CDP BACKHOE BUILD

[Taylortractornut]

My old Ford has a chain swing for a 14 foot machine its good. but it has a cylinder on each side of the boom to pull the chain around. I also use a Ditch Witch that has the single steering type cylinder and a chain on each end. It works goo has a chain adjustment about a 3/4 inch rod with fine threads on it on each end of the chain. The previous owner got shed of the attachment we used on our machine because it had too much slack and he had stretched the chain. He was diggin on a gravel slope on his summer house at the lake. He pulled the machine down the slope and it got loose and hit a bank and stretched the chain. DW wanted 350 for a new chain bearing supply sold me all the stuff to fix it for 85. I put it on the machine we used but didnt have a diggerfor it.

 

[SLOWMANDOWN]

Ok! Learnt a big lesson this week, when welding things warp and distort. The swing receiver that I welded together was done at school where I am taking a course to improve my welding skills. I omitted to bring the boom pole and bushings, and the piece was not complete before time was up, anyway it was far hot to release the clamps and transport back home. The instructor said he would finish the welding the next day and I could pick it up the day after. Unfortunately was unable to work on it over the weekend until last night. Place the piece with frame pivot, worked well but needs a ring shim of 0.0625 ( no problem). Get the boom and KABOOM!!!
The boom does not fit the swing receiver ears have warped inward by about 1/32 to 1/16 each side. Spent the morning trying to readjust so it will fit, I will only know in a couple of hours when it is cooled down and I can remove the clamps and such. I am still surprised that even with extra care and bracing the pieces still found a way to warp. (Believe me clamps and braces were well placed) This problem may seem small to some of the experienced welders and fabricators but my heart stopped yesterday when it did not fit. I will post pics soon on the progress of my build. If someone has some suggestions on how to prevent warp age while welding plates it would be highly appreciated.

 

[J_J]

Ok! Learnt a big lesson this week, when welding things warp and distort. The swing receiver that I welded together was done at school where I am taking a course to improve my welding skills. I omitted to bring the boom pole and bushings, and the piece was not complete before time was up, anyway it was far hot to release the clamps and transport back home. The instructor said he would finish the welding the next day and I could pick it up the day after. Unfortunately was unable to work on it over the weekend until last night. Place the piece with frame pivot, worked well but needs a ring shim of 0.0625 ( no problem). Get the boom and KABOOM!!!
The boom does not fit the swing receiver ears have warped inward by about 1/32 to 1/16 each side. Spent the morning trying to readjust so it will fit, I will only know in a couple of hours when it is cooled down and I can remove the clamps and such. I am still surprised that even with extra care and bracing the pieces still found a way to warp. (Believe me clamps and braces were well placed) This problem may seem small to some of the experienced welders and fabricators but my heart stopped yesterday when it did not fit. I will post pics soon on the progress of my build. If someone has some suggestions on how to prevent warp age while welding plates it would be highly appreciated.

Don't feel bad, mine did the same thing. I had to grind some off both sides to fit. I suppose a small hyd jack would spread the tangs. Another way is to cheat on the lean of the tangs. Whichever side you apply the heat, it will push away. So the trick is to weld inside first, or put a shim between the two pieces. Still another way is to put a small piece of the sane tubing that you are using for the boom, in between the tangs, plus shims if you want it loose. If you weld on the outside first, it will push to the center, If you play with heating steel enough, you can make it bend in whatever direction you want. Whichever side of a steel plate you apply heat to, the molecules will expand, and therefore bend or warp.

 

[SLOWMANDOWN]

Thanks for the support. The piece cooled down now and seems to fit with 1/64 to spare. It's not perfect but I believe it will work. Since I do not have torches at home I brought the piece to work were one of the mechanics helped me spread the plates. We first cut 3 solid bars 1 1/2 x 1 1/2 3 and 1/16 long and spread the plates with a duck billed hydraulic spreader. Placed and positioned the bars and then heated the backside of the welds, clamped and let cool. One side is slightly more warped than the other but I believe it will be OK. At least the bushing fits.

 

[David Devuono]

I know exactly what your talking about. It took me about 4 hours to assemble my backhoe last week, prying, wedging and spreading pieces to make them fit. Things certainly will be tight for a while.

