How to Bend Mild Steel?

[RVJimD]

morning all,

I am going to build a valve spring compressor tool for a parallel valve Lycoming engine and the first step I want to try is making the "V" shaped fork that will rest on the spring and it gets compressed using a simple machine screw. So, how would you bend this? My first attempt was simply put it in the vise and apply force. Well, needless to say, it doesn't come out square and is difficult to control where the bends and flats end up.



It is cheap mild steel from the local farm store, 1/2 X 1/8" bar. Should be more than adequate for the task if I can get it bent.

My next thought is to mill a simple forming block pair and try putting it in the press. But before I start that I thought I would see what sort of tips I get from the group here.

Thanks,

Jim

 

[RandyM]

morning all,

I am going to build a valve spring compressor tool for a parallel valve Lycoming engine and the first step I want to try is making the "V" shaped fork that will rest on the spring and it gets compressed using a simple machine screw. So, how would you bend this? My first attempt was simply put it in the vise and apply force. Well, needless to say, it doesn't come out square and is difficult to control where the bends and flats end up.



It is cheap mild steel from the local farm store, 1/2 X 1/8" bar. Should be more than adequate for the task if I can get it bent.

My next thought is to mill a simple forming block pair and try putting it in the press. But before I start that I thought I would see what sort of tips I get from the group here.

Thanks,

Jim

Jim, for the best results, you are on the right track using the press and some custom tooling.

 

[Ulma Doctor]

if you have access to a rosebud torch and an oxy/acetylene rig, you can heat it up to a dull red and bend at will
mapp gas or propane could be substituted too, but may take longer to heat up the metal. mapp is hotter than propane and will impart heat faster

 

[David S]

Jim depending on the size of your vise you could try something like this.

http://www.leevalley.com/en/wood/page.aspx?p=32011&cat=1,43456,43407

I have bent a number of things successfully with it.

David

 

[Tony Wells]

Well, unless you are set on that exact contour, you might be able to find a piece of rectangular tubing and cut to length and tack a nut in place inside it. Otherwise it's a little difficult to get a symmetrical part like that by hand bending. Press accessories are your next best bet. I made a spring compressor that was adjustable, a little larger than one for valve springs. When I get out to the shop I'll take a picture of it. It was for some automatic transmission clutch packs back when I was rebuilding transmissions. The general idea would work in many ways for spring compressors.

 

[BGHansen]

I've bent a lot of 7/8" wide x 1/8" thick HRS stock in my DiAcro 24" brake. It'll do 135 deg. bends without working up a sweat.

Before I had the brake I did some bends like you have using two bench vises and heavy steel bar stock. Did the end bends (like your ~15 deg. bends on the legs) first in a single vise. Just clamped down on it and tapped it over with a hammer. For the center bends (~ 75 deg. bends like you have), I set two bench vises next to each other and clamped a couple of pieces of 1" x 1" bar stock together with the 1/8" x 7/8" stock sandwiched in between the two bars (looked like a cross; 1" bar stock set horizontal, stock to be bent set vertical). Then tapped on the stock above and below the 1" bar stock to make the bends. Worked pretty well though the DiAcro is the way to go.

Bruce

 

[RVJimD]

Lot of good ideas, I knew you guys would have some, didn't expect any this quick! Thanks!

I wondered about heating it up. Dull red and let it cool slow, or do I need to work it while it is hot? I don't have a good understanding of metal properties. Slow cool is tempered and makes it workable? Quick quench in non flammable oil is hardening? (We don't have to go into all that, probably beyond the requirements for the project).

Thanks again guys, I'm sure there is more to come.

I think I going to try cutting the male form from hard word and see where that gets me.

Jim

 

[mzayd3]

If you are hearing it up, work it hot. I usually heat to a bright orange and bend. You'll be surprised how easy it is to move it.


Sent from my iPhone using Tapatalk

 

[Firestopper]

How many do you need? If your doing only one, then lay out the shape on your welding table and tack the piece, heat, bend, tack, heat bend until you have your piece. Start with a slightly longer piece and trim to fit. For heating a small cutting torch tip (#2 or 3) will focus heat where you need it. The flat strap your using won't require big heat.
If you need multiple pieces, the I would invest the time in building dies, wood would probably work for thin flat strap on your press. I have used this method for much thicker flat bar when only one piece is needed.
Tip, use the outside of the layout line for this method. work it while hot (medium cherry red).

 

[chips&more]

Layout the valve spring compressor tool onto a piece of cardboard in actual size. Get a piece of material extra long. Do not cut it to length at this time. Leave it long. And no hole in it yet. Start your bending at the section where the hole will be. If you have a vise, that should work just fine for bending. While in the vise, bend it over a piece of metal that’s flat and the correct width if you need to get that flat area correct. Check/compare your progress to the full scale drawing that you made on the cardboard. I don’t see the need for any heat. A lead hammer or dead blow hammer would be good. Maybe a chunk of hard wood at the bend to focus the energy when hitting the bend with the said hammer. When all your bends are done. Cut the ends to proper length and put that hole in it…bada bing bada boom!