Page 1 of 2 12 LastLast
Results 1 to 15 of 16

Thread: slow speed grinder ?

  1. #1
    Join Date
    Apr 2011
    Location
    wisconsin
    Posts
    187

    slow speed grinder ?

    been looking at slow speed grinders woodcraft has one that runs at 1750 penn state has one that is two speed 3450 and 1750 lowes has a porter cable that i really like it is also 2 speed. but the lowest speed is 2000 rpm. is this slow enough for sharpening my gouges and skews ect? has anybody had any experience with the porter cable grinder pros and cons. any other suggestions/ thanks guys
    cal
    Grandpa always told me. "A good woodworker is not one that makes no mistakes. A good woodworker is one who knows how to cover up his mistakes."

  2. #2
    Join Date
    Oct 2011
    Location
    Colorado Springs
    Posts
    747
    Cal, Woodcraft has a no name 8" 1750 rpm grinder with two white wheels which is often on sale for around 100. The wheels which come with most grinders are probably not suitable for turning tools and good wheels will add a lot to your total cost. Don't know about the Porter Cable in particular. If you have a choice, go with an 8" grinder.

  3. #3
    Join Date
    Nov 2007
    Location
    Fort Pierce, Florida
    Posts
    2,585
    If I understand correctly, Black and Decker owns the Porter Cable brand and did own the Delta brand. Since selling off Delta, I have noticed that Porter Cable seems to be filling the niche that Delta had, at least in the smaller (sub $1000) machines. I think it is possible that this is the same grinder that used to sell as a Delta grinder, in which case it is a good machine and I have had one for a couple of years. It looks VERY similar, except for the 'tool-less' nuts to hold on the wheels.
    Retired - when every day is Saturday (unless it's Sunday).

  4. #4
    Join Date
    Apr 2007
    Location
    Georgetown,KY
    Posts
    1,106
    What makes the Woodcraft low speed grinder a hard to beat deal is the fact that it comes equipped with the Al Oxide(white) wheels already installed, and the other brands are most often equipped with gray wheels not well suited for HHS tools. Buying white wheels separately often costs more than the Woodcraft grinder.

  5. #5
    Join Date
    May 2010
    Location
    Stow Oh.
    Posts
    1,583
    The PC brand name has been sold to the Chinese and the product has turned into a nightmare because you don't know if it's like Thom said an old Delta or a new Chinese junk. Really look at the tools being sold in Lowes,HD or any box store under Porter Cable name and really look before you buy any.
    Comments and Constructive Criticism Welcome

    Haste in every craft or business brings failures. Herodotus,450 B.C.

  6. #6
    Join Date
    Nov 2006
    Location
    Tulsa, OK
    Posts
    70
    Quote Originally Posted by Harry Robinette View Post
    The PC brand name has been sold to the Chinese and the product has turned into a nightmare because you don't know if it's like Thom said an old Delta or a new Chinese junk. Really look at the tools being sold in Lowes,HD or any box store under Porter Cable name and really look before you buy any.
    Porter cable is still owned by Stanley Black & Decker. They did sell the Delta brand.
    1060 Miles Southwest of Steve Schlumpf

  7. #7
    Join Date
    Dec 2008
    Location
    Cary, NC
    Posts
    282
    Cal, I have the PC from Lowes and I fitted it with the D-Way CBN wheels and it works great.

  8. #8
    Join Date
    Nov 2007
    Location
    Littleton, CO
    Posts
    22
    I looked at the PC several years back, but ended up going with a Craftsman 8" variable speed. It was a little more, but it is 1725 - 3450 rpm as opposed to 2000 - 3400 rpm. It does come with one wire brush and one gray wheel though, so plan the expense of new wheels. Overall I have been very happy with it. As Doug said, 8" is the way to go if possible.

  9. #9
    Join Date
    Nov 2009
    Location
    Englishtown, NJ
    Posts
    44
    I agree with all previous posts. I've had the Woodcraft slow for over a year and find it quite adequate. I'd used a Jet slow/wet for years (10" wheel), and a high speed six inch for shaping. Space became a problem and I substituted the Woodcraft slow 8" for both. No matter which grinder you buy I suggest you get new wheels, although the white wheels on the Woodcraft are decent. I see no need for the dual speed, it really doesn't speed the reshaping of a tool as the higher speed means you have to take more time out to cool the tool. In the days of carbon steel tools the cooling could be instant by dipping them in water - but the HSS steels don't like the rapid cooling, it changes the crystaline structure of the edge (or so I'm told), so I see no reason for the higher speed on an 8" wheel. BTW, for those on 6" wheels, remember that the rpm of the shaft isn't the same as the speed of the wheel surface. The speed of the wheel surface on the tool is feet per second (or millimeters per second) - it is a linear measure. A wheel of a circumference of 3 inches (we'll use circumference rather than getting involved with Pi) spinning at 60 rpm has a linear speed of 3" per second. At the same 60 rpm a 6 inch circumference wheel has a linear speed of 6" per second. It is the linear speed that grinds the tool, and heats it - not the rpm.

