease, grit, badly-formed teeth...
On larger gears, the clearance can be less, as there's more room to play with, so for a 5 mod it could be reduced to 0.125, giving q cut of 2.125 times the mod, or less.

So... Your hob needs teeth pitched at Pi x Mod, with an included angle of twice the pressure angle, and a depth of 2.25 x Mod. This won't be a "topping" cutter, as far as I can tell, so the gear blank will need to be the correct diameter ( teeth+2 x Mod)...

Hope that makes.sense!

Dave H. (the other one)
Rules are for the obedience of fools, and the guidance of wise men.