Weld Positioner Lash Up.

[Richiew]

Cheers Dapph, that's very generous. I would like to take you up on the Delrin offer. Will send you a PM. It will be a good excuse to cut a keyway on a shaft for the first time. I've used the mig, stick and tig, lathe, mill and soldering iron on this so far which is half the reason for making this really.

I had a good clear out of the cardboard boxes and other combustible things after I finished yesterday. It was making me a bit uncomfortable at the time but I hadn't planned on doing a lot of welding. All that stuff has been relegated to the shed. I think a further tidy up is in order.

 

[Richiew]

Little bit of progress. Tidied the garage out some more so I'm not falling over stuff. It becomes a nicer and calmer place to work in when I'm not tripping up. I got the Mig welder out. First time using it with a moving target so I used the previous pipe to plate coupon for practice rather than waste fresh material in short supply. I found I was running far too slow and the wire feed was too high to start with. I kept having to bump up the voltage too. That's my excuse for all the fat lumpy welds. I started welding around the inside of the pipe first as this hadn't been welded on. I finished on the exterior fillet but this was never going to be pretty as I was welding over previous stick welds.


The positioner definitely runs slow enough for Mig welding.

This is my last bit of pipe to plate. Got plenty of plate. Short of pipe. It got the proper shiney metal treatment with the flap disc. Ignore the holes in the plate, must have been part of a previous project. The hole in the middle helps keep the pipe concentric by eye.

Tacked up this time.

I ran a short weld conventionally without the positioner running to see that I was somewhere close to where I wanted to be.

All ready to go and find I've ran out of mig wire at the start of the first attempt. Initially thought I'd burned the wire back to the tip but soon realised there was no wire to feed through. Gutted.

Got some wire ordered and should be here by midweek. One good thing about working from home due to the virus is that I am always home for deliveries. Down to my last 50psi on the gas bottle too. Should be OK for a bit I hope.

Time to start on an arm rest. Don't need consumables for drilling and bandsawing.

 

[Richiew]

Arm Rest.

The top cross piece is bit of 40mm box. Used to be part of a weights bench. It is powder coated/painted grey. The two uprights used to be part of my niece's trampoline. I helped my brother dismantle it after wear and tear and the weather got the better of it. I kept all the galvanised tubes and the springs. First time I've actually found a use for any of it. It measures about 25.2mm which I suspect is 25mm plus the galv. The box section was drilled out to 1" so there is 0.1mm clearance around the tube roughly. The lower box section which is drilled straight through is 50mm square. The two horizontal pieces are both roughly 14" across.


I've seen people use round material for the arm rest but I think it might put a lot of pressure on a small part of the arm. I'm sure the contact patch is larger with flat material. Must be more comfortable?

I dug this out of the lathe materials pile. Will use it to make some locking collars on the lathe. To be welded to the 50mm box, threaded for a grub screw though the side. This will set the top height and make it adjustable. I've got plenty of spare bits of trampoline tube for replacements if necessary. They are fairly light gauged material and might deform due to pressure from the grub screws over time.

A clearer picture of what's been made. Mug and ruler for scale. I need to attach it the stand somehow. It needs to sit away from the turntable a few inches as it was too close when I offered it up. There's going to be some sort of connecting piece or contraption welded to the middle of the 50mm box section, probably with scope for adjustment if that does not make it all too floppy. There are two M12 bolts at top of the blue stand that I can use for attachment. They already connect the positioner frame to the stand but I can use them for the arm rest too if I employ some longer bolts. Finally I also need to keep the whole thing balanced so it doesn't topple over.

 

[Richiew]

Made a start on the collars tonight. Didn't have much time and I hadn't used this lathe in a while so I spent more time checking and inspecting rather than using it. It's a Henry Milnes/Denham DF4. They suffer with a lack of height between dead centre and the top of the compound so you can't get a decent tool post in there.