    Best, Jon

  10. #10
    Join Date
    Nov 2007
    Location
    Fort Pierce, Florida
    Posts
    2,585
    Quote Originally Posted by Jon Murphy View Post
    I agree with all previous posts. I've had the Woodcraft slow for over a year and find it quite adequate. I'd used a Jet slow/wet for years (10" wheel), and a high speed six inch for shaping. Space became a problem and I substituted the Woodcraft slow 8" for both. No matter which grinder you buy I suggest you get new wheels, although the white wheels on the Woodcraft are decent. I see no need for the dual speed, it really doesn't speed the reshaping of a tool as the higher speed means you have to take more time out to cool the tool. In the days of carbon steel tools the cooling could be instant by dipping them in water - but the HSS steels don't like the rapid cooling, it changes the crystaline structure of the edge (or so I'm told), so I see no reason for the higher speed on an 8" wheel. BTW, for those on 6" wheels, remember that the rpm of the shaft isn't the same as the speed of the wheel surface. The speed of the wheel surface on the tool is feet per second (or millimeters per second) - it is a linear measure. A wheel of a circumference of 3 inches (we'll use circumference rather than getting involved with Pi) spinning at 60 rpm has a linear speed of 3" per second. At the same 60 rpm a 6 inch circumference wheel has a linear speed of 6" per second. It is the linear speed that grinds the tool, and heats it - not the rpm.

    Best, Jon
    Lets look at real numbers:
    8" dia @ 1720 = 8 x 3.14 x 1720 = 43206 in/min --> That is almost 41 mph (multiply by 60/12 [or 5] to get ft/hr and then divide by 5280 to get mph)
    For a quicker estimate 8 x 1720 / 337 is close enough.

    8" dia @ 2000 -> 47mph - not too big a change, a little wear on the wheel will bring that down anyway
    6" dia @ 1720 - reduce first number by 3/4 (6/8) --> 30 mph
    6" @ 3440 - double that - 60mph

    Not too many 6" low speed grinders are available, and at 50% faster than an 8" slow speed a HS grinder cuts too fast and generates too much heat.

    My 8" dia wheel is now about 6" and my old 6" grinder has a wheel that's about 4 1/2" They don't work as well as they used too and the curvature of the hollow grind has visibly changed. About ready to move the old 8" wheel to the 6" grinder and replace it with a CBN wheel.
    Retired - when every day is Saturday (unless it's Sunday).

  11. #11
    Join Date
    Apr 2011
    Location
    wisconsin
    Posts
    187
    Thank you all for the information. Still undecided what i am going to do. wood craft is out of stock till end of november. If I decide on the porter cable and have to purchase two new wheels would I be best off getting 2 120 grit wheels or like the wc grinder comes with one 60 and one 120 grit?
    Grandpa always told me. "A good woodworker is not one that makes no mistakes. A good woodworker is one who knows how to cover up his mistakes."

  12. #12
    Cal, if you are going to buy new wheels, bite the bullet and get the CBN wheels! You will never regret it.

  13. #13
    Join Date
    Apr 2008
    Location
    North of Boston, MA
    Posts
    282
    If you get the Woodcraft one, ask the dealer to let you test run it before you take it home. Although the wheels that come on it are white, they are notorious for being out of round or out of flat, and it can take quite a bit of fiddling to get the grinder to run smoothly. When I bought mine, we went through three that wobbled terribly before I chose the best one, and it still needed tweaking the orientation of the flanges to take out the shimmies.

    Steve

  14. #14
    Join Date
    Jul 2010
    Location
    Sandia Park, NM
    Posts
    1,068
    I have the Woodcraft low speed with the CBN wheel. Absolutely worth every cent I paid for both items!
    When you approach the lathe you have "the plan", after your first catch you have "the intent".- P. Harbeck

  15. #15
    Well, slow speed is fine, unless you want to do a lot of reshaping your tools. Once you have the profiles that you want, all you need to do is touch things up. There is a huge difference in my 1 hp Baldor grinder, and my 1 hp Woodcraft no name grinder motors, but both work.

    If you are going to buy new grinding wheels for your grinder, CBN wheels (D Way Tools) is the way to go. You may spend more for the wheels, but you will not need the balancing system (not really necessary on most wheels), or dressing/truing/cleaning tools to go with them. They will probably outlast you, and run far smoother than any other wheel you will ever buy. You could get by with just the 180 grit wheel, but I have it and the 80 grit wheel.

    robo hippy

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •