Tapering the thickness of a Main Spring the Easy Way - Bob Roller

[Daryl]

Here is my method of tapering a mainspring lower limb and after forging
I do the same to the upper leaf. Save a lot of work.The pictures appear to show a tilted
head on the milling machine but that is NOT the case.IF the head was tilted it would let
the end mill generate a deep radius all the way across.

[bama]

Thank you Bob for sharing your knowledge. Without the sharing of knowledge we have to keep reinventing the wheel. 😁

[L. Akers]

Slick fixture!

[Bob Roller]

Slick fixture!

Thanks for the kind comments. This thing is nothing but common keystock
1/2" square and offset pins to establish a taper.The spring blank shown had
been draw filed and the picture obviously posed.The taper can be easily adjusted
by putting shims under the front pin.The thickness of the material is 1/8" 1075.
The claw or hook for the link to the tumbler is formed from the  front end of the
spring where the clamp holds very tightly.
If a milling machine is not available this type of fixture can be used for hand filing the taper.
Clamp it in the bench vise and go at it first with a coarse file and then finer cuts and finish
by draw filing and adding a few drops of threading fluid if you have some.Makes for a cleaner job.
Bob Roller

[JBJ]

Mr. Roller,
Thanks!!! Faced with the need to make a mainspring and dreading it! The holding fixture looks to be the "ticket" to making life easier. Again, thanks.
J.B.

[P.W.Berkuta]

Bob - I'd like to see the fixtures you use to form the hook and bend of the upper leaf of the spring .

[Rolf]

Thanks for the tip. I'll try it out when i start on the spring for the two Locks I am building.

Best regards
Rolf

[Bob Roller]

Bob - I'd like to see the fixtures you use to form the hook and bend of the upper leaf of the spring .

P.W. and the rest of you.My "fixture" would make a dog laugh. It is a 1/8" diameter
chainsaw file carefully ground flat on two sides and that narrowed radius forms the semi circle for the link
after notching it with a sharp three cornered file.The shape of the hook is then formed with a few file strokes.
As for bending I will see if I van get our son,Eric down here to take a picture or two of how I do that job.

Bob Roller

[Metalshaper]

Bob,

 I'm much more low tech! I use a flat plate of aluminum and crystal Shellac as my holding fixture.

I sprinkle a small pile of shellac onto the plate and warm it just enough to make it fluid. The spring stock is set in and moved around enough to get it bedded into the goo.
the heat is removed and the whole thing allowed to cool down. I clamp the plate  in the mill vise indicating the angle I need.. Then just lightly shave the stock down, so as to not overheat the part..  once done, I heat the plate to release the part and drop it into some alcohol.. after a bit the remaining shellac dissolves and the spring wipes clean..

Works for me anyways! ( and better than cyanoacrylate   )

Respect Always
Metalshaper/Jonathan

[Buffaload]

I usually do this on a shaper that way the machining marks run the length of the spring reducing stress risers.  I guess you polish all the marks out of a spring anyway so it wouldn’t matter.  I just like to use the old shaper.
Ed

[Jim Kibler]

Bob,

Thanks for sharing this.  It's nice to see your fixture.  A neat design with the pins.

All the best,
Jim

[Darrin McDonal]

I guess I am missing something here & correct me if I did.. I believe you said that you forged the spring. The taper is forged into the spring. Why have a complete set up to machine it when a couple more hammer blows does the same thing?
Darrin 

[Bob Roller]

I guess I am missing something here & correct me if I did.. I believe you said that you forged the spring. The taper is forged into the spring. Why have a complete set up to machine it when a couple more hammer blows does the same thing?
Darrin

I have never tried to forge a taper into a spring. I bend the spring and then hit
it with a hammer while red hot and forge the upper and lower limb together.
I taper the upper limb on the mill and file and polish it and then heat it up again
and open it up to wherever I want it to be in relation to the link.
I think we have two definitions of forging here.

Bob Roller

[Bob Roller]

Bob,

Thanks for sharing this.  It's nice to see your fixture.  A neat design with the pins.

All the best,
Jim

Jim,
Thanks for the note. Are you coming to Lexington in a few weeks. We hope to
but my wife has really painful back and knee problems that may prevent it for us.
How's that good looking little boy doing? Before 1979 we lived in a big old 9 room
house and my wife had a day care for infants and toddlers,usually 5 which is the
limit here without a license. The mothers really liked the care Brenda gave them
and accused me of spoiling them.  I asked them if there is any other reason to have them around

Bob Roller

[Darrin McDonal]

Ok Bob now I got it. Sorry. Yep I mistook the forged contexts.

Darrin


I guess I am missing something here & correct me if I did.. I believe you said that you forged the spring. The taper is forged into the spring. Why have a complete set up to machine it when a couple more hammer blows does the same thing?
Darrin

I have never tried to forge a taper into a spring. I bend the spring and then hit
it with a hammer while red hot and forge the upper and lower limb together.
I taper the upper limb on the mill and file and polish it and then heat it up again
and open it up to wherever I want it to be in relation to the link.
I think we have two definitions of forging here.

Bob Roller

[Jim Kibler]

Bob,

Thanks for sharing this.  It's nice to see your fixture.  A neat design with the pins.

All the best,
Jim

Jim,
Thanks for the note. Are you coming to Lexington in a few weeks. We hope to
but my wife has really painful back and knee problems that may prevent it for us.
How's that good looking little boy doing? Before 1979 we lived in a big old 9 room
house and my wife had a day care for infants and toddlers,usually 5 which is the
limit here without a license. The mothers really liked the care Brenda gave them
and accused me of spoiling them.  I asked them if there is any other reason to have them around

Bob Roller

Bob,

Thanks for the message...  Little Henry is doing great.  He's growing like crazy (15lb 10oz at two months!) and seems to be changing every day.  He's certainly a lot of work, but wonderful to be part of our lives.  It really is a great thing.  I don't think I completely understood this before having a child.

