bandsaw blade welder (old one)

[2M MACHINING]

Can anyone steer me in the right direction to a schematic for a bandsaw blade welder.I have an old one im trying to get working but it is missing something to limit the current at the weld point.
?.

[Chris Smith]

What sort of welder is it? <p>Spot welder, Tig, Mig, contact, brand, model?<p>Age,country of origin? ETC.

[josmith]

A common way to limit welding current is to run a dc current in a seperate winding in the transformer. Sometimes that circuit goes bad.
On a blade welder you have to develope skill to do it right, you can have problems even it it's working ok.

[2M MACHINING]

Chris, The type of welding this machine does is to join two ends of bandsaw blade material togather.Either to repair a broken blade or to make a new blade from roll of blade material. The mechanics of the machine are such. One end of the blad is held in a stationary clamped position this clamp is connected to some type of current source (this is the part that is missing). The other end of the blade is set into another clamp that has a spring loaded slide and allows the two ends of blade to butt up against each other,this clamp is connected to ground. What should take place when the weld button is pressed is,current runs through the blade and at the butt joint the metal should liquify allowing the spring loaded clamped blade to slide toward the stationary blade joining the two ends,at the same time the clamp that slides breaks a switch to stop current and the weld cools.<p>Need to go back and search make,model,year,dont have that info with me now.<p>Thank you

[Chris Smith]

I am familiar with welders, I just need to know what type you actually have.

Blade welders come in all sorts and types. <p>Spot welders, induction welders, fusion welders etc, even tig welders do that job.<p>Your sounds like a induction type welder?<p>They charge up a given amount of joules/watts/amps/volts into a cap and coil, and then dump the load all at once to make a “spot” weld out of the existing material ends where they meet.<p>They also use resistance welding and pump in a current to the tips, which heat slowly and fuses together the joint. <p>This relies on the fact that electricity travels the shortest path, and doesn’t heat the rest of the long blade on its shorter journey between tip clamps. <p>Tig welders are the most successful types of joint welders.<p>[ May 07, 2005: Message edited by: Chris Smith ]</p>

[2M MACHINING]

Chris,sorry im the one unfamiliar with welders thus the long explation of function.<p>I think there are a couple of transformers in the base of the saw . no clue of what they connect to.<p>would this lean toward induction welder type?<p>I think the make is powermatic.<p>thanks

[Chris Smith]

What does the clamps do besides align the blade? <p>Is there any cable connections to these clamps, is there a "stick feeder" near this area, are there large cables in the system and area? <p> Large caps or coils [½ inch bar stock wrapped around a air core] <p>Any diode banks?<p>A NAME plate and model? <p>There are soo many different types of welders, and methods of welding. <p>The common types of old was the induction type like a spot welder. But others had clamping or heating plates that swung into action on both sides of the blade, one positive the other negative.<p> And then the fusion type used the blade as the electrode. <p>And the tig types had a movable “stick” where an arc carried the current and it was on a rail for guidance across the blade.

[2M MACHINING]

I take that back, I think we can eliminate induction welder. It seems to me the function is more like spot welding.

[Chris Smith]