 

[SLOWMANDOWN]

Hey David, I was woundering if your hydralic guy had another 6 spool hydraulic valve at the price you got yours. Thanks for your reply.

 

[dfkrug]

I am still surprised that even with extra care and bracing the pieces still found a way to warp. (Believe me clamps and braces were well placed) This problem may seem small to some of the experienced welders and fabricators but my heart stopped yesterday when it did not fit. I will post pics soon on the progress of my build. If someone has some suggestions on how to prevent warp age while welding plates it would be highly appreciated.

Heat management and the problems experienced with expanding steel is not
a small issue even for experienced welders. When 2 pieces of 1/2" plate
bend just a 1/16" or so, it is VERY hard to bend them back. I have tried
to fix heat warpage with a Porta power, 20T press, sledge hammer, etc. Not
always with success. The solution is to plan for the way the steel is going
to bend. Also massive amounts of pre-heating can pre-expand the steel
before the movement is constrained. Some or all of this pre-heating can be
done by welding the non-constraining parts first. I have learned heat
management at the "school of hard knocks". Maybe some of the pro welders
on TBN can chime in here with the methods they use.

Finally, you may notice that some factory-welded products (like backhoe
attachments) allow for extra spacing to accommodate heat distortion.
Then you may want shims to fill the gaps after welding.

 

[SLOWMANDOWN]

So dfkrug are you saying that when welding for example 2 plates which sandwich a rectangular tube which are to be welded on the inside ( only ) as the next part I will be completing ( see pic ) that it would be a good idea to pre heat the backside prior to welding. I do understand that welding for great part is heat management. I understand that when I weld the inside of the plates that they will pull in towards each other, other than supporting with braces and say alternating my welds, will preheating assist to control the warpage? If so does the pre-heat have to be red hot?

 

[dfkrug]

So dfkrug are you saying that when welding for example 2 plates which sandwich a rectangular tube which are to be welded on the inside ( only ) as the next part I will be completing ( see pic ) that it would be a good idea to pre heat the backside prior to welding. I do understand that welding for great part is heat management. I understand that when I weld the inside of the plates that they will pull in towards each other, other than supporting with braces and say alternating my welds, will preheating assist to control the warpage? If so does the pre-heat have to be red hot?

Do the inside only or the outside only to give the side plates some freedom
to expand. Preheating helps, too, and it does not have to be red hot. If
you weld the outside seam all the way (stitched), you will get considerable
heat into the plates. Clamping will be necessary as the unsecured side of
plate will try to move away from the tube. Allow for some distortion of the
side plates by leaving clearance for your cyl cross tubes.

Of more concern is your bushings. I describe how to keep them aligned in
my 4-in-1 thread. Don't tack them in until the side plates are welded. Then
weld them while the side plates are hot. Use guide pins that fit very tightly
inside the bushings. You will not be able to remove them until the steel
cools. I have not had to ream out bushings in a long time. I wish that
Mikulas at CADPlans had been more knowledgeable about heat management.

 

[J_J]

So dfkrug are you saying that when welding for example 2 plates which sandwich a rectangular tube which are to be welded on the inside ( only ) as the next part I will be completing ( see pic ) that it would be a good idea to pre heat the backside prior to welding. I do understand that welding for great part is heat management. I understand that when I weld the inside of the plates that they will pull in towards each other, other than supporting with braces and say alternating my welds, will preheating assist to control the warpage? If so does the pre-heat have to be red hot?

In the picture, if you are welding on the inside at the top of the 4 in box tubing, The side your welding on will expand and probably tilt the top of the bracket outward. You could also use a 1 in bolt to tighten the assembly down For a little more insurance, , I would put some 1/64 washers on either side of the cylinder end , before welding. If you are welding with cored wire, wrap the cylinder shaft to prevent any weld spatters. You don't need the cylinders in place if you substitute a tube for the shaft of equal dimensions. However if you want to keep the alignment, then the cyl is necessary. I tried to align some of my tabs with a square only, and I was off a little bit.

In theory, if you heat one side of say, a metal plate , it will tend to expand on that side, and if you heat the other side the same, it will try and bend back. It may also twist. So it might be possible to manipulate the metal somewhat to the desired effect. Meaning, to make it work for you.