Components

[PeterT]

so many ways to skin the cat, but I guess a picture doesn't say how they operate without seeing feedback.
My eye wants to see torsional rigidity on this floating arm component

 

[Dabbler]

That's what I was thinking, 800$ for 100$ (if that) worth of plate, that's a pretty good markup, I'm in the wrong buisness

I get it. But there is a reason why people are still buying 2700US$ grinders.... it isn't because they are profligate with their money... There have been 4 or 5 startups to my knowledge that sold complete 'flat kits' - all the plates laser cut or waterjet cut to make one - in the 400$-600$ range. Most of them are gone. And many guys just don't have the skill or tme for a new project - they just need a grinder, "now"..

I think I'm going to build one from some 1/2" plate I have in the 'yard'... but I don't own plasma, waterjet or laser. So I'll have to forgo all those fancy designs and (sigh - or is it 'yay'?) design it to suit my materials.

I refuse to spend that 1000+$ for grinder bits when I have 2 6X48 grinders. So mine will have to be on the cheap-cheap to be attractive to build. I did buy the odd roller and keep an eye on other parts, with the intention that I might build one!

 

[Dabbler]

My eye wants to see torsional rigidity on this floating arm component

Often the least rigid part of the arm for torsion is how it is attached to the frame. A weakness in many designs, in order to keep it simple, or no-weld, etc...

 

[TorontoBuilder]

I guess context is everything. I quoted some stuff last year, and, well, waterjet is waaay out of the question around here. 35" of cutting 1/2" plate: 300 dollars. I don't get it.

It used to be stupid sick price in Toronto. Not as bad as when I had no choice but to do laser cut. That was so bad I was willing to hand cut parts.

It really comes down to how many metal suppliers you have and how many bought a waterjet to add to their line of services. We now have a handful of good vertically integrated companies. They want to sell you then metal and cut and bend it etc. Thankfully I now have an east end GTA supplier so I don't have to go to the west end and longer.

If I was in region where prices were still high, I'd create buying pool and get commercial account at one supplier. save up and submit group orders to get better pricing.

 

[Dabbler]

That was so bad I was willing to hand cut parts.

So my solution is to design it for the vertical bandsaw. Don't care if I got through 2 blades at 80$, and the time to save that extra 500$

 

[TorontoBuilder]

I get it. But there is a reason why people are still buying 2700US$ grinders.... it isn't because they are profligate with their money... There have been 4 or 5 startups to my knowledge that sold complete 'flat kits' - all the plates laser cut or waterjet cut to make one - in the 400$-600$ range. Most of them are gone. Am namy guys just don't have the skill or tme for a new project - they just need a grinder, "now"..

I think I'm going to build one from some 1/2" plate I have in the 'yard'... but I don't own plasma, waterjet or laser. So I'll have to forgo all those fancy designs and (sigh - or is it 'yay'?) design it to suit my materials.

I refuse to spend that 1000+$ for grinder bits when I have 2 6X48 grinders. So mine will have to be on the cheap-cheap to be attractive to build. I did buy the odd roller and keep an eye on other parts, with the intention that I might build one!

I'm the antithesis of profligate.

If I didn't have an autoimmune disorder trying to kill me and terrible arthritis as a result I'd hand cut my parts and clean them up on various machines. A die filer would make it super easy and even let me use mortise and tenon technique.

I may just do that anyway for my next batch of plates to make more etching presses.

 

[phaxtris]

Why would you pay for water jetting on something like this, a plasma would do a perfectly acceptable job, at a much cheaper price

Most bigger steel suppliers have a "fab shop" that does CNC cutting usually flame or plasma

Or there are the hundreds (or so it seems) garage guys that cut signs out

It could all be done by hand as well

 

[TorontoBuilder]

So my solution is to design it for the vertical bandsaw. Don't care if I got through 2 blades at 80$, and the time to save that extra 500$

My brother and I bought 3 portable band saws just for this purpose... and I copied grunblau designs band saw stand to set one up permanently as a vertical band saw. If your parts are not too large it is a viable route for frugal people

 

[TorontoBuilder]

Why would you pay for water jetting on something like this, a plasma would do a perfectly acceptable job, at a much cheaper price

Most bigger steel suppliers have a "fab shop" that does CNC cutting usually flame or plasma

Or there are the hundreds (or so it seems) garage guys that cut signs out

It could all be done by hand as well

For myself, my plasma cutting guy's machine is not capable of cutting the required thickness... or so he says. He is a sheet metal guy and doesn't stock plate.

