Welding Tips and Tricks

Hi Guys, I need to weld a 2" dia shaft to a 1/2" steel plate. It will be used for a Band saw mill. The 16" long shaft will be laying flat on the 12" sq plate hanging out 4" holding a 25" dia band saw wheel.

What kind(s) of welders do you have?

Preheat and watch your interpass temps. It’s easy to get it too hot. Plus space the rod off of the shaft to start. It will help with the warping of the plate a little. How flat does the plate need to be when your done?

I have access to both tig & mig Miller welders 300 amp, the plate will need to be flat when done. pic attached I could weld the plate to the 8 x 8 tube first?

Welding the shaft to the plate while keeping it flat is going to be hard. You could try making the plate out of two halves. Bevel them, fill the groove then grind the weld flat.

Or use a thicker plate and machine it flat after welding

I think if you weld the plate to the 8x8 first, you’ll greatly reduce any chance of warpage.

Now, the trick to welding the shaft to the plate.... any option to run the shaft through the 8x8 instead? That would allow you fillets between the shaft and the 8x8. Then cap the end with the plate.

I was thinking about running the shaft thru the 8 x 8 when I was uploading the pic of the assembly. There are some die springs needed for tensioning the blade that sit behind the plate. I will rework the model and see if they would work with the shaft inboard of the plate. Thanks

If you weld the shaft onto the plate it makes it hard to replace if the idler wheel bearings / bushes create wear on the shaft & the width in the center of the wheel in proportion to it's diameter looks kind of narrow giving a good chance of play which will cause blade chatter / finish issues - could the wheel not be solid on the shaft & pass through 2 pillow block bearings bolted onto the 12" plate - I think that may work better & requires no welding .

The idle wheel comes with 2 bearings, I could buy a second drive wheel it comes keyed with a 2" shaft, then I could possibly use pillow blocks on both drive wheels. That would make replacement easier.

If you already have the wheel then go with it - it was only a thought if you were still at the planning stage - if you do use the wheel with integral bearings you could still do a similar idea by using a split block bolted to the plate that clamps the shaft - such as old plumber block bush style bearings - recycled big end caps if you find some close to size or can bore to size - make some if you own a milling machine or ( don't laugh ) the split nylon blocks used to secure rigid steel hydraulic pipes - these are available in a huge range of sizes & are way stronger than you might expect - I use them for all sorts of projects.

Still in the planning stage, I do have 4 - 2" pillow blocks that I can use. So I guess I will order 2 of the drive wheels, should be the best way to go. Thanks

Hope it works out - I nearly built a saw mill a few years back as I was getting some big timber for free but sadly it dried up when the guy got ill & quit dropping trees for a living so I never got to do it - I'll be interested to see your build - I only end up with moderate size & diseased stuff now so only saw logs - always fancied doing one of those resin / river tables - I think the wider spaced bearings may reduce vibration giving better cut quality & blade life - you building from plans / taking inspiration from YouTube stuff or free lance ?

I am drawing my own plans, YouTube plans and designs were a little "weak" so I went to the bandsaw mill websites and got some ideas from them. I saw a lot of design flaws especially with the log clearance. I am interested in being able to quartersaw the logs and most of the mills I have seen can't cut a log in half. I'll keep adjusting my design until I'm happy with it. Thanks

I’ve done a little boiler work at a local saw mill and talked with one of there maintenance guys about there saws. They get special filler wire from the blade manufacturer for repairing there broken blades. They break fairly often due to the tight radius of there guide rollers and the tension. Any chance you could use larger diameter rollers?

I am planning on using 25" wheels so I can use a thicker blade .050" and hopefully won't break.

It’s a guaranteed eventuality. Leave yourself plenty of adjustments for running an ever shortening blade.

msmithblues wrote:I have access to both tig & mig Miller welders 300 amp, the plate will need to be flat when done. pic attached I could weld the plate to the 8 x 8 tube first?

Strongly recommend against welding a ROUND member directly to a FLAT plate. You will not achieve adequate fusion in the interface between the ROUND member's tangent point to the FLAT steel plate. Simply stated, this is weldment design geometry you want to avoid. And we haven't even mentioned the potential for excessive warpage due to Mr. Heat Shrink.

Guarantee you will not achieve root fusion as you 'shoot the gap' and attempt to TIG/MIG/SMAW the joint in that constrained geometry.

This is a classic NoNo for fabrication, and highlighted in AWS literature by the late Lincoln Electric wizard Omar Blodgett and others since the 60s.

Change your approach. Instead, use pillow blocks or standoffs......as previously mentioned.....to affix the ROUND member to the standoff and then the standoff to the FLAT plate. Think: insetting the ROUND member into the "U" of a C-Channel.

You want the tangent of the ROUND bar to meet an interface without excessive "gap".

DM me if you need additional insight.