Homemade Pivot Lathe/Polisher

[ddhix]

So I built a "pivot lathe"/polisher today out of a door hinge.

Here is the video of the operation:

[video=youtube;RTH5lk-uKoY]http://www.youtube.com/watch?v=RTH5lk-uKoY[/video]

The pictures are mixed up, and I don't know how to organize them. At the end of this is a list of what each picture is.

Okay, so it really wasn't that hard. There are a couple of things, though. First, I would rather have not used wood dowel. I only bought the wood dowel because the hardware store did not have 5/16ths brass rod. I'll be ordering some brass rod soon, so I can have more reliable rests. Also, I didn't know this, but there are two different qualities of wood dowel; I bought the cheap quality, not thinking about the hardness of the wood when I bought it (I just thought about saving a buck). So while I'm waiting to order the brass rod, I'll run back to the hardware store and spend a few extra dollars on the better wood dowel, so it will be more resistant to cracking when drilling it out.

If anyone is curious, the inside diameter of the hinge, where the hinge pin goes, is 5/16".

The best part of this is when I hooked the spring up to the bench, and ran the fishing line to it. I found that wrapping the fishing line around the arbor twice is best for a solid movement without any slipping. It works so fluidly I was really surprised. I honestly thought I would be struggling with learning how to move properly to make it work. Using a spring is hundreds of times better than using the bow! Also, if anyone is curious, the spring I used was the skinny long spring. I read somewhere here that someone used a door spring, but I really felt like that was way too strong. I used the one that had a good amount of soft, lengthy stretch to it, as to prevent any undue pressure on the pivots while on the resting points.

Also, I'll be adding one more tightening screw to the right and left rests. They'll be located on the sides, as to prevent any side-to-side motion (I noticed some).

Finally, does anyone have any recommendations? I am really proud of my ugly little tool here, and am excited that I haven't paid a ton for a professional tool. I'd like to make it better.

Oh! And please excuse my work bench. Its usually very clean and fairly organized. But with this kind of work, I was shuffling around a lot and kindof throwing things around here and there, making a mess of things.

Pic 1 is the cutting wheel I got.

Pic 2 is what was revealed when cutting into the door hinge. I stopped cutting here because I didn't want one of those ball bearings to sling out like a bullet.

Pic 3 is after cutting everytihng away to make space for the gear

Pic 4 is teaching my kid how to use a drill press

Pic 5 is the hinge after removing the other side of it

Pic 6 is the 5/16ths wood dowel I bought

Pic 7 is the hinge after cutting away

Pic 8 is the preliminary cuts into the hinge to cut away space

Pic 9 using a punch to get that hinge pin end out

Pic 10 is which hinge I bought (at Lowes), in case anyone wanted to use the same one

Pic 11 is drilling for the tightening bolts

Pic 12 is the same thing

Pic 13 is tapping the hole for the tightening bolt

Pic 14 is first setting up to see how it came together

Pic 15 is the bow, which is a coat hanger with 25lb fishing line wrapped once around the arbor

Pic 16 is the springs I bought (for better operation), in case anyone wanted to use the same one.

Pic 17 is one of the rests I made out of the wood dowel

 

[shimmystep]

Nice job ddhix.
Excuse the work bench he says. I was watching the video thinking "tidy work bench".

 

[harold bain]

Have a look at this thread. You will find a few helpful hints for improvements there:
https://mb.nawcc.org/showthread.php?18707-Pivot-polisher/page2&highlight=pivot polisher

 

[bangster]

Cool pix! And good job.

Remember: "A tidy workbench is a sign of a sick mind."

 

[tom427cid]

Imagineering-Bravo,job well done
tom

 

[David S]

Wow lots of great pictures. And I really like how you did the prototype. I sure understand working with prototype materials and then converting to more robust ones, once the bugs are worked out.. Good job and thanks for sharing.

 

[lirenrui]

good job!

