[4]

Thread dial indicator.

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

Suzuki4evr

Active Member
Registered
Joined
Sep 29, 2017
Messages
380
Likes
389
#1
Hey chippers
Is there something on this site about making your own thread dial indicator for metric and imperial threading. I can't seem to find any,maybe looking in the wrong place. I have a metric Mashstroy lathe with the thread dial indicator missing. I've been threading without it for very long time now, but it is taking to long when doing long threads. Any help would be appreciated.

Michael
 

4ssss

Active Member
Registered
Joined
Apr 25, 2017
Messages
440
Likes
252
#2
You don't need a thread dial. When you cut threads, pull the tool out at the end of the thread, reverse the motor without disconnecting the split nut, at the beginning of the thread, reverse the motor again and cut another pass. It may sound like a pain, but it's faster than you think when you don't have a dial
 

RJSakowski

H-M Supporter - Gold Member
H-M Supporter - Gold Member ($25)
Joined
Feb 1, 2015
Messages
3,510
Likes
4,036
#3
I made a new thread dial for my Grizzly lathe but not the axle and gear. The first step is to determine the lead of the lead screw on inches/ thread if Imperial or mm/thread if metric. Most Imperial lead screws are either 8 tpi (.125" lead) or 16 tpi (.0625" lead). Your mating gear has to have the same pitch to mesh with the lead screw. Some gears are cut with helical teeth to match the helix of the lead screw but another common technique is to rotate the axis slightly to mesh so an ordinary spur gear can be used. There is no load involved so you can get away with a less than perfect mesh.

Normally, the gear would have four times as many teeth as as are in one inch of the lead screw for and Imperial setup. This means that the thread dial makes on complete revolution for four inches of carriage travel. The dial then has four numbered marks and four in-between marks. My Grizzly is an exception as the lead screw has 12 threads/inch and 36 teeth on the gear, making a complete revolution in three inches. It has 12 markes on the dial. Metric lead screws & thread dials work in a similar fashion.

The difficult part would be finding/making the gear. A little searching, once you know the diametral pitch, should turn up a suitable gear. An axle and housing would have to be made as well as a thread dial. It is possible that you might be able to find an assembly from another lathe that could be modified to fit yours.

edit: re-reading your post, I see that the lathe is metric. The procedure is the same though. SPI has low cost metric gears which will work for you. http://www.sdp-si.com/products/Gears/Index.php
 

Suzuki4evr

Active Member
Registered
Joined
Sep 29, 2017
Messages
380
Likes
389
#4
You don't need a thread dial. When you cut threads, pull the tool out at the end of the thread, reverse the motor without disconnecting the split nut, at the beginning of the thread, reverse the motor again and cut another pass. It may sound like a pain, but it's faster than you think when you don't have a dial
Thank you,but I know this and this is how I've been doing it,but like I said,when I do long threads it takes to long for my taste, but thanks for the input
 

plunger

New Member
Registered
Joined
Jun 1, 2018
Messages
20
Likes
14
#5
I dont think it would be too difficult to knock up a brass gear for your leadscrew. As has been pointed out it doesnt have to be exact. Im sure a flycutter could do it.
 

BaronJ

Brass
Registered
Joined
Aug 7, 2018
Messages
508
Likes
256
#6
Hi Guys,

I've rescued loads of gears, most of them plastic, from old printers, photocopiers etc. Its possible you might get a suitable gear that way.
 

P. Waller

H-M Supporter - Sustaining Member
H-M Platinum Supporter ($50)
Joined
Mar 10, 2018
Messages
519
Likes
337
#7
Thank you,but I know this and this is how I've been doing it,but like I said,when I do long threads it takes to long for my taste, but thanks for the input
If speed is your #1 CONCERN then buy a NC lathe, input the start Z and the end Z, start diameter and finish diameter and the lead, this can be either metric or inch, it does not matter as lead is lead regardless of units.
 

9t8z28

Active Member
Registered
Joined
Aug 16, 2016
Messages
213
Likes
82
#8
I have thought about doing this as well and wondered what was involved. Great info RJSakowski. I don’t see an NC lathe as a solution. Sorry but its not what he’s wanting or asking.
 

