VV2-55 Spring Question

[JerryVan]

Don't get hung up on NC or NF. A 4-40 is a 4-40, is a 4-40... In fact, all 4-40 threads should be classified as NC. The standard fine pitch variety would be 4-48, and would be marked NF. I would really hesitate to purchase taps or screws from a source that advertises 4-40NF threads.

As to seeing some screws identified only by "#8 x 1.5", that would be the proper nomenclature for a wood screw, or a very poorly described machine screw. Actually, that kind of machine screw decription from Amazon, or a Chinese seller, would not surprise me in the least.

Do you have hobby shops near you? I have sometimes found small taps & screws at a good hobby shop.

[Lah Ca]

Don't get hung up on NC or NF. A 4-40 is a 4-40, is a 4-40... In fact, all 4-40 threads should be classified as NC. The standard fine pitch variety would be 4-48, and would be marked NF. I would really hesitate to purchase taps or screws from a source that advertises 4-40NF threads.

Thank you. Most helpful, as always.

As to seeing some screws identified only by "#8 x 1.5", that would be the proper nomenclature for a wood screw, or a very poorly described machine screw. Actually, that kind of machine screw decription from Amazon, or a Chinese seller, would not surprise me in the least.

Yes. Poorly described. Offshore made. I am very familiar with wood screws, much more so than with machine screws.

Do you have hobby shops near you? I have sometimes found small taps & screws at a good hobby shop.

Near is a relative term. There are hobby shops, lots of them, in the greater regional area, yes, but none in my small suburban municipality.

However, there are big box stores, Canadian Tire, for one which do have tap sets and individual taps and a (very spotty) selection of machine screws, some of which are actually properly labelled.

The problem in the big box stores, especially Canadian Tire, is that while the staff often do know where things are in the store, they often do not have much depth of knowledge about what these things are. Home Depot is better in some departments as they do try to hire retired tradesmen, at least here. This is good for plumbing and heating and electrical work. It does not extend as reliably into machining or even woodwork, however.

I will be OK now (thank you again), I think, as least as far as the project at hand is concerned.

The only places, I suspect, where one might be able to obtain smaller tap and die sets will be very large machinist supply companies, hobby stores, large electronics stores, and suppliers for jewlers and horologists.

[MarkELynch]

Lah,

You are getting lots of patient advice from everyone but I am surprised by the number of postings for a fairly straightforward job. Are you equipped with the tools and mechanical technique to carry this out? By the time you gather the necessary tools and materials it might exceed the cost of having someone else do the work for you. Have you considered this option?

If you want to proceed you can purchase the necessary tap, drills and fasteners from this source, Everything will be mailed to your door.

https://www.mcmaster.com

Mark

[Lah Ca]

You are getting lots of patient advice from everyone...

Yes. And I am most greatful. Thank you.

...I am surprised by the number of postings for a fairly straightforward job.

What is straightforward is relative to one's background and experience. I have no background in mechanics whatsoever. Most of my valuable highschool shop classes were woodwork and electrics, although I did take one junior highschool metal work class. I am eventually capable of figuring out and repairing most things (and safely, too) if I have a mind to, but I am cautious in unknown territory. The problem here is entirely my lack of experience and the resultant uncertainty.

Are you equipped with the tools and mechanical technique to carry this out?

Partially. And I will be better equipped by this afternoon. I have an OK drill press. I have a wide variety of drill bits. I have cabinets of various and sundry useful tools, both power and hand.

But I do not have any taps or dies, yet.

I have absolutely no experience with servicing/repairing a spring. But how does one learn if not by doing?

And this all is merely a practice run on a bagged motor in preparation for doing the same job on a motor in excellent condition (apart from a broken or detached spring).

By the time you gather the necessary tools and materials it might exceed the cost of having someone else do the work for you. Have you considered this option?

It is my general experience that the careful and selective purchase of tools is an expense that is quickly recouped.

No I have not considered this option. There is one person I know of within a 500 mile radius of me who does service work on talking machines. I also live a few blocks away from a legendary Victor motor guru, but he is very elderly, and his machine shop seems largely disused. And there are horologists who would be capable of the work. But .... how would I learn?

If you want to proceed you can purchase the necessary tap, drills and fasteners from this source, Everything will be mailed to your door.

The world has become very complicated. This is not realy a feasible option now.

[Hoodoo]

I see that Canadian Tire offers several tap and die sets, one, an 86 piece set, looks like it might have what you need, or taps down to quite a small size anyway. I still use the smaller set I bought from them decades ago and it has been fine. I have purchased some “special” taps and dies when I needed them: mostly the tiny ones like 48 or 72 or 80 tpi, plus some left hand thread ones for crank handles or bicycle (left) pedals.
Go gently with the small taps, advance just 15 or 20 degrees, then reverse a bit to clear/break the chips.
There are probably good YouTube videos about cutting threads.
Cheers,
Tom.

[Lah Ca]

I see that Canadian Tire offers several tap and die sets, one, an 86 piece set, looks like it might have what you need, or taps down to quite a small size anyway. I still use the smaller set I bought from them decades ago and it has been fine. I have purchased some “special” taps and dies when I needed them: mostly the tiny ones like 48 or 72 or 80 tpi, plus some left hand thread ones for crank handles or bicycle (left) pedals.
Go gently with the small taps, advance just 15 or 20 degrees, then reverse a bit to clear/break the chips.
There are probably good YouTube videos about cutting threads.
Cheers,
Tom.

Thanks. I now have a tap set, much smaller than the 86 piece set. It contains the tap size I need.

[Jim_Cannon]

Go gently with the small taps, advance just 15 or 20 degrees, then reverse a bit to clear/break the chips.
There are probably good YouTube videos about cutting threads.
Cheers,
Tom.

I use Cutting Fluid when I cut threads. Helps make smooth threads.

[Lah Ca]

There are probably good YouTube videos about cutting threads.
Cheers,
Tom.

Thanks.

viewtopic.php?t=62303

[Lah Ca]

Well .... I have inched another short distance forward with this project. Thank you everyone!

I drilled out the rivets in opposing pairs from the drum side of the unit. The rivets did not go entirely through the metal of the drum, and there was a center-punched-like dimple in the bottom of the rivets which helped with centering the drill bit. Mostly very little of the rivets was drilled out before they spun and were pushed part way out.

Once a pair was drilled out, I tapped the pair of holes from the gear side of the side of the unit. I then put 4-40 slot head brass screws into the tapped holes from the gear side--this will be reversed later as the metal of the drum is very much thinner and softer than that of the gear plate. I then moved on to the next opposing pair.

I did not need cutting fluid or oil for tapping. There was enough residual grease left in the holes after the rivets were out.

I choose brass screws 1) because that was what was readily available in a round or pan slot head configuration and 2) because if anything is going to strip or become damaged by cross threading, it will be the brass before the steel, and brass is easily drilled out.

"Casualties?" you might well ask. Well, I did snap a 3/32" drill bit in the drill press. This was very surprising because it was in a drill press, the drill press was turning very slowly, and very little pressure was being applied. However, the bit was from what is probably my oldest index, and it has been used extensively with more wobbly handheld electric drills which tend to fatigue smaller bits. Luckily I have more bits.

Patterns of wear in the VV2-55 motor are interesting. The gears all look to be in very good condition. Where there is visible damage is on shafts, sleeves, and bearings. Everything seems quite sloppy and there is a lot of scoring despite there being a lot of dirty waxy grease. Some bearings look quite out of round. It must have something to do with torque on the bearings and shafts.