I also have done a pivot polisher,
It can also be use for mainspring winder.
Black is the governor.

li renrui

 

[R&A]

I am into building things and all. And safety should always come first. So I suggest you provide your young helper there, with some safety glasses. What powers this is hard for me to understand. But very inventive. Be careful on wobble and out of true. It will oblong your pivots.

H/V

 

[R&A]

good job!

I also have done a pivot polisher,
It can also be use for mainspring winder.
Black is the governor.

li renrui

With that metal brace. How do you keep it from cutting a grove into the pivot surface? I would suggest using a softer material that is adjustable for different sizes. And rest the arbor on the brace.

H/C

 

[MARK A. BUTTERWORTH]

Very inventive. We have an intro kit of carbide impregnated disk and a mandrel for doing the actual polishing that is dirt cheap and makes the job very quite. It is on you tube and key butterworth1725

 

[Walesey]

Must be time for me to drop my 2 cents worth in!!

Very impressive, ddhix. I have read about hinge based pivot turns, and even went out and bought myself a couple of hinges to do a similar job myself, just haven't got a round tuit. Thanks for all the photos. They show well all the steps. Actually besides the round tuit, I do not have a lot of tools to help me either, so that has slowed me down a bit.

About a month ago, at my monday night clock repair group that I attend, the leader (Doug Minty) showed us a home made tool very similar to this one.



I guess there is no copyright, as a plan for the same device were published last week in the Chapter 72 newsletter, although I had made mine up from a photo that I took before I got the newsletter with the plans, so my dimensions will differ from the published plans.

It is made out of three bits of wood, held together by coach bolts and wing nuts, so it is adjustable for any length arbour. The spring is one of those very loose, floppy springs. It's only purpose really is to return the string to the starting position, without putting too much downwards force on the pivots. The string is just braided nylon, although Doug Minty's was rubberised, which would give a better grip. As the pivots are supported at both ends, (cradled in the groove filed in to the top of the vertical legs), it allows me to do those pivots where the wheel or pinion is right down one end of the arbour. Those wheels are sometimes hard to hold in a lathe (but I don't have a lathe any way! I have used a drill press, tipped on to it's side, on my bench, but this home made polisher works better for those difficult wheels)

The best part about it was that I could make it without any fancy equipment, from scrap wood I had around the shed. I even had the coach bolts and wing nuts in a drawer.

I will try to add some YouTube videos to show how it works

[video=youtube;IFQvTMXtCGk]http://www.youtube.com/watch?v=IFQvTMXtCGk[/video]

Mark, I used your polishing disks. They worked very well with this set up. I tried to add a video to demonstrate, but the system will only allow one video per post!

There you go. My 2c worth!

Walesey

 

[Walesey]

I will see if I can get a video showing my polisher in action here!

[video=youtube;q3I9td5VsX4]http://www.youtube.com/watch?v=q3I9td5VsX4[/video]

OK. How's that?

I am using my home made Pivot Polisher (as described in a previous post) with the polishing disks sold by Mark Butterfield. The mandrill is held in a cheap imitation of a "Dremel". But it works well for it's purpose!

Cheers

Walesey

 

[lirenrui]

With that metal brace. How do you keep it from cutting a grove into the pivot surface? I would suggest using a softer material that is adjustable for different sizes. And rest the arbor on the brace.

H/C

This photo can explain the question.

 

[Charles E. Davis]

