Needs Pictures: 0
Results 16 to 30 of 48
Thread: why cant I cut this thread?
-
8th Oct 2018, 08:27 PM #16Senior Member
- Join Date
- May 2015
- Location
- Richmond
- Posts
- 214
Hi Alf. This is in your opening lines "The thread chasing dial shows 24,21,20 and 18 and the appropriate alphabetical position to engage the dial - I cant understand why I cant engage anywhere as the sprocket engaging the leadscrew (24T) engages the fixed TPI leadscrew - does the fact that the chasing dial has only the numbers above mean I can only engage 24,21, 20 or 18 TPI? I am sure I haven't had this problem before so maybe I'm missing something?" Later you mention that it is in fact a metric leadscrew.
The relevance of the calcs was for the tracking problems which exist when cutting imperial on metric lathes and metric on imperial lathes. The 6mm leadscrew was just a sample. As you have two "threads" going on the same subject it starts to get confusing. Maybe better off locking that other one and continuing here.
To find why you are cutting around 40 tpi when it should be 16tpi you will have to give the full story. We now know that your leadscrew is 4mm but what gears are available and what is shown on a chart to convert a selected lead on your qc gearbox to cut a 1/16" lead. Until then, we are just guessing what the problem is.
Rusty
-
8th Oct 2018, 09:28 PM #17Most Valued Member
- Join Date
- Nov 2017
- Location
- Geelong, Australia
- Age
- 57
- Posts
- 2,672
Hi Alf,
This is the chart from mine. Is yours the same?
If I'm reading it right - mine would be 50 50 126 Gearbox #1 and B
IMG_3510 (Large).jpg
Steve
-
8th Oct 2018, 10:43 PM #18
-
9th Oct 2018, 06:42 AM #19Most Valued Member
- Join Date
- Nov 2007
- Location
- melbourne australia
- Posts
- 3,228
-
10th Oct 2018, 08:27 AM #20Senior Member
- Join Date
- Mar 2011
- Location
- Taree NSW
- Posts
- 119
Hi Rusty and gentlemen,
Attached photos are of the chartsimage006.jpg on my laimage004.jpgthe as proimage003.jpgmiseimage002.jpgd -still don't know where I am going wrongimage001.jpg
-
10th Oct 2018, 08:39 AM #21Most Valued Member
- Join Date
- Jun 2007
- Location
- sydney ( st marys )
- Age
- 64
- Posts
- 4,890
Your chasing dial and chart are not required, as said previously leave the half nuts engaged and just reverse.
Is the gear train set correctly.
-
10th Oct 2018, 11:10 AM #22Most Valued Member
- Join Date
- Nov 2017
- Location
- Geelong, Australia
- Age
- 57
- Posts
- 2,672
An earlier post stated that the gears were set to 72 68 30 120 so that would seem OK to me.
Its a later model than mine (which is 1987). Looks nice BTW
Getting 40tpi when set to cut 16tpi it almost seems like its in feed mode. From a general troubleshooting aspect, I'd suggest trying to cut something like 10tpi and see what happens and if there looks like a pattern (ie still roughly 3x too fine).
Steve
-
11th Oct 2018, 08:46 AM #23Senior Member
- Join Date
- Mar 2011
- Location
- Taree NSW
- Posts
- 119
yes, triple checked - I think I have found the problem ,will check after breakfast - the lever in image002 should be to the left?
will report back and hopefully close thread
-
11th Oct 2018, 09:58 AM #24Member
- Join Date
- Jul 2013
- Location
- BRISBANE BAYSIDE
- Posts
- 90
According to your chart, for imperial threads, both the levers in images 002 & 003 should be on the left.
-
12th Oct 2018, 12:37 PM #25Senior Member
- Join Date
- Mar 2011
- Location
- Taree NSW
- Posts
- 119
Tried that - no difference - I have sent off an email to Takisawa, let's see if we get an answer. maybe there is a problem with the gearbox?
-
12th Oct 2018, 03:09 PM #26Senior Member
- Join Date
- Dec 2013
- Location
- Sydney
- Posts
- 201
"No difference" This is a clue. Moving those levers should always lead to a different pitch. Are you sure you are not engaging the lever for feeds, instead of the half nuts for threading?
Graham.
-
13th Oct 2018, 07:07 PM #27Senior Member
- Join Date
- Mar 2011
- Location
- Taree NSW
- Posts
- 119
O.K. Rusty,
Have done your calc. relative to my lathe and have a result of 508 - what does that do for me and where did you get your 127 over 5 from?
have tried everything else even sent an email to Takisawa - let me have your ph. No. by private message and I will call you to discuss
Alf
-
13th Oct 2018, 07:09 PM #28Senior Member
- Join Date
- Mar 2011
- Location
- Taree NSW
- Posts
- 119
Not so - when I do that I can only get the traverse shaft rotating
-
13th Oct 2018, 07:12 PM #29Senior Member
- Join Date
- Mar 2011
- Location
- Taree NSW
- Posts
- 119
Not possible - there is a lockout on my lathe where you can't engage traverse when you are trying to cut threads
-
13th Oct 2018, 07:13 PM #30Senior Member
- Join Date
- Mar 2011
- Location
- Taree NSW
- Posts
- 119
If I do that only the traverse shaft rotates , not the leadscrew
Similar Threads
-
16 TPI thread
By BigStick in forum METALWORK GENERALReplies: 9Last Post: 3rd Dec 2015, 04:42 AM -
Best thread for All
By GSRocket in forum METALWORK GENERALReplies: 6Last Post: 11th Aug 2012, 05:02 PM -
Thread changes?
By oges in forum FORUMS INFO, HELP, DISCUSSION & FEEDBACKReplies: 3Last Post: 20th Nov 2004, 01:12 AM