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Discussion in 'Clock Repair' started by MuensterMann, Sep 27, 2019.
What are the typical broach sizes needed for clock winding arbors? Thanks!
I use the reamer in my bushing machine that matches the OD of the bushing I plan to use. I don’t think I have a broach that large.
The reamer will take care of the outer diameter, but I am thinking a broach is need to share and/or size the inner diameter.
You are right, MM. I have some that size, but not big enough for the OD.
I use my big lathe and boring bar to fit bushings to spring barrels. I have recently purchased a sherline mill and rotary table that I plan on setting up for that when I get time.
I think bushing a spring barrel by hand wont work because you first have to round up that oval shaped hole very precisely before fitting the bushing and then you have to open up the bushing to fit the arbor. There is no room for error.
I have this set and they seem to fit most winding arbors.
4-Piece x-Large Cutting Broach Set For Winding Arbor Bushings .2755" - .413"
John, I have a Sherline mill and rotary table also and am learning how to use it. I would love to see your set-up when you get it done. You are right about the “no room for error”.
I use this 4-Piece x-Large Cutting Broach Set For Winding Arbor Bushings .2755" - .413" also Works well Make sure the taper is okay had to send back my first set
Here is a set up using the Sherline lathe for a cap...
It should be noted that a broach will take the path of least resistance and will not assure that a broached hole is in the center a barrel or its cover, as others have also indicated. This of course can cause proper operation issues.
When repairing anything, I personally strive to make all repair work invisible.
To accomplish this with barrels and lids, I generally do the work as follows.
(1) I mount the barrel and or lid in the Lathe per first photo and bore just enough to clean up the hole and remove any wear.
(2) I then machine the bearing surfaces on the winding arbor about .025" smaller than original and leave a rough surface. Second photo
(3) I then machine a tight friction fit thick walled sleeve to fit the arbor. Actually I machine the sleeve first then the arbor to fit the sleeve. Again second photo.
(4) The sleeve is then easily driven on the arbor because of its large size and then machined down to a the desired size to either the barrel or lid.
No visible repair can be seen on either the barrel or lid and both are returned to original function.
Thanks for the info and photos, Vernon and Jerry. They are so helpful to me as I learn how to set up my jobs.
Jerry K. described his procedure in a similar, recent post. Recently I encountered a time & strike clock with excessive wear on both spring barrels and their caps. I implemented Jerry's technique and I was very pleased with the results. As he noted this is an invisible repair.
The only difference in my approach is I used an independent 4 jaw chuck because the barrels, caps, and arbors centers weren't true.
I guess a bushing machine is not used because it is not easy to hold the item fixed. And, perhaps that standard bushings (e.g. KWM) are not sized for a barrel. Is that correct?
A lathe is being used because it holds the barrel or lid - and it hold it such that it is centered. Is that correct?
Okay, I am not a lathe user, although I do have an old one - Peerless. Can the old lathes be used for this, or is a Sherline a better one?
Thanks! I do bushings on the plates, but never did a barrel before. Seems like an important skill to learn!
The Peerless you have is a jewelers lathe which uses small collets, right? It is not equipped to hold anything as large as a barrel. Jerry’s photo in post #10 is using a Sherline. They are perfect for clock work. As far as using bushings goes, I have KWM bushings that fit those larger arbors and reamers that fit the OD of the specific bushing. And, yes, holding the barrel in the bushing machine is a problem. I have successfully reamed barrels and caps using a hand bushing tool, mounting the barrell in a vise. Once you ream it, the bushing can be pressed in with a bushing machine, a vise, or by using a brass or other soft headed hammer.
Yes, it is a jewelers lathe. I have collets but I know they have Jacobs chucks to fit it - but not sure if it opens up wide enough to grasp a barrel.
So, there are KWM bushing for barrels and caps? Hmmmm. And, you can hand bush them?? The largest KWM bushing shown on my pivot gauge is 4.8mm. Not sure if that is big enough, but I can check.
Yes. I used 8.7 mm. diameter bushings and the hole in most Hermle barrels is around 7.2 mm. The largest reamer I have is 5.85 mm. so I cut it to 5.85 with the hand bushing tool and carefully filed it with a rounded file to fit the 8.7 bushing. I am learning how to cut the holes with my Sherline now.
I always solder then bushing barrels.
There SO much presser on the bushings,
I have had success with loctite.