Ill try to describe just some of the welders, and what they might look like?<p> [in some similar way but not exclusive?]<p>A induction type of welder has large caps and coils inside [the power supply] to”shunt” a stored amount of energy into a quick weld. <p>A spot welder does this by pinching two “pinch clamps” made of a material that is not “Steel or iron” at a focus point, and the clamping action with the quick jolt of current make a path between two piece of metal [sandwiched], and its almost in absences of oxygen so it doesn’t need a flux, and its so hot and so fast,... plus the clamping,.... that it melts together and cools just as quick.<p> These types [of blade welders] may have flat plate at the bottom, and a narrow V like clamp at the top [wider than the weld area by two or three,... 1/8 inch or so? ] and it goes across the blade where they meet to make contact with the bottom plate, the top plate defines the heated area, and the two ends of the blade are brought together, then pinched with the plates, and zapped. This forms a heat spot, about 1/8 inch wide to form the weld made out of the original blade material. <p>Spot welders have a tiny spot like a pencil, and do the same thing, only smaller. And they stack [sandwich] the metal and weld it, where the blade welder is side by side weld. <p> These types will have large coils that look like ½ inch bar stock, and the welders are generally heavy, and heavy duty looking in all aspects. They have a “pinch” device like a pair of welding Vice grips, and the ends are all blackened over the ages and have power cables leading to them. <p>The Tig welder will clamp the blades, and have a mechanism that feeds in a stick [tungsten] and it strikes an arc and has a gas feed to keep the weld clean and free from oxygen as you drag it across. It fuses the two ends together under a arc and shield of gas to keep contaminated metals out that would fatigue or weaken the joint, if added. <p>The fusion type welder will have clamp plates at the blade ends, and swing in towards each other. They will have leads on each clamp and may or may not be induction type of transformer. Some require a fluxing before the weld is applied. As they come together they are arced, or pulsed, and the two ends melt under a slight pressure and heat to “fuse” togther. Then the joint is ground down after it cools because a “bump” of large material is formed in this process. <p>And then others are just clamps that align a blade, while a welder comes along and manually welds the thing by any means including bronze nickel joints with a oxy torch. <p>This should lead you to what yours type might be? What is the action look like where the blade is clamped. What moving parts are here, cables, etc.

[2M MACHINING]

Chris, by your discriptions the fusion type is very close, By futher inspection of unit i belive the power supply is missing.<p>info plate: Powermatic,blade welder
model:600,60hz,15Amps,220V.<p>thanks

[Chris Smith]

Do you have clamping jaws, or swing in type of jaws?

[2M MACHINING]

Chris, One clamp has two sets of brass pads about 2" apart that pinch the blade between them for continuity and alignment.The clamp is actuated by a cam type swing lever, this clamp is isolated from the rest of the frame,there is a terminal attached to the back of this clamp for a lead.<p>The other clamp has same design of brass pads.with swing cam lever for pinch an alignment and continuity to the frame,this clamp is attached to another lever which has several setting positions,first position reads clamp(i assume this is where the two ends of blade are pinch,aligned,and butted togather). then a series of holes for the lever to lock into,which puts spring pressure at the butted blades.

[Chris Smith]

Sounds like a fusion welder.

The power supply can be either surge type [pulse], or constant current type.

[lkraemer]

2M MACHINING,
I was wondering if you have ever used a Blade Welder of this type in the past? What makes you think that isn't working properly. They are pretty simple and I have yet to see one that is
defective. I have made a lot of welds on the
units where I used to work.<p>If you wish I can tell you how I have used these in the past to make perfect welded blades.<p>I had a manual with schematic until I retired and I tossed it in the trash. I had it stored for 28 years.<p>
LK

[lkraemer]

2M MACHINING,
Steps for perfect welds (if I can remember correctly)
Get some scrap blade material and practice making a few before using good blade stock.
Use Standard Blade stock, not BI-Metal type.<p>1. Cut Both Ends SQUARE with the cutter on the
Welder.
2. The left clamp is fixed. So clamp the Left portion of the Blade. If I remember correctly the teeth are supposed to point towards your body.
3. Move the Right movable clamp to the (LEFT)straight down PIN position, then clamp the Right portion of the blade. The ends of the blade now should have a very small gap between them and be aligned perfect. Move the Right movable clamp to the center PIN (in its range) and stop there.
You have now applied pressure to force the welding process to mate the two ends. Adjust
as necessary to get a good weld.
4. Depress the WELD button and hold. Sparks will fly and the weld will terminate.
5. Unclamp the weld when it is cool.
6. Turn the blade around so the teeth are pointed towards the welder.
7. Move the Right movable jaw to the MAX right
position.
8. Clamp the blade in the center of both jaws.
9. Depress the Anneal button until the blade is BRIGHT CHERRY RED and then let it cool some.
As it cools keep cycling the Anneal button to make the blade cool in slow steps. This will take about 6 to 7 cycles to get it to where the blade is just slight red at the weld point. One or two more quick depresses will help anneal.
10. Let blade cool and remove.
11. Grind the weld flat with the small grinder on the welder.
12. Wiggle the blade easily and see if the weld holds.
13. You should be able to twist a 65 1/2" blade into three loops and not have it break the weld.<p>Zit Zot it is done.<p>LK