It is interesting to see different approaches to pivot polishing.
I have been served well by the units I made from hinges first in 1979 when I taught my first class and I needed to add to the equipment I had been using for my first dozen years. It was the old fashioned turns that I had found in a local swap meet. The ones I first made are still being used by the local adult ed class that I was asked to teach over 30 years ago.
I have made many of them of them since and recently send one to England. One of my Japanese friends also has one.
As I outlined in earlier threads on pivot polishing, I have made some changes but the ones made from the three section hinge side still has the same appearance. I try to cut only as much as needed from the hinge and am careful to avoid the edges of screw holes. Slanted sides also give a little more support and weight to the hinge. (One of my earlier failures was making one out of aluminum hinge!)
Another change from that is not using a bushing to reduce the holes to the runner sizes. I always used metal bushings that were pressure fit into the hole for the hinge pin. And I have always made the runners out of the same diameter brass rod that matched my stakes that fit in the turns. Now instead of a bushing I pack the hole with JB Weld and line drill the hole for the runners with a long enough drill to assure correct alignment. This change was forced on me when I was given an assortment of heavy duty hinges that used special sleeves that were inserted in the ends of the holes. I had to drill the hinge out to a uniform size and I wasn't very good at that! Now I make a small hole in the center of the JB Weld in the outer ends. Then put a short drill, smaller than the runners, in the chuck of the lathe and support one end of the hinge on the tail stock center and drill the first end. Then reverse the hinge to drill the other end. I enlarge to hole to the proper size with a longer drill with the same set up in the lathe. I move the tailstock to give pressure for the drilling and at the last when almost to touch the center, finish the hole pushing with my hands. Actually I always use my hand to "float" the hinge between the drill and the center in the tail stock while drilling.
A third suggestion is to drill and tap the dowel bushing while you are doing it in the hings. Make your brass runners long enough to handle the adjustments needed but the dowel only needs to be the length of the hole in the hinge. I have never had any problem with side motion in the runners with this approach.
From the beginning I have never felt comfortable with a bow and early adopted a rubber squeegee. My latest version is a thin block of wood. The thickness of the saw blade makes a slot used to slip a strip of rubber into. I hold it with the old Swingline stapler used with paper. Two on both sides is adequate and they are too short to go out the other side. A squeegee is immediately available without the hassle of winding a string plus it gives and additional pressure down to hold the pivot in the runner. The grip is comfortable for both hands and you always know the relationship of the blade and the arbor.
Enough for now. I need to get some photos together on how I use the other half of the hinge to make an even superior modern replacement for the old time watch and clockmaker's critical tool tool.

 

[shimmystep]

Good to hear from you Charles. Vote of confidence from England for your pivot polisher, works very well. Look forward to seeing the other half of the hinge you speak of.

 

[R&A]

This photo can explain the question.

How do you keep it from cutting a grove into the arbor?? And how do you displace the heat form not turning the material blue. Or work hardening the material.

H/C

 

[Charles E. Davis]

Thanks for those good words from shimmystep. You ask about the other polisher that I make. I shipped the lightest unit to you for obvious reasons.
I am posting four photos and I hope I can get them in this order, If not they will be obvious when you see them.
No. 1 is the original pivot made from the three hole edge as the first prototype that I made. It has metal bushings and the box screw used to tighten the runners. (I was given a huge box of these and except for shortening them, they have worked out well.) As I mentioned in a previous message I have shifted to using JB Weld instead of the metal bushings. By line drilling the two holes I get a more consistent alignment. Of course one advantage of the dead center lathe is that the two points determine a line so unless they are grossly off it will still function.
No. 2 is the photo requested showing how a heavier unit is made by separating the two hole pieces so that they can be mounted between two thin sheets of bent metal by welding. I spent a great number of hours substitute teaching in a welding shop so had no trouble challenging better students to see if they could run the bead without blowing out the side of the lighter sheet metal strips. The advantage of this is a longer support for the runners and the ability to drop it into the vise without having to line it up. I also am not limited by the length of the original hinge.
No. 3 shows how a sheet of rubber fits into the slot sawed into the side of the wooden block. As I mentioned before I hold it into the slot with a desk stapler. I staple it in and then use a heavy duty cutter with a spacer to slice off the final size of the squeegee blade. As you can see the wood is about 1.5x4 inches which matches very well the length of the burnisher for the back and forth stroke.
No. 4 shows how the squeegee and the file are positioned at the start of a filing stroke. The file would be lifted for the backward stroke for filing but burnishing is just the back and forward motion.
There have been several mentions of polishing and burnishing. Although I call these pivot polishers I tend to emphasize to my students that the clocks that they work on by and large can be serviced by using a combination pivot file and burnisher. The rule of thumb is that if the pivot can be cut with a file, avoid polishing compounds. If the file doesn’t cut it your only option is to use abrasive materials.
Most of the work in my unit is involved in making the runners. Those eight individual ends are really time consuming. But I fail to see how a notch in the end of wood can accommodate the vast array of pivots one is faced with in giving them the care they need.

 

[bangster]

A question:

Why use a turns or pivot polisher instead of a lathe?

Just askin'...

 

[Walesey]

Easy question to answer Bangster.

Because I don't have a lazy $2000 lying around to throw at one!

(I do have scrap wood in the shed, and I can possibly afford a door hinge, if I could borrow a lathe and thread taps to make the parts that Charles describes.)

Cheers
Walesey

 

[Charles E. Davis]

Easy question to answer Bangster.

Because I don't have a lazy $2000 lying around to throw at one!

(I do have scrap wood in the shed, and I can possibly afford a door hinge, if I could borrow a lathe and thread taps to make the parts that Charles describes.)
Walsey

Actually the first ones I made were with a hand drill, hacksaw, file, jewelers saw for the runners, and any other tools could have been avoided by using JB Weld. You only need one tap to match any handy size of bolt you use for the set screws. Look at the thread shown in the second or third message of this thread and see the hinge set made by a teenager. You don't have to use wood.
Rather than have to drill all of the different sizes for the runners get a drill matching a No III KWM reamer and drill holes in the ends of the rods and sweat solder the different sizes of bushings needed in them. I was lucky to have an old brass piece of tubing that was perfect. It was scrap from something I had torn up and I have never been able to find any more of it.

 

[ddhix]

Charles,

I just wanted to tell you Thank You for the design. I originally saw it a few days ago, and decided to make one. It's a very nice design. All I really went off was the one picture I saw.

Thank you, too, for your posts here. A lot of the ideas you threw out, I had no idea. The JB Weld idea is genius; gonna do it tomorrow, saves from having to order 5/16" brass rod.

Thanks again!
Dustin

 

[lirenrui]

How do you keep it from cutting a grove into the arbor?? And how do you displace the heat form not turning the material blue. Or work hardening the material.

H/C

two ways:

1.control the rotate speed.
2.the L type support is soft steel. it does not cutting a grove into the arbor.

Actually it does not turning the material blue.

li renrui

 

[lirenrui]

Thanks for those good words from shimmystep. You ask about the other polisher that I make. I shipped the lightest unit to you for obvious reasons.
I am posting four photos and I hope I can get them in this order, If not they will be obvious when you see them.
No. 1 is the original pivot made from the three hole edge as the first prototype that I made. It has metal bushings and the box screw used to tighten the runners. (I was given a huge box of these and except for shortening them, they have worked out well.) As I mentioned in a previous message I have shifted to using JB Weld instead of the metal bushings. By line drilling the two holes I get a more consistent alignment. Of course one advantage of the dead center lathe is that the two points determine a line so unless they are grossly off it will still function.
No. 2 is the photo requested showing how a heavier unit is made by separating the two hole pieces so that they can be mounted between two thin sheets of bent metal by welding. I spent a great number of hours substitute teaching in a welding shop so had no trouble challenging better students to see if they could run the bead without blowing out the side of the lighter sheet metal strips. The advantage of this is a longer support for the runners and the ability to drop it into the vise without having to line it up. I also am not limited by the length of the original hinge.
No. 3 shows how a sheet of rubber fits into the slot sawed into the side of the wooden block. As I mentioned before I hold it into the slot with a desk stapler. I staple it in and then use a heavy duty cutter with a spacer to slice off the final size of the squeegee blade. As you can see the wood is about 1.5x4 inches which matches very well the length of the burnisher for the back and forth stroke.
No. 4 shows how the squeegee and the file are positioned at the start of a filing stroke. The file would be lifted for the backward stroke for filing but burnishing is just the back and forward motion.
There have been several mentions of polishing and burnishing. Although I call these pivot polishers I tend to emphasize to my students that the clocks that they work on by and large can be serviced by using a combination pivot file and burnisher. The rule of thumb is that if the pivot can be cut with a file, avoid polishing compounds. If the file doesn’t cut it your only option is to use abrasive materials.
Most of the work in my unit is involved in making the runners. Those eight individual ends are really time consuming. But I fail to see how a notch in the end of wood can accommodate the vast array of pivots one is faced with in giving them the care they need.