There is much to be said for single source supplier and my water jet service is competitively priced with plasma services.

And finally, the finish and dimensional accuracy allow for minimal post cutting finishing, I just chamfer edges, ream or tap some holes without any drilling. The edges are not hardened from hot cutting either so easier to work.

These are plates I use to make small etching presses. The hole alignment is perfect, the finish is good enough that I only need a light sanding in the take-up bearing slot in order to install the take-up bearings. Ream or tap, chamfer, sand, prime, paint and assemble. If you plan to assemble with a mig welder you can simply run a grinding wheel brush over the areas to weld and be ready to weld in seconds. Tenons drop right into mortise holes easy peasy

3 plates stacked together. holes align perfectly

 

[phaxtris]

A properly set up plasma table with a good plasma can produce accurate parts, I would say withen .01, smaller holes can be a problem, of course the edge is not quite as nice, but I wouldn't pay the extra for water jetting unless there was a very good reason. For something like a belt grinder water jetting is way way overkill in my opinion

 

[Chris Cramer]

Not intending to be critical of the design, more an observation. This vertical component holding the idler wheel looks like it could be prone to bending side to side & that could cause tracking issues. Other designs seem to have a very beefy arm or it's integrated directly into the frame & only the axle changes angle slightly if I understand the mechanism correctly. Maybe before you toss your design, consider an upgrade in this particular area like square tubing or something more rigid?

Unless you are saying its just time for something new. I spent some time a while back collecting ideas & prices & plans but its an official back-burner project. The kit & commercial prices are up there & if anything getting worse with FX & shipping. If you got hold of some plans you like, you could get the parts water/laser cut. Yes they charge money, but shipping steel across the country has a cost too. I think Clough42 mentioned his SendCutSend parts + motor/vfd + wheels etc. ended up costing 2K (I might be off, watch the video). But that's USD & not sure if that was his incentive price etc. But he wanted his machine with his design features so it was worth it to him. A lot of guys don't have welding facilities which many of the kits require even though they have nice interlock tabs to help with alignment. I haven't seen too many 'bolt-together' only designs but I'm sure it would be comparably rigid if designed properly. Good luck!

View attachment 31808

Yeah, I have been thinking about designing a tensioner that is pressed straight up from a square tube rather than a lever. The arm I have installed has a flat bar on both sides of the wheel and is connected to the outside of the center tube to keep it straight. However, the arm got twisted somehow, so I want to have a tube slide out another one with the Gas spring set underneath to press the belt straight up.

 

[Chris Cramer]

A properly set up plasma table with a good plasma can produce accurate parts, I would say withen .01, smaller holes can be a problem, of course the edge is not quite as nice, but I wouldn't pay the extra for water jetting unless there was a very good reason. For something like a belt grinder water jetting is way way overkill in my opinion

I agree, even for the most common reason for waterjet instead of plasma cutting (to avoid heat) I don't find it is enough to say it should not be plasma cut. I have all the parts and equipment to fabricate a new machine, I have a CNC plasma table to cut the plates, a multi process welder, the track wheels, drive wheel, contact wheel, motor, and VFD. It is all about the extra time it would take to build a new machine from the beginning. If the improvement on the tensioner does not work, then I would most likely start over.

 

[phaxtris]

If your going to re-design I would look for a face frame motor to use, the whole one plate bolt everything to it makes the whole design very easy, and no alignment issues to screw with

Or you could figure out how to bolt your motor on as a face frame, I have seen that done with a foot mount style before, it really does solve a lot of problems doing it that way

 

[TorontoBuilder]

A properly set up plasma table with a good plasma can produce accurate parts, I would say withen .01, smaller holes can be a problem, of course the edge is not quite as nice, but I wouldn't pay the extra for water jetting unless there was a very good reason. For something like a belt grinder water jetting is way way overkill in my opinion

It comes down to if people really "pay extra" or not. I'm sure that most people likely do to some extent but I don't pay more than a 5% premium. a few bucks more for a set of parts that require less work is nothing

Or will you have to many holes etc that you want to tap with small diameters, or holes that you want to ream and dont want hardened holes.