I've recently fitted a T37 toolpost to this lathe. A few weeks ago I bored out the tool post centre so it would fit the 1/2" BSW bolt that is poking out of the compound. I then had to make that long securing nut to hold it down. The hex is up in the air a bit so it doesn't interfere with the locking rotating bits on the tool post. There's not much spare space on the top of the toolpost, especially when you increase the bolt size from 7/16" to 1/2". There's just enough room so that everything that needs to can rotate. The tap snapped on the first attempt I made to make it.

It seems to work alright. The T37 is a bit Mickey Mouse compared to the 250 series type tool posts but it's fairly solid and beggars cant be choosers. The tool clamping screws are weedy but I haven't overtightened one yet. The locking mechanism is a bit faffy but it feels tight when it is all locked down. I had to shim the tools when using the old toolpost and it always put me off using it. This saves a lot of time.

I found a slightly longer piece of material to work with and cleaned it up.

Drilled out in stages to 7/8".

Bored out to a finished size roughly 25.5mm. I also faced the end using power feed to remove a ropey finish. It's still not very good. It was quite a lump of unsupported material so I kept away from the heady top speed of 660rpm and kept it down to 335 or 185 depending on the size of drill.

This is as far as I've got today. Parting, chamfering, cross drilling and threading to come next.

 

[Richiew]

Been plugging away at this for the last few days. Didn't have much luck parting the above piece off in the lathe. Never had any trouble before but this one kept breaking the parting inserts. I finished it off in the bandsaw. I've not parted such a large diameter before and the toolpost is new. I was also using the big lathe so quite a few new variables to account for. I had to finish it all off in the lathe again afterwards so its all good practice. I was really pleased with the pieces. One is a little bit taller than the other but I work slow enough without sweating dimensions that don't matter. The tubes move smoothly in the collars without too much wobble. I think I got the clearances about right.

I drilled out the collars. I had a bag of m10 grub screws. The label was worn and I thought the label said m10 x1 but it was actually m10 x1.5 so I used the wrong size tapping drill by mistake. The threads are still OK and hold the grubscrews fine. It made tapping a bit easier too as mentioned to me recently on here when I broke a tap.

Getting too old to be drilling on the floor. Need to make some sort of mount for this drill. 400kg and a fair bit of weight up top though. Wouldn't want it topple.

They were just set up by eye. If they were going to end up a little bit off it wouldn't matter. Pretty happy with them.


Dapph from this forum very kindly sent me some Delrin to make pulleys from. The collars are sitting on one of the pieces in the pic below. I'll make a bigger pulley for the main shaft. This will allow me to run the motor a bit faster which will be a bit kinder to it. Will probably give more surface area for the belt to grip and a greater range of adjustability all round.

Tapped by hand. No breakages.

The taller one is obvious here.

Continued...

 

[Richiew]

Convenient place to set up for welding.

Welds weren't great. This was my best one. I think maybe a bit less wire speed and move a touch slower. The tubes move smoothly through the collars still, so no heat distortion which is a win.

I found this piece of plate to mount the arm rest to the frame. It is diametrically opposed to the motor which is also a heavy lump so they balance out quite well

Ive drilled out two 1" holes for tubes to run in. I think they need to be drilled out further to get the tubes to slide. I've tried sanding the galv coating off the tubes to help with clearance bit they are still a bit sticky. I think the tubes drag on the holes more due to gravity in the horizontal orientation. They will always drag on the lower part of the hole I suppose. Ultimately the tubes will rest on the collars though. A brass bush might be considered.

I will make some more collars and drill two further holes in the bar I'm holding so I can get some in and out adjustment. Camera angle is not my friend here. The top tube isn't as high as it looks and the lower square tube is in line with the plate.

Rest of the goodies from Dapph. Lovely bloke. I will soon be attempting to turn Vee shaped pulleys, turn Delrin, turn using a mandrel, cut keyways on the mill and lathe, all for the first time. All good practice. If I get a thing out of it that will help me weld round objects it will be a pleasant bonus

 

[Richiew]

I've made two more bosses on the lathe and mocked up the arm rest. The bosses still need welding to the plate and I'm going to cut and drill some 3mm plate like a pair of spectacle frames to keep the two narrow bars aligned at the back. The bars needs shortening too.