sorry, I think this method is not the best, because of the turn speed is too slow. pivot can not be polishing better.
one hand with wood to do turning, another hand with file to processing, effect is not good I think.

sorry, please forgive my reckless.

li renrui

 

[shutterbug]

sorry, I think this method is not the best, because of the turn speed is too slow. pivot can not be polishing better.
one hand with wood to do turning, another hand with file to processing, effect is not good I think.

I agree with this statement, but feel any attention to pivot condition is valuable. It will take much longer this way, but I'm sure good results can be achieved.

 

[moe1942]

Easy question to answer Bangster.

Because I don't have a lazy $2000 lying around to throw at one!

(I do have scrap wood in the shed, and I can possibly afford a door hinge, if I could borrow a lathe and thread taps to make the parts that Charles describes.)

Cheers
Walesey

Nice job...you can soup it up with a weed eater universal motor, an oring and appropriate size pulley.. Hobby shops have inexpensive pulleys.. Use a sewing machine foot control rheostat to regulate speed. It will give you the same results as a lathe. Can usually scrounge all the parts except the pulley.

 

[R&A]

two ways:

1.control the rotate speed.
2.the L type support is soft steel. it does not cutting a grove into the arbor.

Actually it does not turning the material blue.

li renrui

How low of a speed are you using. To really get a polished surface you have to go at a high rate of speed. Soft steel. What steel is that soft. Aluminum ??

H/C

 

[Charles E. Davis]

I'm not sure that speed is the only requirement for polishing. Sure it may accomplish it faster but rigidity and stability of the mounting and pressure are two very important factors. The distance, which is what speed implies is related to speed of production, not the final result.
You should see the wheel spin with the short fast reciprocating motion of a squeegee in your hand on that small arbor. We forget that the early craftsmen did amazing work without the benefit of live center lathes. A simple hinge can provide a functional substitute for the turns that they used for a great portion of their needs.
Many of us are concerned that our work be of high standard, but we are not forced by time needs to have the latest equipment.

 

[shimmystep]

I'm not sure that speed is the only requirement for polishing. Sure it may accomplish it faster but rigidity and stability of the mounting and pressure are two very important factors. The distance, which is what speed implies is related to speed of production, not the final result.
You should see the wheel spin with the short fast reciprocating motion of a squeegee in your hand on that small arbor. We forget that the early craftsmen did amazing work without the benefit of live center lathes. A simple hinge can provide a functional substitute for the turns that they used for a great portion of their needs.
Many of us are concerned that our work be of high standard, but we are not forced by time needs to have the latest equipment.

Can you quote me via a PM Charles on shipping one of your larger models? I have had some great results with the one I have, it does take a little longer to do as you say, however it also helps to avoid mis-shaping the pivot when re-facing it, just by taking ones time. Working a little and checking what you've done. I have been able to use the one I currently have with longer arbors by holding a brass staking plate in a press drill vice and using just one end of the hinge I have already. Works well but would be useful to have the larger one. Here's a pic of a pivot, from a longcase movement, I polished this weekend on your hinge, to show that one can get quite good results from this method. It required refacing initially to get rid of the deeper grooves

Taken through x15 mag loupe

 

[lirenrui]

How low of a speed are you using. To really get a polished surface you have to go at a high rate of speed. Soft steel. What steel is that soft. Aluminum ??

H/C

speed is about 1000 r/min.
the so-called "soft steel" can be bent, no hardening. not aluminum.

li renrui