Thread: Contact Wheels & Advice Please...

Ok, so I've jumped into it with both feet and have ordered a Polar Bear Forge "Grinder in a Box" today. This looks to be the most solid of the self made 2x72 grinders available.

Basically, I'm going to copy Brad's grinder...except for the color, sorry Brad...but THANK YOU for all of your input & advice.

I wanted to get an idea from you guys who have made some razors and used your grinders to make some suggestions on a couple things:

What two sizes of contact wheels?
I was thinking of a 3 or 4" and a 6 or 8"

Anyone got a spare they aren't using? Please PM me...

Where is the cheapest place to get them?

I'm on a budget and will more than likely "start" without a VFD and just go with a 1800rpm 2hp 220v set-up. Will probably use the guy mentioned on the PBF website for the motor unless someone points me into a better direction. I can/plan add the VFD later once the funds break loose a bit.

ANY experienced advice would be greatly appreciated.

Thanks in advance,
Scott

USA knifemakers Supply has poly tread wheels that are less expensive than the rubber ones. I have an 8 inch, and so far it seems to be fine. An 8 inch wheel will grind a 1/4 hollow. I have no experience with other sizes - I'll let someone with more time in grade comment on them. I do have a 2 inch rubber wheel at the top of my flat platten set up, so I can grind smaller radii when I have my flat platten set up on my KMG. I have a separate 1.5x1.5 bar for my 8 inch wheel.

I would watch Craigslist for a motor. 220v motors come up often, and for very cheap, since they are in lower demand. Check to see if there are any thrift shops dealing with construction items around your area -- I have one nearby that construction companies donate excess materials to when they finish jobs... They've always got electric motors in there for some reason...

I ordered my drive wheel and 8" contact wheel from Sunray.... and my tracking wheel and 4" contact wheel from USA knifemaker supply.. .but to be perfectly honest the wheels from usa knifemaker look absolutely identicle to sunray.. I cant see a difference. My sunrays run true as well...

Plenty of other places to get contact wheels though, shop around prices may have changed since I put my stuff together.. also I am not the best person to answer questions as I have limited experience thus far -- keep that in mind.

As for my paint color.... it was chosen by my son, so, in my eyes, it couldn't be better

USA knifemaker has Sunray make their wheels they offer. Difference is that with USA knifemaker you can order it and it's mostly always in stock.
With Sunray it will take about 3 weeks to get your order and if you have them balance the wheel(s) you will pay nearly as much for the balancing as the contact wheel itself. As to what contact wheels. I would say 4" and 8" strike a good balance in your setup.

Max pretty much covered the wheels. I have three sunray wheels 4,6,8 two of them are great one wobbles a bit.

I know the grinder in a box is set up for a direct motor mount, but you could put a flange mount bearing and rig a pillow block and put a step pulley there and run the grinder with pulleys. ( just thinking out loud)

Charlie

Thanks you guys! One more question on RPM:

Just ordered 8" & 4" contact wheels, tracking wheel, and a few ceramic belts...2-40 grit & 2-80 grit.

What do you think in regards to the rpm using a 1800 rpm vs a 3450 rpm, 2hp, motor and a 4" drive wheel?

I had considered the step-pulley system, but really plan on a vfd. I've seen a few on the bay for a couple hundred and am sure there are other suppliers (something other than Chinese) in that price range.

There are no locations that I am aware of that I can pick up a used motor, so I'll more than likely go with a new one...shoot, the fuel to a place that I could pick up a used motor (Dallas is the closest that I can think of other than Sherman, TX) would make up the difference of a new one (my truck gets about 16 mpg & the bike only gets around 30). Then we have the most cherished thing...time. If I take the wife to either of the places, then we have to hit a steakhouse...so it's definitely cheaper to mail order...

I went to a local used sport and exercise equipment store, and the gave me, free of charge, a treadmill they were throwing in the dumpster. It has a 2 1/2 hp, variable speed, DC motor. I made it work on my KMG grinder. It looks a bit odd, because I had to use the treadmill control panel to get the variable speed, but - free variable speed motor. My step daughter jokingly wants to know which of the programs (climbing hills, running beaches, etc.) I use to grind a razor. Now what can I use the motorized incline jack for------?

Originally Posted by shooter74743

Thanks you guys! One more question on RPM:

Just ordered 8" & 4" contact wheels, tracking wheel, and a few ceramic belts...2-40 grit & 2-80 grit.

What do you think in regards to the rpm using a 1800 rpm vs a 3450 rpm, 2hp, motor and a 4" drive wheel?

I had considered the step-pulley system, but really plan on a vfd. I've seen a few on the bay for a couple hundred and am sure there are other suppliers (something other than Chinese) in that price range.

There are no locations that I am aware of that I can pick up a used motor, so I'll more than likely go with a new one...shoot, the fuel to a place that I could pick up a used motor (Dallas is the closest that I can think of other than Sherman, TX) would make up the difference of a new one (my truck gets about 16 mpg & the bike only gets around 30). Then we have the most cherished thing...time. If I take the wife to either of the places, then we have to hit a steakhouse...so it's definitely cheaper to mail order...

1800 or 3450 rpm?

I do not know what rpm motor, it depends on drive wheel and VFD, I tend to grind pre heat treat about 2700 fpm and post heat treat about 400 fpm.

Charlie

Thanks for the reply! I totally forgot the FPM math. I have a feeling that with a 4" drive wheel, the 1800 rpm would be closer...just couldn't post treat grind with it until I got the vfd or did some sort of pillow block system & pulley's. Do you feel that your system is fast enough?