Modernizing a Watchmakers Lathe

Brento

Registered User
Jan 23, 2021
86
7
8
28
Country
So i have a decent project coming up th is going to require to make a quantity of 7 parts for a total of 7 parts. I was thinking of using a dial indicator to mount onto the base of the lathe bed with a mag back. My issue is that the dial indicators are way to big. Do they make smaller indicators? If not then i will have to make a makeshift steel plate onto the wooden block the lathe is attached to to place a dial indicator.
 

karlmansson

Registered User
Apr 20, 2013
2,806
203
63
Linköping, Sweden
Country
Is it the indicators or the mag bases that are too large? They make both in different sizes.

Some make mounting brackets for indicators on slide ways that screw into the castings and keep the indicator parallel to the travel and keep the entire mount as small and out of the way as possible. The problem with smaller indicators is usually the travel. I have a 30mm travel indicator that is my largest and most often used for slideways but it is quite large and heavy. What many do is to use the indicator as a "stop" with early warning. You set it up as a reference on the ways but not to measure the entire travel.
 

Brento

Registered User
Jan 23, 2021
86
7
8
28
Country
Well both are big i can make it work if i remove the tailstock bc then it is put of the way. With it being a derbyshire i didnt think there are any adaptors to the ways to hold a indicator. I was going to use one of my 1" travel dials. Ive never seen smaller sized dials which is why i am asking here.
 

Brento

Registered User
Jan 23, 2021
86
7
8
28
Country
Id have to see what i can come up with. I think in the mean time i will fasten a bracket to the side of my wooden block.
 

karlmansson

Registered User
Apr 20, 2013
2,806
203
63
Linköping, Sweden
Country
Id have to see what i can come up with. I think in the mean time i will fasten a bracket to the side of my wooden block.
You want the fixture for the indicator to be as close to the fulcrum of the movement as possible to make sure you are not picking up any flex from the parts in between. This is especially true for wood. No point in using a 0,01 indicator if you are mounting it to a wooden base board of the lathe. Better to use calipers or even a precise ruler if your tolerances are not more critical than that.
 

bartmes

NAWCC Member
May 20, 2012
33
6
8
I own a Compac dial indicator that has a 1" dial. Compac ceased production last year but many are available on Ebay, both used and new. As Karlmansson rightly points out this size has limited travel. Another issue for some is the mounting stem is 8mm while most dial indicators sold here in the States have 3/8" stems. Not all stands can mount 8mm stems. That said, it is a beautifully made with the usual Swiss accuracy.
 

Brento

Registered User
Jan 23, 2021
86
7
8
28
Country
Well when you have a lathe you can make adaptors for these things lol. Thank you for your input.
 

wefalck

Registered User
Mar 29, 2011
713
89
28
Paris
Country
Are you talking actually about the type of indicator that measures the movement by a plunger that moves in and out or the type with a lever, that is used to test e.g. for run-out ?

The latter commonly seems to have dial of about 25 mm diameter. The bodies usually have dovetails on several faces to which stems screw. The stems typically have 8 mm diameter, but there are also 4 mm stems available.

The plunger type usually is mounted by a throat of 8 mm diameter below the dial. Today they normally have 50 mm diameter (if someone nows as source for 30 mm dials, I would like to hear ...) and have travels of 10 mm or 25 m. Therer are also version with longer travel, but they are even larger.

Another option for repetitve work could also be to fabricate stops for the slides. I have made two types myself: one type clamps to the dovetail of the slide and has a screw with lock-nut for fine adjustment in the body. The other clamps into the end of the whole for the spindle and also has an M3 screw for fine adjustment against which the top-slide runs. Here is a picture of the latter:

1621711146024.png
 

karlmansson

Registered User
Apr 20, 2013
2,806
203
63
Linköping, Sweden
Country
I agree that a stop is probably the easiest and most reliable solution for your situation. Fuss with measurements once and then just knock the parts out using fixed stops.
 

measuretwice

Registered User
Jul 28, 2019
118
39
28
Toronto
Country
I agree that a stop is probably the easiest and most reliable solution for your situation.
I've a Schaublin 70 set up for multiple parts, not a dial in sight...everything is based on stops and its a treat to use.....but for seven parts, rigging up an indicator might be faster than making lockable stop arrangements.

I like the idea of a steel plate mounted behind the lathe. Wood is not super stable and does change with temp and humidity, but my guess you'd see a good degree of repeatability during a session.