I agree, even for the most common reason for waterjet instead of plasma cutting (to avoid heat) I don't find it is enough to say it should not be plasma cut. I have all the parts and equipment to fabricate a new machine, I have a CNC plasma table to cut the plates, a multi process welder, the track wheels, drive wheel, contact wheel, motor, and VFD. It is all about the extra time it would take to build a new machine from the beginning. If the improvement on the tensioner does not work, then I would most likely start over.

yeah, when you own a plasma cutter it is a no brainer.

however, the parts cutting comments were not specifically in relation to a belt grinder build, and were in reference to markets where the price differential is minimal, within 5%. There are many other builds where waterjet is better such as a welding table top with a large number of grid of holes for bench dogs and clamps that required no extra work to finish.

 

[TorontoBuilder]

I agree, even for the most common reason for waterjet instead of plasma cutting (to avoid heat) I don't find it is enough to say it should not be plasma cut. I have all the parts and equipment to fabricate a new machine, I have a CNC plasma table to cut the plates, a multi process welder, the track wheels, drive wheel, contact wheel, motor, and VFD. It is all about the extra time it would take to build a new machine from the beginning. If the improvement on the tensioner does not work, then I would most likely start over.

OH I forgot to say... since you have a cnc plasma cutter perhaps you can cut plates for locals? I'd be happy to send you a dxf file for parts if I can get the the right kerf to design to.

 

[phaxtris]

I'm not trying to start a fight, so don't take it that way, but If you are only paying a 5% premium for water jetting over plasma cutting something is wrong with the price your getting for plasma cutting, water jetting is considerably slower and more expensive (media) than plasma

If the best price I could get for plasma was only 5% lower than for water jetting I would go that way also, but I know for sure, 100% that I can get a part made by plasma considerably cheaper than by water jetting


My bet on why your only 5% cheaper for a plasma part, whoever you're using is not getting a good rate on steel, and has to make it up somewhere, not there fault, you need to buy in the millions $ a year range to even get a half decent rate...and it's still not that great at a mil$

Like I said before, most big suppliers (aka varsteel) have there own fab shop that exclusively do CNC cutting, braking, shearing, etc. Unless your buying millions worth in a year they are usually hard to beat for price...sometimes you can hardly buy the plate for what they sell cut parts for

 

[Chris Cramer]

OH I forgot to say... since you have a cnc plasma cutter perhaps you can cut plates for locals? I'd be happy to send you a dxf file for parts if I can get the the right kerf to design to.

My machine torch consumables can cut to a kerf width of 0.04" with fine cut, and 0.06" whith a machine nozzle for thicker stock. Mild steel can be severed as thick as 1" and clean cut as thick as 5/8". Stainless can also be cut as thick as 5/8".

 

[Crosche]

I agree, even for the most common reason for waterjet instead of plasma cutting (to avoid heat) I don't find it is enough to say it should not be plasma cut. I have all the parts and equipment to fabricate a new machine, I have a CNC plasma table to cut the plates, a multi process welder, the track wheels, drive wheel, contact wheel, motor, and VFD. It is all about the extra time it would take to build a new machine from the beginning. If the improvement on the tensioner does not work, then I would most likely start over.

Chris, @phaxtris has a pretty straight forward grinder and mine is very simple too. Perhaps the three of us could meet at my shop or @phaxtris (if he isn't busy) and get your grinder running.

 

[Chris Cramer]

Chris, @phaxtris has a pretty straight forward grinder and mine is very simple too. Perhaps the three of us could meet at my shop or @phaxtris (if he isn't busy) and get your grinder running.

Thanks Crosche, tha would help me get a good idea of how your track wheels are setup, and how the chasis is built.

 

[phaxtris]

Yea I'm open to that as well If you like @Chris Cramer