Sherline mill set up for bushing barrels and caps. This is just my first attempt at using my mill for this purpose and I used brass washers as bushings just to learn.
What a great piece of equipment.
Thanks John. Great photos. This helps me know where to begin as I set up my mill for this job. So, how much smaller is the hole than the OD of the bushing? Will the bushing snap in tightly enough that you don’t have to use loctite or solder?
I personally prefer to do the bushing of barrels on a lathe. I believe it is more straight forward. Use a boring bar to open and center the hole in the barrel to be bushed and machine a sleeve with an OD for a press fit in the new hole and an ID very slightly larger then the arbor (after filing and polishing the arbor as needed).
You use a three jaw chuck for the barrell or a four jaw? How about the cap? How do you set it up?
I don't have a four jaw chuck. I use a three jaw chuck for the barrel and cap, with the jaws turned around so that the flatter end will hold the work. If I had a four jaw chuck I would probably use it because it will hold the work more secure. I have machined a slight groove into the jaws close to the body of the chuck and at the beginning of each step so that the caps will not slip out to the front while turning.
Sherline has instructions how to reverse the jaws because they need to be in a specific order.
It sounds like I should be looking for a Sherline unit and learning how to operate it to perform more clock repair tasks. A jewelers lathe, I guess, cannot be used for barrel repairs. I wonder if hand bushing will work in my case with the barrels. If I invest in Sherline, I will be wondering to invest in lathe or mill!!!
WOW, I try to fit the bushings tight into the barrels but you have to sneak up on it and keep checking the bushing/ hole clearance. When they just start into the hole or even look like they will go, I pound them in. A bit of red lock tight is a good idea.
They can be a bit proud but the mill does an excellent job of cleaning that up. Start with some old hermle barrels and get some experience first.
The reason I am going to all this expense is because French and ships clocks with small barrels with lots of wear cannot be done on a large lathe and keep the accuracy that is needed. The mill and rotary table is spot on and perfect accuracy is easy to maintain.
You can if you have a jaw chuck that will accommodate barrels and caps. There are bench lathes other than sherline that you can buy for less money and do just as good a job. I have a Wade made in 1950's Has about 150 collets and a 2 -3 jaw 3' 4' chucks and cut away collets Paid 1500.00 on a bench Just get out there and look you can find deals.
It should be noted for beginners, While there are exceptions, unless you are highly experienced in machine tools, bargains more often than not become projects themselves rather than tools to do projects.
I am familiar with Wade tools and at one time owned a No.3 Lathe. What model do you have out of curiosity ?
I would definitely like to receive instruction before buying and using a lathe/mill. I am thinking of a NAWCC course, but the one Sherline one that is coming up is already full. Hopefully there are others!
From what I understand The NAWCC school closed. Unless a local chapter is holding classes
The School actually never closed.
While they no longer offer the one and two year courses in watchmaking and clock repair of the past, they do offer a wide range of one week or less specialized workshops.
These work shops cover horological repair subjects that includes Lathe and milling machine classes. The watchmaker Lathe class utilizes a watchmakers Lathe for watch work only.
The Micro Lathe class utilizes Sherline Lathes and covers Micro machining that includes both watch (And smaller) as well as Clock size work.
Class schedule can be found under NAWCC Education and then Workshops. While there are only 5 courses listed at this time because its the end of the year, when the 2020 schedule is listed there will probably be as many as 20-30 options.
Where is the Jewelers lathe course for clocks
While it may be serious for some and far less so for others, it is again something that should be clarified for beginners who may read this.
In the mid 1850`s watchmakers lathes appeared something like the one in the first photo. As industry started manufacturing watches, it quickly evolved into what is commonly seen today in the second photo. It was designed for and commonly used by watchmakers to ever so slightly adjust replacement watch parts for fitting. It was practical for this type work since it only required a lathe, collets and the ability to master a Graver.
However, Clock repair publications often refer to the use of the Watchmakers lathes in clock repair since at the time of publication, they were one of the very few options commonly familiar to Horologist at the time.
Again however, in todays world there are readily available options that are far more efficient and capable of clock size work.
I do a lot of my clock work with a jewelers lathe. I'm not promoting it, it's a matter of fact. No one pays me to be here I do this for free.
If by chance you start doing clock work for free, let me know.
Give me a free Shirline lathe complete with everything as a promotion stunt. They'll understand