I'm going to make some proper spacers for the two bolts covered in washers. The long bolts are quite practical as they catch and hang in the holes even when the nuts are removed so everything doesn't fall to the floor as I dismantle it. I want to protect the long threads from weld spatter using the spacers.


I haven't got round to making a new pulley yet but the mandrel has arrived.
I only broke one tap today. I didn't get it in square and it bound up on one side. The mistake sits at 6 o'clock so it can't be seen.
I need to start a drill sharpening program in the workshop. It's a joy to use sharp drills, especially in larger sizes compared the grief and time lost trying to use a blunt one.

 

[Richiew]

I've got rid of all those washers on the bolts. I found some 3/4" material and made up some spacers on the lathe. The bosses have been welded onto the plate. I didn't make a very good job of it as they weren't clamped down properly (At all) so one pulled a bit and they are now misaligned. The tubes trailing out the back give it away. Nothing has bound up despite this so it's OK.

The arm rest is now complete so there's no excuse not to attempt some welding.....












Ta Da!!!

My settings aren't perfect and need dialing in. I need to become less of a tightwad and buy some decent material so I have more to practice and experiment with. I have no problem buying tools but spending money on material always gets overlooked. The internal fillet weld has too much wire in it and it is rolling over on the bottom edge rather than wetting out.

The machine is doing its job. The arm rest is a Godsend for me, those tubes are far too long and need trimming. I'm still going to make a new pulley as it will be a new thing to try and I want to have a go a cutting keyways too. The wiring will get tidied up once the stop/start footswitch arrives.

 

[Richiew]

As Dapph was kind enough to send me some material it would be rude if I didn't use it in the build. I was originally going to turn it on a mandrel but I was in a "get it done" mood and the piece of Delrin was really thick so I could mount it in the lathe jaws and still have enough access to machine it. The V sides were cut with the compound set at 15 degrees and I then hogged out the middle.

I cut 3/16" keyway using a 3/16" bit of HSS in the carriage and just shaved bits off to depth. Possibly went a bit deep but I could always make a shallower key on the shaft.

The keyway was cut really long. The pulley is rather thick and a longer keyway gives a bit more range for the height of the pulley. Nothing has been measured or designed so the more flexibility the better to end up in the right spot. It also meant I could knock the key out from either end should the need arise. I used the table stop on the lathe to mill up to the same point with each pass which I found helpful. I found the centre of the bar using the balancing steel rule method. A DRO has since been ordered.

I should have moved the vice on the mill as the ways are exposed due to the table being too far over one side.

The bigger pulley works nicely. It slows the turntable so I can run the motor a little bit faster. I didn't machine the diameter of the delrin down and I've got about 3/4" between the outside edge of the pulley and the column stand so it worked out well. The key fits snugly with the aid of a hammer. I didn't want to make it too loose and I think I it's probably a bit on the tight side.

 

[Richiew]

The machine is now back together with the new pulley so I thought I'd a have try using TIG. I don't think TIG needs a positioner as much as MIG as I can avoid the cold starts that you get with MIG when I stop to reposition. This is 3mm plate. The weld sinks as the heat builds up but it is a promising start. 80amps 1.6mm wire. Blue Tungsten.

Few more attempts to get my eye in

110 amps 1.6mm wire Blue tungsten. Plate is 3mm I think the tube is too.

Tried again with a 2.4 wire. I can tell when I've got the motor speed too fast as the weld puddle just slides out the back, out of sight never to been seen again. The diameter of the part is very small I think it is 50mm at most. A large diameter part would need a lower travel speed which the machine can provide.

You might be able to see a couple of plates I made to keep the horizontal tubes in line. I think I need to make a wider arm rest if I want to TIG on this postioner as my left hand/arm is flapping in the air. The top bar is not wide enough currently.

I'm sure my settings and arc length could do with tweaking to make a better looking weld. I'm out of practice but I don't think it's a bad start.