2x72 Grinder project

[wquiles]

Started thinking/planning about it when my crappy 2x72 cobbled up grinder motor died in early Jan 2021, and I started actual welding in March 2021. I still have to weld the work surface to the work arm this coming weekend, and re-do the belt covers (I burned through the thin metal!), but it is actually running now: Baldor Industrial 3PH, 3HP motor with an VPF

Started by removing the inside weld seam in a couple of square tubing pieces:





Although I did make most everything from scratch, I did buy the "C" bracket assembly from Origin Blade Maker. Since it is my own design, I have no plans - I adjusted as I went along. Here I am clamping everything to get an idea of spacing, length, etc..



Cut and milled the top arm, and even made some delrin spacers for a slight press fit:






This is the mockup (clamped in early April):




Once I figured the spacing to get all wheels aligned, I started welding - 100% with my new to me HTP 201 water-cooled Tig Machine:

 

[wquiles]

Welded a spacer for the rear to hold the two pillow bearings:





Bought several springs trying to find the "right" amount of tension:



I wanted a handle at the end, so I capped the movable arm:




Note the adjustable/trim piece for the top wheel I also got that assembly from Origin Blade Maker:

 

[Ian]

100% duty cycle must be nice. You making knives now?

 

[wquiles]

Main body welded - another mockup with clamps:


How I tested various springs:


Fitting the drive wheel:







Custom delrin to get spacing perfect against the bearing:



For the base, I used a scrap piece of about 1/2" I found while doing cleanup with my son's Boy Scout camp in a local creek:



Took a lot of sanding to get the bulk of the rust:


And then vinegar (works great to remove mill scale!):

 

[wquiles]

Welding the main frame to the base - all of this square tubing is 1/4" wall:




Occasionally I got a decent looking Tig weld:



Then started working on the stand:

 

[wquiles]

Mockup of the grinder on the mobile base:




To being able to do small adjustments on the spring for the top arm, I made up and welded this small piece:








I was initially going to make a movable arm for the VFD from scratch, but found a $20 brand new arm - hard to pass up:



Made and welded a simple bracket to hold the VFD:

 

[wquiles]

One side:



other:



When wire the motor and VFD. Got lucky and got the right direction (50-50 chance):

 

[wquiles]

Still need to weld this piece this coming weekend:



But here is the running grinder/stand:





My first Tig project. About 4 months, done a little bit every weekend

 

[wquiles]

100% duty cycle must be nice. You making knives now?

Opps - you replied as I was still posting pictures. Sorry I missed it.

Yeah, the crappy welder I had cobbled up was a combination of a 2x72 ebay grinder and a 1/2HP bench grinder, with a few pieces from a prior 2x36 Multi-tool attachment:
link

I know that a 1HP would be OK, 1.5HP would be great, and 2HP would be supper, but I already had the 3HP baldor - and why not? Right? . Plus with the VFD, I can really go slow/fast without risking stalling it - which happened to me often with the 1/2HP motor (assuming it was actual 1/2HP - which I doubt!).

I have made some knifes and tools for myself in the old one, plus I used it for all welding projects, so when it "died", I decided to go all out and make something I would probably never have to worry about wearing out. I also wanted it with the off-set motor mount, with plenty of shelve space, etc. - I wanted to fix/improve on all of the things I hated about my prior setup.

It was a serious overkill to use 1/4" wall on the main grinder/legs but I had the steel on hand already - same as the motor, so my only significant expense was the VFD, about $40-50 for the 1/8" wall steel for the bench/stand, about $50 for the casters, and about $150 from the parts I bought from Origin Blade Maker. Mabe add another $40-50 on screws, cable, conduit, etc. - it was not an expensive project to make, but certainly time consuming and a GREAT learning experience with my new to me Tig setup.

 

[KeithB]

The welds look pretty darned good to me!

 

[CWLONGSHOT]

I have been a Certified welder for a lil over Twenty years now. Oddly its what I wanted to do when I was in High School but took almost twenty years to find that out!! Hahaha I have never TIG welded. Its something I have wanted to do but its not something we need on the jobs I have.

There is an amount of undercut on some of the welds but you surely have penetration!! Love fabing things like this so thanks for sharing!!