9t8z28

Active Member
Registered
Joined
Aug 16, 2016
Messages
213
Likes
82
#9
Me too. I’ve got buckets full of printer gears! I am amazed at the quality and design of some of them, especially the brass worm gears. One day I’ll make up a powerfeed or something cool with some of these gears.
Hi Guys,

I've rescued loads of gears, most of them plastic, from old printers, photocopiers etc. Its possible you might get a suitable gear that way.
 

plunger

New Member
Registered
Joined
Jun 1, 2018
Messages
20
Likes
14
#10
Michael I once asked the very same question that you asked . I recieved a pm and a guy in JHB who is very talented had the same lathe as me EMCO v13. He built me one for free .But looking at it ,theres not much to it.
Do you have a manual for this lathe because it may take the guesswork out of the size and teeth on the gear.
Heres mine. He didnt have no stamps so just colour coded the dial.
 

hman

Active User
H-M Platinum Supporter ($50)
Joined
Feb 17, 2013
Messages
1,752
Likes
1,369
#12
Issue #271 of Model Engineers' Workshop (September 2018) includes an article entitled "Making a Threading Indicator for a Lathe." It's on pages 58 thru 63 and continues/concludes in issue #272 (Autumn Special 2018), pages 67 thru 69. It goes into great detail, including the required parameters for both Imperial and metric (2 thru 6mm pitch) leadscrews. I have no idea how easy it it for you to get publications from the UK where you are. If need be, PM me and I can scan and email the pages to you.
 

ttabbal

H-M Supporter - Silver Member
H-M Supporter - Silver Member ($10)
Joined
Jun 12, 2017
Messages
661
Likes
658
#13
If you scan them, I'd be interested in reading it.
 

Tozguy

Active User
H-M Supporter - Gold Member ($25)
Joined
Feb 15, 2013
Messages
1,676
Likes
1,096
#14
plunger, re the picture above, just curious about how you get the gear to mesh with the lead screw.
 

Suzuki4evr

Active Member
Registered
Joined
Sep 29, 2017
Messages
380
Likes
389
#15
If speed is your #1 CONCERN then buy a NC lathe, input the start Z and the end Z, start diameter and finish diameter and the lead, this can be either metric or inch, it does not matter as lead is lead regardless of units.
I don't really have money laying around to go and buy new lathes to solve one problem. But if I did have the money, that is probably an option, but I want to solve my problem the cheapest way possible and that is to make an indicator, because buying is also an issue, because I can't get one for my model lathe.
 

Suzuki4evr

Active Member
Registered
Joined
Sep 29, 2017
Messages
380
Likes
389
#16
D
Michael I once asked the very same question that you asked . I recieved a pm and a guy in JHB who is very talented had the same lathe as me EMCO v13. He built me one for free .But looking at it ,theres not much to it.
Do you have a manual for this lathe because it may take the guesswork out of the size and teeth on the gear.
Heres mine. He didnt have no stamps so just colour coded the dial.
I don't see it in my manual,some pages nissing and you can't find this lathe model on the Internet.
 

Suzuki4evr

Active Member
Registered
Joined
Sep 29, 2017
Messages
380
Likes
389
#17
plunger, re the picture above, just curious about how you get the gear to mesh with the lead screw.
So am I,it looks kinda out of alignment.
 

plunger

New Member
Registered
Joined
Jun 1, 2018
Messages
20
Likes
14
#18
The photo is taken from underneath.It simply rotates untill it makes contact.I only use it for odd threads like 1,25 and 1,75 mm. My pitch is 6mm and for imperial of which I do alot I never disingauge the half nut.
 

bhigdog

Active Member
Registered
Joined
Apr 29, 2018
Messages
51
Likes
109
#19
I made a new gear out of brass for my LeBlond. Pretty easy with a spin fixture and a home made cutter. You could even use a one tooth fly cutter type cutter. Click on the pix for full size........Bob
 

Attachments

Last edited:

KMoffett

Active User
H-M Supporter - Silver Member ($10)
Joined
Jan 18, 2013
Messages
391
Likes
111
#20
I had a South Bend lathe without a thread dial. I was lucky enough to order and receive a thread dial gear from South Bend...just as they were closing the door. Body out of aluminum tube. Mount from a slit steel pipe, with a pin that fit the apron welded to it.

Ken

T_DIAL1.jpg T_DIAL2.jpg
 

Tozguy

Active User
H-M Supporter - Gold Member ($25)
Joined
Feb 15, 2013
Messages
1,676
Likes
1,096
#21
D

I don't see it in my manual,some pages nissing and you can't find this lathe model on the Internet.
Suzuki, if you provide us with the exact thread spec of your lead screw, then the thread dial gear from any lathe with the same lead screw should work. Maybe we could provide you with the part number and source for a gear only and you could make the other parts to use that gear on your lathe. Unfortunately my lead screw is inchy or I would provide you with that information.

