HF Tool Grinder

[Paulsv]

I recently bought this tool grinder from HF:

http://www.harborfreight.com/1-2-half-hp-6-inch-tool-grinder-46727.html

I have a couple of newbie type questions:

1. It came with two green wheels, which have a metal plate on the back side, and then a ring-shaped grinding stone attached to the metal backing. They do a pretty good job of sharpening brazed carbide bits, but they are slow on HSS, and heat up the bits pretty quickly. Also, one of them seems to be out of balance. I'd like to try an aluminum oxide wheel. I checked Enco, but couldn't find that style of wheel. Can anyone tell me what that kind of wheel is called, and where I can get such wheels? What is the best way of trueing these wheels?

2. The table tilt mechanism is poor- it is hard to move the tables, becasue they bind. I have played around with the alignment of the parts, and gotten a little improvement. Does anyone else have this grinder, and do you have any tips on getting the table tilt mechanisms to work smoothly?

 

[Bill]

Paulsv,

I'm pretty much a newbie too.

I also had trouble finding aluminum oxide wheels for this grinder. I finally found some wheels at wholesale tool (www.wttool.com) for about $30 each. They called them metal backed cup wheels.

I had some issues with the wheel I bought from them. I only bought the one, and it was (considerably) out of balance, and the abrasive came too close to the holes where the mounting screws have to go - so I turned the screws down a tiny bit. I think I recall also needing to sand away the paint in the center hole for the shaft. (It's been a while and I've forgotten the details). It may have just been the luck of the draw. Most things I've bought from them have been fine. To be fair -- I don't know which was out of spec -- the wheel or the grinder - or both. It was just more fussing than I expected to get running. I (carefully) use a single point diamond wheel dressing stick to dress the wheel.

The tables? Mine are just as bad - I have to really loosen them up before I can budge them. I leave one side set square to the wheel (this side still has a green wheel), and the other at about 8-10 degrees. One of these days I should do something...

Hope it helps,
Bill

 

[Florian]

A bit late, but those grinding discs with the "green ring" are diamond discs and as you already found out usually used to sharpen carbide tools.

To get your hss bits sharpened, you need to look for a CBN wheel which is really good for sharpening hss bits.

Florian

 

[gunboatbay]

A bit late, but those grinding discs with the "green ring" are diamond discs and as you already found out usually used to sharpen carbide tools.

I think you'll find that "Green" grinding wheels are not diamond, but silicone carbide and, yes, are meant for grinding carbide tools. When used on HSS or other steels, they will glaze over very quickly and become almost useless for grinding anything until the glazed surface is removed by dressing them. That being said, the wheels that come with the HF grinder are a rather cheap quality of silicon carbide and should be replaced when time/finances permit.
CBN wheels are great, but very expensive. Aluminum oxide wheels are fine for HSS, are relatively inexpensive, and are available in a variety of grits. A coarser grit for initial shaping and fine grit for final sharpening, with a final touch-up by hand with a very fine hand stone or diamond lap.
There are fairly good diamond wheels available that will fit these grinders (e.g., cdcotools.com), but they are only for use with carbide tooling. If you use one of these wheels with HSS on your 3450 rpm grinder, you will permanently destroy the wheel's cutting ability in short order.

 

[fla Jim]

Here's a link to a thread i posted on another site about mods I made to my grinder:
http://www.shopfloortalk.com/forums/showthread.php?t=16899
also there's a link to Wholesale Tool for an AO wheel.

 

[doc1955]

I built a grinder similar to this and here is the wheel I use.

http://www.shars.com/products/view/5302/6x1quot_D6A2C_Diamond_Plain_Cup_Wheel

It has been a very good wheel but it is only for putting a fine edge on your tools it is for carbide but will work on high speed steel just have to remember it is only for honing a fine edge on your tools. For the price of this wheel it is a good buy. I am very happy with the preformance of this wheel.

 

[Florian]

I think you'll find that "Green" grinding wheels are not diamond, but silicone carbide
CBN wheels are great, but very expensive. Aluminum oxide wheels are fine for HSS, are relatively inexpensive, and are available in a variety of grits. A coarser grit for initial shaping and fine grit for final sharpening, with a final touch-up by hand with a very fine hand stone or diamond lap.
There are fairly good diamond wheels available that will fit these grinders (e.g., cdcotools.com), but they are only for use with carbide tooling. If you use one of these wheels with HSS on your 3450 rpm grinder, you will permanently destroy the wheel's cutting ability in short order.

Yeah, you're right; its even written on the HF shop...
But i often have seen diamond wheels which are green too; anyway...

 

[ken4570]

Here are a couple of links concerning the ubiquitous grinder.

http://bbs.homeshopmachinist.net/showthread.php?t=10497&highlight=hf+tool+grinder

http://www.shopfloortalk.com/forums/showthread.php?t=16899