Needs Pictures: 0
Picture(s) thanks: 0
Results 16 to 25 of 25
Thread: 17 tpi thread
-
2nd Feb 2020, 06:09 PM #16Senior Member
- Join Date
- Nov 2008
- Location
- Sydney
- Posts
- 112
-
2nd Feb 2020, 08:15 PM #17Member
- Join Date
- Nov 2018
- Location
- Tasmania
- Posts
- 97
-
2nd Feb 2020, 08:47 PM #18Most Valued Member
- Join Date
- Oct 2010
- Location
- melbourne, laverton
- Posts
- 1,910
change gear
hi Chas. He al ways is. But thanks . I couldnt get a change gear calculator working on my phone. Ive forgotten how to do it.
Ray-s kindly offered me a 33 tooth hercus gear to use but im not even sure what combination i would use that in.
Plus tommie thanks for the info. I 1 or 2 gear cutters.
IMG_20200201_001803.jpg
here is another try to my photo. it says 20 dp No.2 14 1/5
From what ive read you cant get a 63 tooth gear out of a 40 to1 indexing head.
aaron
-
3rd Feb 2020, 07:12 AM #19Philomath in training
- Join Date
- Oct 2011
- Location
- Norwood-ish, Adelaide
- Age
- 59
- Posts
- 6,561
From what Tommy is saying, the gears are 18DP, so a 20DP cutter will not produce the correct tooth shape. It will be a no. 2, as they do 54 to 135 teeth.
You are correct that a 40:1 (semi-universal) dividing head will not do a 63 tooth gear. If you have a rotary table that can be set up with plates, I think that should be able to do it though.
Michael
-
24th Aug 2020, 11:36 PM #20Novice
- Join Date
- May 2012
- Location
- Hobart
- Posts
- 18
-
25th Aug 2020, 08:41 PM #21Senior Member
- Join Date
- Aug 2012
- Location
- Greenmount, W.A.
- Age
- 70
- Posts
- 275
From Harold Hall's website:
My metalworking and other interests. Harold Hall
I down loaded his tables. This page:
http://www.homews.co.uk/page30.html
From them is some examples:
CHANGEWHEEL COMBINATIONS
AND RESULTING THREADS PER
INCH FOR A LATHE WITH AN
8TPI IMPERIAL LEADSCREW
TPI R1 R2 R3 N1 N2 N3
16.9867 20 25 45 21 35 65
16.9867 20 30 75 21 65 70
16.9867 20 45 50 21 65 70
16.9867 20 50 75 35 65 70
16.9867 25 30 60 21 65 70
16.9867 25 40 45 21 65 70
16.9867 25 40 75 35 65 70
16.9867 25 50 60 35 65 70
17.0040 20 38 65 25 60 70
17.0040 20 38 65 30 50 70
17.0040 20 38 65 35 40 75
17.0040 20 38 65 35 50 60
17.0040 21 38 65 35 45 70
17.0040 25 38 65 35 50 75
17.0040 30 38 65 35 60 75
17.0040 30 38 65 45 50 70
17.0040 38 40 65 50 60 70
17.0040 38 65 70 75
Harold also explains the effect of errors......
Too complex for me! Read it yourself.
-
26th Aug 2020, 01:48 AM #22Most Valued Member
- Join Date
- Oct 2010
- Location
- melbourne, laverton
- Posts
- 1,910
thanks guys i havnt solved this problem yet so thanks.
-
26th Aug 2020, 10:37 PM #23
Vernon's program works for me on a PC -- never mastered the phone version either
Vernon provided a link to download the PC version originally and when I got a new PC he was kind enough to provide a copy again
Anyway from Lathegears I found
16 stud, 34 screw gear
24 stud, 51 screw gear
32 stud, 68 screw gear
?40 stud to 85 screw gear would also work
One is aiming for a reduction of of 2.125
On my Hercus the 100/127 will fit as an idler combination but do not expect to shut the cover.cheers
David
------------------------------------------------
A society grows great when old men plant trees whose shade they’ll never sit in. (Greek proverb)
-
27th Aug 2020, 12:57 AM #24
Hi Guys,
The Myford uses a 63 tooth gear. Although I understand a 127 tooth gear is available.Best Regards:
Baron J.
-
27th Aug 2020, 02:43 PM #25Novice
- Join Date
- May 2012
- Location
- Hobart
- Posts
- 18
Harold also explains the effect of errors......
Too complex for me!
[/QUOTE]
Agree, it looks complicated. Partly because of not eliminating "silly" gear options.
For example, cutting a 22.000 tpi thread the first option uses a 22T and 55T gears.
The next 16 gearing options use 6 gears - two of which are 22T and 55T. Why bother to include them?
... and a sample calculation would not hurt either (from the last example above - 8 x 40 x 55 x 75 / (20 x 50 x 75) = 22, or from the first example 8 x 55 / 20 = 22)
Similar Threads
-
why cant I cut this thread?
By Alf Scotting in forum METALWORK GENERALReplies: 47Last Post: 27th Oct 2018, 12:53 AM -
why cant I cut this thread?
By Alf Scotting in forum METALWORK GENERALReplies: 3Last Post: 8th Oct 2018, 08:00 PM -
WEST AUST All-thread Rod
By pmcgee in forum METALWORK - Machinery, Equipment, MARKETReplies: 0Last Post: 23rd Mar 2012, 09:48 PM -
This Thread Could Be About You!!!
By sydneyfc in forum FORUMS INFO, HELP, DISCUSSION & FEEDBACKReplies: 2Last Post: 28th Oct 2007, 09:39 PM