On bigger lathes, when a lot of accuracy is needed, I use a mitutoyo digital indicator clamped to the X axis that reads in microns/tenths. Its so convenient I've never much felt the need for a DRO on a lathe.
 

wefalck

Registered User
Mar 29, 2011
713
89
28
Paris
Country
Fitting analogue read-out dials to a watchmakers lathe is rather awkward, when you have both, long and short parts to deal with. Some high-end manufacturers in past, however, offered attachment kits to convert their lathes for turning hard contact lenses. To this end all slides (and a radius turning fixture) were fitted with dial indicators. Typically brackets that hold the stems of the indicators are screwed to the slides. Just search on Google for 'optical lathe' for pictures of such arrangements.

1621950999580.png
Picture from www.lathes.co.uk
 

Brento

Registered User
Jan 23, 2021
86
7
8
28
Country
What i am thinking of doing is drilling into the wood block with a steel plate to attach the stand to.
 

Brento

Registered User
Jan 23, 2021
86
7
8
28
Country
I've a Schaublin 70 set up for multiple parts, not a dial in sight...everything is based on stops and its a treat to use.....but for seven parts, rigging up an indicator might be faster than making lockable stop arrangements.

I like the idea of a steel plate mounted behind the lathe. Wood is not super stable and does change with temp and humidity, but my guess you'd see a good degree of repeatability during a session.

On bigger lathes, when a lot of accuracy is needed, I use a mitutoyo digital indicator clamped to the X axis that reads in microns/tenths. Its so convenient I've never much felt the need for a DRO on a lathe.
i am thinking of attaching a metal plate to the wood block the lathe is bolted to so i can put a mag base on it.
 

karlmansson

Registered User
Apr 20, 2013
2,806
203
63
Linköping, Sweden
Country
A metal plate that both the lathe and magbase is mounted to would be the bare minimum in my opinion. Try leaning just a little bit on the board with an indicator mounted on a heavy, metal object standing on it and look at the deflection.
 

Brento

Registered User
Jan 23, 2021
86
7
8
28
Country
Yea im sure it wont be perfect i am also trying to set up so i can indicate the 4 jaw in.
 

measuretwice

Registered User
Jul 28, 2019
118
39
28
Toronto
Country
i am thinking of attaching a metal plate to the wood block the lathe is bolted to so i can put a mag base on it.
thats what I'd try just because its so easy to do. We're into the grey a bit. I think what Karl is saying is correct and its not the ideal production set up but I also think its doable and repeatable to make 7. We're into the grey; there is going to be a big difference between a base of sealed 2" hard maple or 1/2" of soggy particle board/MDF etc.

Two things with wood, its not dimensionally stable so changes with humitdy. temp etc. That is somewhat controlled if its a sealed and is not a factor for 7 parts in done at a time - i.e. no change environment affecting the wood. Secondlly wood is more flexibe - how it reacts to an applied force. This is also grey as performance will depend on how sturdy the base is and what if any external forces are forces are applied. Wood has a much lower modulus of elasticity than steel or cast iron, but also has a much lower density - i.e. you can make up for its great flexilibty by using more of it and pound for pound a good hardwood performs well.

Bottom line, my view is this has a better chance of working with a heavy hardwood base and avoidng extraneous forces leaning on (For matter, you can change cut on larger lathe by leaning on it) but depending the base should be ok, or at least worth a try. Keep us posted
 

Brento

Registered User
Jan 23, 2021
86
7
8
28
Country
Thats the size board that i would bolt into. I plan to rest it on the table as well to help stability.

09B816F7-9A39-42F9-97FB-F1F05EBC6925.jpeg
 

wefalck

Registered User
Mar 29, 2011
713
89
28
Paris
Country
An off-topic question: is the cross-slide put together correctly ? I am rather surprised to see a ball-crank on the taper-turning top-slide, while there is a knurled knob on the longitudinal slide.

Personally, I am not so fond of having magnetic thingies on my machines. Somehow they magnetise some parts and also attract swarf themselves.
 
Last edited:

Brento

Registered User
Jan 23, 2021
86
7
8
28
Country
My mag base isnt small which is the issue. Plus as i said prior i was thinking of using the mag base to hold onto a drop indicator for length dimensions.
 

Forum statistics

Threads
167,092
Messages
1,456,076
Members
87,298
Latest member
Samways
Encyclopedia Pages
1,057
Total wiki contributions
2,914
Last edit
E. Howard & Co. by Clint Geller