Setting up Shop Questions - from an NZ learner

[bazmak]

2 or 2.5mm rods are correct for 3mm wall tube.After practice you should not be burning thru 3mm thick unless your amps are too high.Recommended settings mean nothing,reduce your amps until its obviose they are too low with lots of sticking,then increase gradually until it feels right.Take note of setting per rod size.This can then vary slightly with a no of different factors,but its too early for you to worry about that yet.You would normally run the weld straight down the middle (WHEN THE METALS ARE OF = THICKNESS ) IN this case run the weld over to the side of the rad and thick wall letting the pool overlap to the thin edge,you will soon be able to weave side to side slightly,as in this scenario the rad of the tube forms a natural weld prep and needs more metal puddle to fill,this means slower feed ,more heat hence blow holes
Try tacking with alternate short stitchs then run a final weld over the lot.Its trial and error
and practice .I spent 2 weeks welding bits of scrap of all thicknesses in all positions in a huge sculpture.You soon learn.TRY INCLINING THE JOB AT @20o
towards you for the final weld,this reduces the heat and means you have to increase the feed slightly.For thin matls say 1 to 1.5mm thk I increase the incline to almost 45o. Regards barry

 

[XD351]

The main issue is that the tube has a radius on the corners which is the same as a bevel on one piece .
You don't want this as a bevel is what you want when you need more penetration .
You can as mentioned use a nail as filler or knock the flux off a rod with a hammer and use that or try starting your weld in the middle and run to one edge , do a couple of the other joints then come back and weld from the other edge to the middle where you started the first weld .
It's sort of like a skip weld sequence and i usually bias the arc a little toward the radius on the tube - not much say 5 - 10 deg just to stop burning the end of the tube away also i tend to stand the rod up more to 90 deg so less lead angle .
The other option is to set the tube up and contour the ends so they follow around the radius , real PIA to do as you have to allow for it when cutting the tube etc .
If you have a mig use it for this sort of stuff , life is too short to spend your time pulling hair out !

 

[joco-nz]

TRY INCLINING THE JOB AT @20o
towards you for the final weld,this reduces the heat and means you have to increase the feed slightly.For thin matls say 1 to 1.5mm thk I increase the incline to almost 45o. Regards barry

Sorry Barry I'm going to be thick. When you say inclined "towards you" is it (where 'P' == person and '/' or '\' == direction of incline):

P /

or

P \

Then depending on which is the correct one where would I be approaching the work with the electrode? If '->' is the direction of approach would it be ...

P \ <-

or

P ->\

or something else. Yeah, its been a long day at the office and I'm proper brain fried. Need beer.

 

[joco-nz]

2 or 2.5mm rods are correct for 3mm wall tube.After practice you should not be burning thru 3mm thick unless your amps are too high.Recommended settings mean nothing,reduce your amps until its obviose they are too low with lots of sticking,then increase gradually until it feels right.slower feed ,more heat hence blow holes

Barry - THANKYOU. Virtual beer to that man.

Looked up mild steel, 2.4mm 6013 rod on the Miller.com calculators. 40-90amp was there recomendation. Ok, lets start at 40amps. Only 30amps less than BOC's recommednation. Can strike an arc, keep it going and run a bead. A little challenging to keep things going but, managed it. Upped to 45amps. Easy to start and keep going. On the 30x3mm SHS the bead looked a little cold. Went to 50amps, bead seems to look good. PROGRESS! :thumbup:

Also tried putting a small tack where the end of the bead would end, right on the edge of the tube. The spot I would often blow through. Then run a bead to it. BINGO, clean finish to the bead, easy to spot where to stop and no overheat/blow through. WIN.

AND I have beer.

 

[bazmak]

Thats great,this is called the learning process.Incline is down towards you
Also after tacking at the start point strike the arc over the edge so the initial blast is away from the job then start the weld and hesitate a second to build up a bead
.At the finish go to the end and then reverse back a couple of mms.This increases the weld profile at beginning and end
When welding thinner steel and the work is inclined sloping down towards you
the flux pool tries to catch up with your weld.DONT LET IT.the flux should always be trying which helps subdue the arc

 

[joco-nz]

Been looking at the bandsaw again tonight and noticed that on the bottom wheel, that is driven my the motor, there is a ~2mm gap between the "shoulder" on the wheel and the back of the blade. When looking at the idler wheel the back of the blade is flush with this shoulder. Should I be looking to adjust things so the bottom wheel has the blade running flush with the shoulder? If I should adjust is the method to adjust the "angle" of the idler wheel?
Never having had a bandsaw of any form I'm flying a bit blind. I also did a search on youtube but haven't found conclusive footage on what to do.

