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Thread: Question on DT and BB gouges

  1. #1

    Question on DT and BB gouges

    Hi

    I'm a new turner, and need some advice. I have a BB 5/8 bowl gouge and a DT 5/8 V gouge. Both have the same grinds. Because of something I'm doing wrong the BB cuts better then the DT.

    I'm using the Wolverine sharpening jig. I have a ~45 degree fingernail profile. I started with the recommended grind on the DT, but changed it to eliminate that as a possible reason for the difference in cuts.

    I'm not flaming the DT and know the DT is a much better gouge, but I can't figure out what I''m doing wrong.

    Thanks in advance for any help.

  2. #2

    Me Too!

    Terry,
    I have the same problem with DT gouges. I have both the 5/8 and 1/2 inch and have ground 1/3 of it away trying to get it to cut as well as my mastercuts or BB gouges.Last week I gave up on them and they lost their spot in my tool rack!
    I have a tormek and a delta vs grinder with wolverine fixtures. I assumed I was doing something wrong also, but I 've run into other turners at my club that have the same issue.
    Tom

  3. #3
    If you guys are talking about Doug Thompson gouges, why not just send them to me, and I will be happy to replace them with brand new BB gouges for you!! Well, probably not for you, Tom, since there is only 2/3 of yours left!

    In all seriousness, I think the difference in the two is that the BB (M2 HSS) will probably take a sharper edge than will the Thompson gouge, but it will lose that sharper edge much, much quicker than will the Thompson. I have had excellent experiences with Doug's tools, and get great cuts with them, as apparently most everyone that has them. I can only surmise that it is something happening on your end. Without being there, and observing the issues, it would be hard to say.

  4. #4
    Join Date
    Jan 2008
    Location
    Loudonville, NY
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    517
    I agree with John.

    I have the same two gouges and I can get what seems like a sharper edge on the BB. I think that part of it is the steel, but the other part is that the actual metal on the sides of the flute on the BB are so much thinner. I tend to only use is for really fine, shearing-type, cuts.

    The Thompson has noticeably more weight to it, can extend further off of the tool rest, and holds its edge much longer than the BB. The powder metal edges do seem to differ from pure M2 steel in all of my tools.

    I have also evolved to maintaining Dougs grid (or close to it) on his gouge, but I use my Ellsworth jig for a sweeping grind on the BB.

    Good luck, and just keep at it.

  5. #5
    Join Date
    Oct 2008
    Location
    Kapolei Hawaii
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    3,236
    I will also agree with John and Chris. I have DTs and Sorbys, and I feel I can get the Sorbys sharper. SO, the DT's are the workhorses, for roughing and the Sorbys are the finishing gouges. I most always reach for the DT first. However, I just recently bought a Oneway 5/8 and been very happy with that. I have a Tormek. The Oneway is sharpened at a different angle, I tried to match the original (very strange) grind.... The Sorby and DT's are all the same grinds.

  6. #6
    Join Date
    Oct 2006
    Location
    Harvey, Michigan
    Posts
    20,801
    Terry - Welcome to the Creek!

    Just my opinion on this as I am not a metallurgist - but there is a difference in steel and you can see that difference when viewing the edge. I agree that the DT will hold an edge longer and, while I have other brands of gouges, the DTs are the only ones I use anymore. One thing you didn't mention is the grit on your sharpening wheel. I changed my slow speed grinder over so that I use a 120 and 150 grit wheels. The 120 takes a little longer if reshaping a grind but most times use the 150 just for a quick touch-up. Finer grit wheel + light pressure and you have one heck of a sharp edge!
    Steve

    “You never know what you got til it's gone!”
    Please don’t let that happen!
    Become a financial Contributor today!

  7. #7
    I'm not sure it's the metal that I have trouble with. I think it's more the geometry of the the gouge. The flute on the Thompson is much shallower than the Oneway or BB.I can get my Thompson gouges very sharp, but they do not cut as quickly or with as much control as my oneway (or BB). Believe me I wanted them to work and the reason I've ground off a third is that I thought I must be doing something wrong and kept trying different angles and sweeps. I have the utmost respect for Creekers and rely on this forum for tool review. I believe that all the positive Thompson reviews are sincere and accurate, I just can't get them to cut!
    John, I would be happy to send you some photos of my gouges to see if there is enough steel left to make it worth your while (and postage)
    Thanks Tom

    Doug,
    I ABSOLUTELY love the two Thompson detail gouges I have, and my next skew will be coming from you.

  8. #8
    Join Date
    Oct 2006
    Location
    Harvey, Michigan
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    20,801
    Tom - any chance you can post a closeup photo or two of your grind? Might be able to figure out what is going on...
    Steve

    “You never know what you got til it's gone!”
    Please don’t let that happen!
    Become a financial Contributor today!

  9. #9
    My guess is it is more of a geometry issue than a metalurgical one. The grain structure of the cryogenic abrasion resistant metal is at least as fine as the M2? in a BB gouge, and should take at least as keen an edge and hold the fresh edge longer.

