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Burned bowl gouges

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Forum topic by BenDupre posted 09-02-2017 01:06 AM 544 views 0 times favorited 16 replies Add to Favorites Watch
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BenDupre

513 posts in 269 days


09-02-2017 01:06 AM

I have a 8 in slow speed grinder made by WEN. It has the white wheels. I do not know what material they are. I am using a jig to sharpen my bowl gouges but i cannot even make one pass on the fine wheel without burning the wings. I dip in water between passes bit it’s too late. Any turners have a suggestion on how to grind a bowl gouge without burning? THANKS!

-- The problem with communication is the illusion that it has occurred. – George Bernard Shaw


16 replies so far

View Jerry's profile

Jerry

2345 posts in 1429 days


#1 posted 09-02-2017 01:15 AM

It’s difficult to get this right, but use the slow speed, very little pressure, and wet the gouge before you ever put it on the wheel for the first time, wet it after each pass on the wheel. If that doesn’t work, it sounds like you’ve already lost your hardness. You could try re-hardening the steel with a propane torch to heat it up and a PVC pipe oil quench tank.

Woodworker's Guide to Heat Treating Tool Steel

-- There are good ships and there are wood ships, the ships that sail the sea, but the best ships are friendships and may they always be. http://www.geraldlhunsucker.com/

View Nubsnstubs's profile

Nubsnstubs

1180 posts in 1511 days


#2 posted 09-02-2017 02:13 AM

if your tools are HHS, don’t quench them. That will supposedly ruin them. A little blue on HHS isn’t suppose to be all bad, but a lot of blue could damage them…......... .... ............. Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

View Jim Jakosh's profile

Jim Jakosh

19290 posts in 2886 days


#3 posted 09-02-2017 02:37 AM

I’m wondering what grit wheel you have? I have a high speed grinder and use a 100 grit wheel. I do get some discoloration on the edges some time but I do not grind hard. I float the gouge over the wheel while in the jig and dip it in water after each pass. They stay fine, even if discolored a little.

Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

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Wildwood

2149 posts in 1915 days


#4 posted 09-02-2017 10:43 AM

Guess your 1750 RPM grinder comes with 60 & 120 grit wheels you would have to remove wheels from the grinder and read the labels if not listed in owners manual to find out which is which.

You are pressing too hard if bluing any part of your tool. Resharpening only about touching up the edge of tool and only takes seconds to to that. All you need is a light touch at the grinder.

Like already said don’t want to blue HSS steel and tool should not get hot to the touch if just touching up the edge of the tool. Quenching not a good idea too! If see lot of metal in your wheels time to clean the wheel with a wheel dressor.

A good primer on grinding wheels:
http://www.georgiagrindingwheel.com/grindingwheels_basics.htm#faq1

I use 80 grit & 46 grit wheels on my grinder after years of sharpening these wheels work for me.

http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=packard&Category_Code=sharp-n3xw

-- Bill

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Markmh1

55 posts in 224 days


#5 posted 09-02-2017 01:17 PM

The first thing I would guess is the wheel needs dressing. On a surface grinder this is done with a diamond. I don’t know how you would hold a diamond and guide it across the wheel on your Wen. Some kind of fixture?

The second guess is the wheel is too fine a grit. I’ve gotten remarkable finishes with a 46 grit wheel. Keep in mind hogging material is not conducive to a fine finish.

Mark

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Wildwood

2149 posts in 1915 days


#6 posted 09-02-2017 07:06 PM

There are several types of wheel dressers out there and can pay little or a lot. Not sure if your Home Depot has this style in stock but they can get you one for not much money.

http://www.homedepot.com/s/grinding%2520wheel%2520dressor?NCNI-5

Been using this style for several years, drilled a hole in a block of wood, and slide it along Wolverine platform to dress my wheel. Shipping lot cheaper back then.

http://www.grizzly.com/products/Diamond-Dresser-1-4-Carat/H5891?utm_campaign=zPage&utm_source=grizzly.com

Shop around for best price.

-- Bill

View BenDupre's profile

BenDupre

513 posts in 269 days


#7 posted 09-03-2017 05:25 AM

I will try dressing the wheel. I am not putting any pressure just swinging the tool through the arc as quickly as i can manage it. The wings are quite thin.