CW

 

[Ian]

Better than my first TiG welded project, for sure! I see a lot of MiG and stick fitting habits not ideal for TiG being used, i.e. big fillets and gaps and thus trying to do more in one pass than is ideal for the high heat/low fill nature of the TiG system. Old habits die hard! I do like to be able to tack stuff together without a bunch of cold, lumpy globs of weld though, then go back with one or three passes with enough filler and not so much heat as to get those undercuts. I think most of us learn on other systems and are taught to focus on getting burned in well and getting the heat down in the joint while managing what is inherentlyTOO MUCH filler material...then we pick up a TiG torch later on and start burning holes in stuff. TiG is a challenge in many ways, lots of new things to learn and master all at once, feels like juggling a dozen plates while walking a tightrope until muscle memory starts to develop.

 

[wquiles]

Thank you!

I started Tig on the grinder frame, and finished on the stand - by the time I was doing the stand, the Tig welds were starting to look better. As I do more Tig projects, I will get better. Practice, practice, practice.

My mentor insisted I take a welding class, and I did, and I am glad I have been welding for many years with MIG before I started Tig. The fundamentals I learned in class, those basic prep steps, watching the puddle, comfortable position, doing a dry run to check travel, etc., come really handy when switching to Tig. Even though Tig is more demanding on cleanliness, prep, and on keeping a tight arc, I actually enjoyed Tig a lot more than MIG as I feel I have more control with Tig. I feel that MIG is definitely faster and simpler to learn, and I would likely never recommend to a new welder to start with Tig - too many variables to try to learn at once.

 

[Ian]

There's a reason stick is taught first. The squirt gun is too easy to make pretty, but cold-started and superficial welds and the TiG is just a MF'r if you're new to the practice of gluing metal together with fire.

 

[KeithB]

I learned to gas weld first, then stick, then MIG, TIG last of all. To me TIG is a lot like gas. I lack the physical coordination to ever be a good welder, that's probably why I greatly admire the welding skill some folks have.

 

[CWLONGSHOT]

I started with the buzz box and then gas. MIG wasnt as popular of coarse then onto mig. Im on my third mig machine @ home and atill my first old Lincoln buzz box. Took to ARC and MiG quickly, but gas took a lil more time. I really enjoy the fab work. Biggest thing Im missing healin up this damn knee...

CW

 

[Tomme boy]

Welds look good. But definitely need to go back and run more filler into most of them. The welds that are deep need to have 2 more passes on each one. One that covers the top half and the second to cover the bottom half. My teacher would then have you do either a single large cover pass or 3 separate welds to cover it. Post #5 pic #4 needs some of the most work. That is a root pass. Now it needs the other passes I mentioned. It looks good just needs more.

I'm ot trying to be a know it all. Lots of people here are better than me at most things. I envy you for jumping head first with tig welding. It is one of the hardest to get good at. I was good at arc and mig, fair at tig.

It's been 20 years sense I last ran a tig. Everything I do now a mig is good enough.

 

[wquiles]

Cool - thanks for the detailed feedback on improvements. I did play a little with making multiple passes with Tig, and we did practice that on the welding class, so I get what you mean. To be 100% transparent, for this grinder stand I am not worried about leaving the root passes "as is", but I do hear you loud about these not being as strong as they can be with just the root pass - thanks. One of my future projects is potentially making a single piece lathe stand (1500+ pounds), and there I can't risk it - I will certainly heed your advice and do the additional passes

 

[Ian]

Tomme nailed it, basically what I was getting at with heat/filler and method of delivering the fire, TiG is relatively hot and low-fill. TiG is one tool, probably not the tool of choice for gobbing together mild steel with big seams. I'd do your project with MiG even having all the other tools, mainly because it would be fast, strong, and the welds would look great with the material and joint fit you were working with. If doing it with Tig for the hell of it and practice, I'd fit the joints much differently than you did and make a single pass on everything for appearance. The result would be only about 40% penetration and relatively small weld seam width but plenty strong for the grinder.

Fit-up for Tig is a specific technology unto itself, and different from how you'd fit for other welding methods. Basically you fit your joints to optimize the strong suits of the welding method you choose, TiG's being lack of flux and having absolute and separate control over the heat and the filler. I'd also back-purge the joints. But.... Like most everyone else here, I'm no weldor and didn't even stay at a Holiday Inn last night, so you carry on!

 

[fiver]

it'd all get stick welded if I were doing it.
MIG is fine if your putting 2 pieces of sheet metal together, but I'd just reach for the 110 buzz box there too.
mostly since that's what I got, and what I learned on.