    My first bowl gouge was a homemade one from O1 and had a U-shaped flute. That is the shape flute I learned to turn with. I did get tired of it not staying sharp, so bought a BB gouge. I hated that gouge from day one. The flute has a deep V shape with a small radius in the bottom. I could not get used to the flute shape, especially on the inside of a bowl, and went back to the homemade U-flute until I had a chance to buy a U-flute gouge from Doug. I will add that even though Doug has V-flute gouges, they do not have as tight a radius in the bottom as the BB gouge I have. As the radius at the bottom of the flute changes, so does the tool presentation. A larger radius requires closing the flute (pointing the flute away from the wood) more when working inside a bowl. Also, when making the initial presentation to the rim of the bowl, the flute needs to be closed moreso than with a V-flute. The smaller radius in the bottom of a V-flute allows for a more forgiving flute presentation when starting the cut. A open flute presentation with a U-flute will skate.

    From looking at Sorby gouges, they have also have what I consider a 'tight' radius in the bottom of the flute, and like the BB gouge, I prefer not to use them for that reason. Each flute geometry has its own techinque.

    From my way of thinking working the inside of bowls;

    Larger radius = smoother cuts and more critical presentation.
    Smaller radius = Less smooth cuts, and more forgiving presentation.

    I can have spectacular catches with any flute shape however .

  10. #10
    Dale - excellent input!! Having only used a Thompson V gouge, I had never considered this. I do have a couple of smaller P&N gouges that I use for detail work, etc., and they do have a different feel to them.

  11. #11
    Join Date
    Sep 2008
    Location
    Chandler, AZ
    Posts
    456
    I have been using Dougs V shaped bowl gouges for a couple weeks now and can attest to the different feel / presentation to the wood from the U shaped BB tool. It took a little retraining to my brain but I think I found the sweet spot now. I expect that Dougs U shaped gouge will be much more similar to the U BB that I had before. Also, I believe Doug receommends the V shape for more wet turning than dry blanks... but for me I usually turn dry and bought the V shape anyway.
    -----------------------------------------
    Actually lifted this from Dougs FAQ on his site:
    V Shape or U Shape that is the question!
    If you ask 100 people the same question you’ll get 101 different answers. I prefer a V shape because the V shape flute can be very aggressive when roughing especially on green wood. When you need to remove a lot of stock when roughing a bowl or turning a hat where 99% of the blank ends up as shavings the V shape is the only way to go. The small nose radius is not grabby when entering a cut and can be used to create details. Because the wings tend to be longer on a V shape tool scraping is easily done on the outside of a bowl. In the past a V shape flute was known to clog with shavings, the design of this flute was changed so it doesn’t happen.

    The U shape flute has some strong points especially when turning dry wood. The large nose radius allows the tool to shear the wood which is good to prevent tear out, the finish cut inside a bowl or long sweeping curves outside a turning are just two examples where this tool excels.
    -----------------------------------------

    Good luck - hope you find the sweet spot.
    Jon

  12. #12
    Thanks for the comments.

    Tom: Glad I'm not alone!

    Steve: Thanks. I'm using a 120 wheel. I'll also post some picts later today.

    Jon: I'll keep looking for the sweet spot.

    I really like the overall feel of the DT, and know I'll love it after I get over this hurdle.

  13. #13
    Join Date
    Jan 2005
    Location
    Goodland, Kansas
    Posts
    22,605
    You have gotten some good advice and I do agree with Jon. I use my Thompson V gouges for hog off wood, the U shaped for finer cuts and the P & N conventional for the finihsing cuts on most bowls.
    Bernie

    Never put off until tomorrow what you can do the day after tomorrow.

    To succeed in life, you need three things: a wishbone, a backbone and a funnybone.



  14. #14
    Join Date
    May 2006
    Location
    N. Olmsted, Ohio
    Posts
    355
    Terry,
    Do take a picture so I can see what the problem is. The grind right out of the package is a standard grind that does most everything well... when it's changed the cutting angles could be lost. The basic grind is what John Jordan, Bill Grumbine and Jimmy Clewes use on these tools and they have no problem with sharpness, cutting angles or lack of control. Keep it simple.

  15. #15
    For us novices out here, could someone tell me what a "BB" is? I read all the posts hoping to figure it out.

    I got that "DT" is Doug Thompson and have a full selection of them.

    I use the Grumbine for heavy roughing as others mentioned. I'm saving up to buy another and grind it with a steeper angle for really deep cuts.
    I bought the 1/2 "v" and "u" and the 3/8 (I think) 'Jimmy Clewes", all of which I like. I've been using the Jimmy Clewes as a sort of detail gouge. One of my favorite guoges, though, is a 3/8 Glaser made of powdered metal. Like others mentioned, it just seems to be sharper than any other tool I have.
    TB

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