I might try a different wheel. I dont think I can afford CBN. What is the next best affordable choice?

-- The problem with communication is the illusion that it has occurred. – George Bernard Shaw

View LeeMills's profile

LeeMills

438 posts in 1082 days


#8 posted 09-03-2017 01:24 PM

I haven’t seen anyone else ask but… what brand tools are you using?
Can you post a picture? You state that “The wings are quite thin” so they will probably burn quicker.
You should not have the problem with HSS but older tools, or very inexpensive, may cause it.

-- We cannot solve our problems with the same thinking we used when we created them. Albert Einstein

View Wildwood's profile

Wildwood

2149 posts in 1915 days


#9 posted 09-03-2017 02:18 PM

General rule of thumb for AL friable wheels( blue, pink/red, or white): Use a course grit for rapid stock removal and finer grits for less stock removal but better surface finish. If can acept 36 -60 grit a medium, 80 – 120 grit as fine, and anything over 150 grit as super fine.

You have to understand things can and do vary from one manufacturer to another. Bonding material, grit, hardness, and structure or grain has lot to do with wheel performance. Finding the wheel combination for reshaping or repairing damaged bevels & resharpening a daunghting task. Not many turners agree on what is the best wheel to buy.

So we all have to find our own way in sharpening our turning tools.

These are the wheels that meet my needs and where buy them.

http://www.packardwoodworks.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=packard&Category_Code=sharp-n3xw

Nice article from a semi production turner.

http://c.ymcdn.com/sites/www.woodturner.org/resource/resmgr/fundamentals/grinding_wheels.pdf

-- Bill

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BenDupre

513 posts in 269 days


#10 posted 09-03-2017 05:19 PM

Tools are benjamins from PSI and Hurricane from IDK where. Both are advertized to be HSS. I have a Sorby gouge but right now I am afraid to put it on the wheel. I will post some pics later today.

-- The problem with communication is the illusion that it has occurred. – George Bernard Shaw

View JoeinGa's profile

JoeinGa

7709 posts in 1788 days


#11 posted 09-03-2017 05:31 PM

I have been using this type wheel dressing tool for about 25 years. I think I’ve only replaced the wheels ONCE in all that time. Have no idea what they cost, I found this one at a garage sale and if I remember right I paid the guy one dollar because he didn’t know what it was for.

-- Perform A Random Act Of Kindness Today ... Pay It Forward

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BenDupre

513 posts in 269 days


#12 posted 09-03-2017 05:34 PM



I have been using this type wheel dressing tool for about 25 years. I think I ve only replaced the wheels ONCE in all that time. Have no idea what they cost, I found this one at a garage sale and if I remember right I paid the guy one dollar because he didn t know what it was for.

- JoeinGa

I have one like that but i was going to try a diamond dresser because i think my wheel is getting dished

-- The problem with communication is the illusion that it has occurred. – George Bernard Shaw

View EricTwice's profile

EricTwice

223 posts in 314 days


#13 posted 09-03-2017 05:37 PM

I only use course grit to grind my tools and then hone the wire edge off (sharp as a razor)

and I agree with the above, the wheels work much better if they are cleaned and dressed with one of these


-- nice recovery, They should pay extra for that mistake, Eric E.

View papadan's profile

papadan

3584 posts in 3149 days


#14 posted 09-03-2017 05:44 PM

Ben, try and sharpen one of the tools with a fine file. If it works, your tools have lost their hardening and need to be rehardened. Sometimes on tools they only harden the last 1/2” of the blade. Once you get them sharp, keep them sharp with a hone instead of going back to the grinder.

View LeeMills's profile

LeeMills

438 posts in 1082 days


#15 posted 09-03-2017 09:07 PM

I have not heard of this problem with the PSI tool. I do have several Hurricane and have not had a problem with any of them bluing.
For the white stones you may like this type which allows me more control to get the stone completely flat and remove as little as possible. I do not know which brand I have but have been using it 5 or 6 years.
I think the Uxcell is a decent brand but others may be better.
https://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=diamond+wheel+dresser

-- We cannot solve our problems with the same thinking we used when we created them. Albert Einstein

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