Actually, this might be the answer.


Cheers,
James.

 

[rodw]

Been looking at the bandsaw again tonight and noticed that on the bottom wheel, that is driven my the motor, there is a ~2mm gap between the "shoulder" on the wheel and the back of the blade. When looking at the idler wheel the back of the blade is flush with this shoulder. Should I be looking to adjust things so the bottom wheel has the blade running flush with the shoulder? If I should adjust is the method to adjust the "angle" of the idler wheel?
Never having had a bandsaw of any form I'm flying a bit blind. I also did a search on youtube but haven't found conclusive footage on what to do.

Cheers,
James.

This is probably highlighting the issue that I covered in point 1 on the previous page. Sorry I missed your question about it. Sounds like the top pulley needs to be moved out to align the pulleys with the straight edge. I used a scrap of aluminium angle iron that I cut so it would fit inside the saw and long enough to reach both sides of each pulley. The top pulley needs to be aligned with the bottom. You may be able undo the securing bolt and used a gear puller to pull the top pulley out. I think I managed to use a few washers to space the bearing forward of the adjustment slides. The top pulley also has some alignment adjustment on the non cutting side. Hope that makes sense.

 

[goldstar31]

I suspect that I am repeating myself- and as this a 'freebie', feel a little annoyed.
I have said that you have a 6 x4 metal cutting bandsaw and regardless what your supplier or country is calling it, it is a 6 x4 bandsaw and has been that for decades. I'm on my second one. get that!

As such the information is probably excessive! Arguably, the article by John Pitkin -which runs to 9 pages should be followed.
Pitkin writes clearly and succinctly and fills in the missing gaps which the other contributors have omitted.

For my offering, I have added that as the blade needs to be twisted- Heaven knows why- I have recommended that final alignment of the blade is done by using two simple clamps which should be parallel to each other and vertical which means at right angles to the body of the machine.

It's cheap, it's crude, it's simple and once done, it is like riding a bike.

 

[joco-nz]

Read through the Pitkin missive and began looking at the saw with that procedure in mind and decided that starting on that path was a bit much for last night. So ... we made sparks instead.

First frame for desk. Still not fully welded as I ran out of time. BUT to my surprise and delight when I put a level across the top corner to corner and across the centres of the sides its FLAT on the floor. :thumbup:

 

[goldstar31]

Read through the Pitkin missive and began looking at the saw with that procedure in mind and decided that starting on that path was a bit much for last night.

A massive missive:hDe:

 

[joco-nz]

Okay started the process to tune up the bandsaw. Didn't get much time this weekend due to family demands but I managed to get some basics done.

Removed the blade and the guides from the saw to allow for assessing how co-planer the two pulleys are. Also to dial in the correct tracking a little later.

Checked that the lower wheel had no play in it - all seems solid.

Checked that the upper wheel has no play on the shaft. By this I mean the fit is nice and close but still allows free turning. However there is a little bit of play "in and out". The pulley does not have enough packing behind or in front of it.

Found some SHS aluminium that I had about to act as a straight edge and cut it to a length the would fit within the saw frame and clamped it to the bottom pulley using some spring clamps.


Then used the straight edge as a reference to ensure the top pulley was parallel to the lower one then checked measurement top and bottom of the pulley to [a] see that is parallel and to straight edge and to see what the offset is.
Looks to be 2mm.


Started to dismantle pulley and looks to be pretty simple. No snap retaining rings or anything, just the screw/washer combo.


There is a spacer behind the pulley that holds it out. So when I get my lathe I could turn something new that was the exact correct width to space the pulley. In the mean time I need to get 2mm worth of packing. That should bring things to zero offset per the Pitkin checklist.

 

[DJP]

I know that my saw has lots of play in the idler/tensioner pulley but when tightened against the blade is tracks OK. I have a feeling that the more critical tuning happens at the blade holders with guide bearings. I used to adjust the holders up tight to the work piece being cut to minimize blade twist and better vertical cuts. It didn't help so not I just leave everything set to max and renew the blade when it gets worn and starts to wander.

I don't consider this saw to be a precision machine tool and for my use to cut small pieces off longer stock it does the job.

However, I am curious to see if you can measure improvement from this tuning so keep going.

 

[joco-nz]

Did the alignment tonight, got the wheels parallel and zero improvement on tracking. In fact if anything the tracking on the lower wheel got worse. So I when back to the status quo and with the top pulley tracking perfectly ie the blade is barely touching the pulley shoulder and this is what the lower pulley looks like. A ~4mm gap to the shoulder. However it does not get any worse or better. It just sits there in this position as the saw runs.