Katherine, Henry, my mother and I will be at the CLA and are looking forward to it.  Sure hope you and your wife are up for the trip.  Look forward to saying hello.

All the best,
Jim

[Bob Roller]

Ok Bob now I got it. Sorry. Yep I mistook the forged contexts.

Darrin


I guess I am missing something here & correct me if I did.. I believe you said that you forged the spring. The taper is forged into the spring. Why have a complete set up to machine it when a couple more hammer blows does the same thing?
Darrin

I have never tried to forge a taper into a spring. I bend the spring and then hit
it with a hammer while red hot and forge the upper and lower limb together.
I taper the upper limb on the mill and file and polish it and then heat it up again
and open it up to wherever I want it to be in relation to the link.
I think we have two definitions of forging here.

Bob Roller

Darrin,
As much as possible I tend to think in terms of machine tools and ways they can be adapted.
I am well aware of the CNC systems now in use and I used an old type back in 1971 in a shop
that sub contracted making parts for the mining industry.Lock making is an odd trade/skillset
today and the fact that anyone even will consider doing it is even beyond odd.I have only found
ONE machinist that wanted to do it and he did.His name is Sid Estep and he is still working but
for the railroad. He made some good locks and triggers but this was in the mid 1970's and the crappy attitude
of so many muzzle loading enthusiasts about paying for the time and skill it takes to make them made
him decide to quit and never look back. I bought his castings and spring steel and used them for quite
a while.He made the Chet Shoults Ketland and Hawken locks and triggers.I wonder how many others
have quit trying to make ANY items for the muzzle loading sports because of this? I  was fortunate
and made connection to Germany's Black Powder shooters thru Guenter Stifter and Helmut Mohr.
I sent a few lock samples to them and that opened another market for me and I was glad to have it.
THIS forum has been beneficial and a local police officer took me to the CLA Lexington Show for the
first time in 2008. It was a real pleasure to see such a fine show in a very pleasant environment and
the absence of ammo-camo-AK"s,AR's and relics of defunct,criminal political systems was indeed a
pleasurable experience.I hope we can come to the next one but we're not sure at this time.

Bob Roller

[Bob Roller]

Bob,

Thanks for sharing this.  It's nice to see your fixture.  A neat design with the pins.

All the best,
Jim

Jim,
Thanks for the note. Are you coming to Lexington in a few weeks. We hope to
but my wife has really painful back and knee problems that may prevent it for us.
How's that good looking little boy doing? Before 1979 we lived in a big old 9 room
house and my wife had a day care for infants and toddlers,usually 5 which is the
limit here without a license. The mothers really liked the care Brenda gave them
and accused me of spoiling them.  I asked them if there is any other reason to have them around

Bob Roller

Bob,

Thanks for the message...  Little Henry is doing great.  He's growing like crazy (15lb 10oz at two months!) and seems to be changing every day.  He's certainly a lot of work, but wonderful to be part of our lives.  It really is a great thing.  I don't think I completely understood this before having a child.

Katherine, Henry, my mother and I will be at the CLA and are looking forward to it.  Sure hope you and your wife are up for the trip.  Look forward to saying hello.

All the best,
Jim

Jim&Katherine,
 Certainly no failure to thrive with baby Henry. It's easy to see in infants
if they have a fine home environment. I came across an 11 month old boy recently
in an Aldi's grocery store and he was obviously happy and well cared for.
He reached for me and I "shook hands"with him.His mother was a bit surprised
but I told her a happy baby frequently can tell if a stranger really likes him or her.
They are a lot of work but SO worth it and we enjoyed every minute of it.
Our youngest son will be 46 on 29July and his daughter and husband have made
us great grand parents twice with now 3 year old Lilly and Lucy who is today 1 year
old.

Bob Roller

[Daryl]

Heart-warming experiences - thanks Bob.

[Bob Roller]

Heart-warming experiences - thanks Bob.

Daryl ,
Thank YOU for posting that picture and I hope it will help someone
by showing that tools don't always have to be costly. I think the
monetary value of that little bar is less than $1.00 including the screws

Bob

[rich pierce]

An expert machinist with a complete shop will find one way easy and an expert blacksmith will find another way easy. The builders without daily access to either a machine shop or a forge find some tasks hard or just laborious. A mainspring is just about at the limit of what I can forge using fire brick enclosures and propane torches. Since I only have to make one every couple years, that’s ok. 

[JCKelly]

You all are professionals

As a pretty rank amateur my own milling machine came from Nicholson

[Bob Roller]

You all are professionals

As a pretty rank amateur my own milling machine came from Nicholson

I believe that is called an Armstrong milling machine

Bob Roller

[David R. Pennington]

Rough forged frizzen spring blank for a big lock I am working on. Lots of ’armstrong’ milling to do yet. I’ll file to thickness, then file the pin and locate and drill screw hole. Then I bend and fit it before heat treating.




al2br6

[Bob Roller]

I wouldn't even try to do that job in that manner.I get tired just thinking
about it.One thing is,I have no good way to do it and have no forge as such
but have adapted other methods that will do the job faster and easier.
MAYBE,60 years ago I might have tried these very old methods but now
there is no way I'd even start it.
Please continue this and I would like to see it when it's done and the time
it took to do it.

Bob Roller