And as RJ mentioned above in all likelihood it would be rather simple to fit a whole thread dial from another metric lathe with the same lead screw.
 

Suzuki4evr

Active Member
Registered
Joined
Sep 29, 2017
Messages
380
Likes
389
#22
Suzuki, if you provide us with the exact thread spec of your lead screw, then the thread dial gear from any lathe with the same lead screw should work. Maybe we could provide you with the part number and source for a gear only and you could make the other parts to use that gear on your lathe. Unfortunately my lead screw is inchy or I would provide you with that information.

And as RJ mentioned above in all likelihood it would be rather simple to fit a whole thread dial from another metric lathe with the same lead screw.
I am trying to figure that out now. I have a thread gauge, but it only goes up to 5.5mm. This leadscrew has a very strang pitch. My caliper is set on 25.4mm (1'), as you can see,but the thread does not seem to be imperial.
20181011_153325.jpg
The nominal size is 40mm and the minor size is 27mm. So does this mean it is a 40×13 leadscrew or do I have it totally wrong?
20181011_152930.jpg
20181011_153010.jpg
I found the diagram in the manual.This is the diagram out of the manual,but it does not say anywhere the leadscrew pitch or the size of the gear and other thingI do not understand is the clock section on when to engage the halfnut on wich number for wich pitch. Can you declare this maybe.
IMG-20181011-WA0010.jpg
 

Tozguy

Active User
H-M Supporter - Gold Member ($25)
Joined
Feb 15, 2013
Messages
1,676
Likes
1,096
#23
Another way to measure the pitch is with a metric ruler. Measure the length of 10 threads and divide by 10.
That is a strange thread tho.
 

plunger

New Member
Registered
Joined
Jun 1, 2018
Messages
20
Likes
14
#24
Its a bulgarian lathe?Would it not be metric.2,5mm?
 

bhigdog

Active Member
Registered
Joined
Apr 29, 2018
Messages
51
Likes
109
#25
Something wrong here. I can see a half nut engaging with that shaft but I can't see a smallish thread dial gear doing it. One tooth would almost be disengaged before the next engaged...........Bob
 

Tozguy

Active User
H-M Supporter - Gold Member ($25)
Joined
Feb 15, 2013
Messages
1,676
Likes
1,096
#26
So does this mean it is a 40×13 leadscrew or do I have it totally wrong?
I agree and would call it a 40x13mm thread also.
Based on the drawing of the thread dial that you provided above, the gear looks rather large and the lead screw threads are deep. Just eyeballing it, a gear with 25 teeth would mesh with the lead screw and would only be approx. 100 mm or 4'' in diameter. Hopefully sharper minds will be along to shed more light.
 

Tozguy

Active User
H-M Supporter - Gold Member ($25)
Joined
Feb 15, 2013
Messages
1,676
Likes
1,096
#27
The latter part of this video shows a neat homemade metric thread dial.
 

Suzuki4evr

Active Member
Registered
Joined
Sep 29, 2017
Messages
380
Likes
389
#28
Its a bulgarian lathe?Would it not be metric.2,5mm?
It looks to big for 2.5mn,but I am going out to the shop in a while and try to figure it out again.
 

Suzuki4evr

Active Member
Registered
Joined
Sep 29, 2017
Messages
380
Likes
389
#29
Ok guys I have looked it up now. When measuring metric threads,you measure it in threads per millimeter from credt to crest,but on the ACME thread or trapezoidal thread,you woul measure and what I have concluded now,it seems that the leadscrew I have is then a 40×12mm leadscrew. I think this looks like a reasonable conclusion. But like Tozguy said,it is a large and very deep pitch. What do you guys think of my conclusion and the big question is what size OD must the gear be for this? I know now I must have a 15T and 14T gear to cover the metric spectrum.
20181012_085508.jpg
 

Tozguy

Active User
H-M Supporter - Gold Member ($25)
Joined
Feb 15, 2013
Messages
1,676
Likes
1,096
#30
To get a more accurate reading with your caliper, open the caliper out and measure as many threads as possible. Then divide that length by the number of threads in your measurement. Be aware that the result does not have to be a round number, it could be 12.5mm for example.
I am no gear expert but to get the circumference of a 15T gear to match your lead screw just measure the length of 15 threads on the screw, then divide that number by pi (3.1416). For the 14T gear measure 14 threads on the screw. That will give you a ballpark diameter for the gear.
How did you determine that a 14 and 15 tooth gear is required?
 
[6]
[5] [7]
Top