From searching the Yahoo group I have seen mention of adjusting the lower pulley out by at least the amount of the gap. However if I do that I will have to remove the clip ring. Not to keen on that. So the converse would be to adjust the upper pulley inward. This from the Pitkin guide:

When the upper wheel tilt is correct, check the blade position on the LOWER wheel. The blade should just touch the lower wheel flange. If the blade is too far away from the LOWER flange or hard against the LOWER flange, repeat the offset adjustment by moving the upper wheel in or out on the shaft to correct the blade position, and start over.

So, looks like I need to get a couple of big washers. Found some 5/8" ones at Bunnings that are 3mm thick. The current spacer is 9mm , so a couple of these will allow me to try settings at 3 and 6mm before resorting to some card or plastic shims.

I also noticed that the wheels do not look to be the most round looking castings under the sun. It looks like the centre hole is ok, just that the rim could do with a skim. Something to look at again when I get the lathe.

Edit: Had a snoop about the garage and found two of said washers and tried them. BINGO - we have a winner. Lower pulley now tracking dang near perfect from what I can tell. Will take that win and call it a night. woohoo1

 

[rodw]

Edit: Had a snoop about the garage and found two of said washers and tried them. BINGO - we have a winner. Lower pulley now tracking dang near perfect from what I can tell. Will take that win and call it a night. woohoo1

Great work. I have worked through the Pitkin missive myself. I do have an extension to his method. The idea I suggested getting it aligned from where you are now with a steel ruler between the guide rollers and a Set square will get you closer a lot quicker than any other method.

I'm afraid my 6 x 4 is quite a dim memory now as my current bandsaw (linked to in this thread) was perfectly aligned from the get go. I recently consigned my old 6 x 4 carcass to the dump after it rusted for a few years while I worked out what to do with it..

 

[goldstar31]

I set the clearance between the rollers- as per the book. Again, I set the blade to run vertically, in and out of the cutting area with properly aligned clamps to each other. Merely a corollary to the Six Proposition of Euclid- rather than the Gospel according to someone in rightful obscurity called A.N.Other.

 

[joco-nz]

Great work. I have worked through the Pitkin missive myself. I do have an extension to his method. The idea I suggested getting it aligned from where you are now with a steel ruler between the guide rollers and a Set square will get you closer a lot quicker than any other method.

Having played with the alignment bearings originally I realise how fiddly it is i.e. As soon as you listen the bolt it's very easy to lose your setting.

So, with the ruler method, with no blade installed, I presume you are not setting the distance for the bearing that rides just over the top of the blade. On that basis how do you keep your angle adjustment when setting that height with the blade installed. I had a real fight with that part.

 

[rodw]

Having played with the alignment bearings originally I realise how fiddly it is i.e. As soon as you listen the bolt it's very easy to lose your setting.

So, with the ruler method, with no blade installed, I presume you are not setting the distance for the bearing that rides just over the top of the blade. On that basis how do you keep your angle adjustment when setting that height with the blade installed. I had a real fight with that part.

The ruler just gives you a larger alignment surface to place against the set square for both the backguage and up and down. It makes it much easier to see whats going on without fighting the spring in the tensioned blade. I also found the teeth of the blade do not let you get the square up against the blade anyway. You still need to fine tune with the blade installed to get straight cuts.

 

[joco-nz]

The ruler just gives you a larger alignment surface to place against the set square for both the backguage and up and down. It makes it much easier to see whats going on without fighting the spring in the tensioned blade. I also found the teeth of the blade do not let you get the square up against the blade anyway. You still need to fine tune with the blade installed to get straight cuts.

Cheers Rob. Will give it a whirl and see how we go.

 

[goldstar31]

Being a simple soul, Children's plastic squares are as cheap as chips and after all, cutting a notch to avoid the saw kerf set is - or should be, obvious.

When you come to having a mill, you will find that setting a vertical with a 'proper' steel square will be difficult unless you carve a chunk out for your particular vice/vise. Remember wet behind the ears apprentices 'made' their squares. I was never an apprentice- but made one.

Writing about 'childrens' drawing instruments, I once squared a Myford lathe that would not turn anything but bananas, with a couple of plastic squares. The test is putting them to together and into the light. Again I don't smoke( now) but I have cigarette papers as part of my measuring tackle. The spittle to hold them down isn't obligatory.

 

[rodw]

Being a simple soul, Children's plastic squares are as cheap as chips and after all, cutting a notch to avoid the saw kerf set is - or should be, obvious.

Except you can't raise and lower the blade through its entire travel to check for square like that. I know some of that is related to the accuracy of the pivot point but the adjustment of the blade plays its part too.