My gouges won’t sharpen

[cultana]

My gouges won’t sharpen. Not a huge issue just annoying.

OK they were my first set of tools I bought, the type that comes in a nice wooden box with no name, yes Chinese ones.

So far I have chewed away about 3/4 of my bowl gouge and about 1/2 my spindle gouge with turning work. Now it is impossible to get an edge on these.

When these are ground pieces if the cutting edge flakes off with a brittle fracture.

I can understand that I would chew these up because they don’t hold an edge for as long as the more expensive brands but this just seems to be a bit of an oddity.

But all that aside this should not happen, should it?:?

[Grumpy John]

Did you overheat them i.e. they turned blue and then you quenched them in cold water. I hope not.

[Chief Tiff]

Sounds like the heat treatment applied to the steel wasn't constant along the tool, whether this was deliberate or not I have no idea.

To say that you've got through 3/4 of your bowl gouge though tells me that maybe it's time to go shopping anyway! I've been buying Sorby tools directly from the UK via a mob called Turners Retreat (http://www.turners-retreat.co.uk/). Good service and excellent postage rates coupled with the strong dollar means you save quite a bit.

I would be interested in knowing the type of tool set you bought; I purchased this (http://gpwoodturning.sitesuitestores.com/cgi/index.cgi/shopfront/view_product_details?category_id=1107146793&product_id=1107445171) set from GPW and was wondering if I might have a similar problem later on. The steel is good and holds it's edge well....so far!

[cultana]

Sounds like the heat treatment applied to the steel wasn't constant along the tool, whether this was deliberate or not I have no idea.

My understanding of heat treatment suggest the same idea. Possibly part was done correctly and that closer to the handle was not done properly or left out completely.

I would be interested in knowing the type of tool set you bought; I purchased this (http://gpwoodturning.sitesuitestores.com/cgi/index.cgi/shopfront/view_product_details?category_id=1107146793&product_id=1107445171) set from GPW and was wondering if I might have a similar problem later on. The steel is good and holds it's edge well....so far!

No, I have some of Gary's stuff and no probs. His tools even come out of the box sharp. Besides if they were from him I would have raised the matter direct and not here on this forum.

These gouges come from a different source.

[cultana]

Did you overheat them i.e. they turned blue and then you quenched them in cold water. I hope not.

I know all about that issue. Though I have seen some very experienced turners water quench when they turn blue. :doh:

[Frank&Earnest]

I have questions more than answers, but I can report that I have one set like that (did not need it but it was on sale for $48! :D ) and in my limited knowledge they seemed to perform as well or better than gouges I paid $60 each. I say "seemed" because now I don't need to sharpen steel tools very often :;:D

My understanding was that blueing does not matter for HSS, though. And I used to quench carbon steel before it went blue. That's what everybody was doing in the old days.

[hughie]

My understanding was that blueing does not matter for HSS, though. And I used to quench carbon steel before it went blue. That's what everybody was doing in the old days.


HSS or M2 as what most of the tools are made from and M2 has good red-hardness and retains its cutting edge longer than other general purpose high speed steels. The bluing is not an issue as M2 is designed to perform at higher temps.

ICS Cutting Tools - high speed tool data (http://www.icscuttingtools.com/Tooldata.htm)
M2 Data Sheet - M2 High Speed Steel technical data sheet (http://buffaloprecision.com/data_sheets/dsm2hs.htm)

and see S600 Bohler M2

Bohler-Uddeholm Australia - High Speed Steel (http://buau.com.au/english/b_2265.htm)

There are concerns with cooling hot tools in water, thermal shock is often sited as the reason. But I have seen over the years HSS tool bits ground and cooled in water as a matter of course. Some are for and some are against, I suspect it has some effect but have not run into any research data on the matter.

[cultana]

I have questions more than answers, but I can report that I have one set like that (did not need it but it was on sale for $48! :D ) and in my limited knowledge they seemed to perform as well or better than gouges I paid $60 each.


At present not having either a bowl or spindle gouge is not a big issue. They have been replaced by two Oland style tools and these seems cover what I want.



I say "seemed" because now I don't need to sharpen steel tools very often :;:D

I presumed so.:D
CT inserts may be the next phase for me.

[cultana]

HSS or M2 as what most of the tools are made from and M2 has good red-hardness and retains its cutting edge longer than other general purpose high speed steels. The bluing is not an issue as M2 is designed to perform at higher temps.

ICS Cutting Tools - high speed tool data (http://www.icscuttingtools.com/Tooldata.htm)
M2 Data Sheet - M2 High Speed Steel technical data sheet (http://buffaloprecision.com/data_sheets/dsm2hs.htm)

and see S600 Bohler M2

Bohler-Uddeholm Australia - High Speed Steel (http://buau.com.au/english/b_2265.htm)

There are concerns with cooling hot tools in water, thermal shock is often sited as the reason. But I have seen over the years HSS tool bits ground and cooled in water as a matter of course. Some are for and some are against, I suspect it has some effect but have not run into any research data on the matter.

I think that the issue with some of the less expensive:D chisels/gouges , (unbranded types), is that they may not be M2 grade but more of the general HSS. Also some of the processing carried out may not be the best practice.



I did heat up the two gouges but only to a dull red then air cooled them. The spindle gouge now does take a sort of cutting edge with no change on the bowl gouge, it is totally Rat droppings.

[Rifleman1776]

What are you using to sharpen? What grit wheel? Too coarse a wheel will eat down anything.
El Cheapo Chinese tools can work very satisfactorily. Not as good as some (not all) of the high priced varities but still, for the price, can be good.
Personally, I like a 120 grit wheel at 1750 rpm.

[Paul39]

Cultana,

If your tools are not marked High Speed Steel they are most likely carbon steel.

The bowl gouge may have been improperly hardened or not tempered correctly, so that it is brittle.

Here is more than you probably want to know about heat treating carbon steel by a knife maker.

http://www.dfoggknives.com/hardening.htm

You can search on Google and find several home made ways to harden and temper carbon steel.

I use a collection of bought high speed steel, carbon steel, and mystery steel tools. Also HSS planer blades (12 X 2 1/2 X 3/8 inch thick), ground files, screw drivers, junk shop knives, shafts from computer printers, and steel picked out of junk piles. Bread knives with the sharp edge ground off make wonderful thin cut off tools, 50 cents each at junk shops around here.

All work, the HSS tools the longest between sharpenings. My favorite hollowing tool is a piece of 1/2 inch square steel that was used as a concrete form stake. I have ground the end to look like a 1930s streamlined locomotive.

Like this without the cow catcher or headlight:

Google Image Result for http://cruiselinehistory.com/wp-content/uploads/2008/05/stream2.jpg (http://www.google.com/imgres?imgurl=http://cruiselinehistory.com/wp-content/uploads/2008/05/stream2.jpg&imgrefurl=http://cruiselinehistory.com/%3Fp%3D233&usg=__vPF_zqPdnBHLcEp7IyC6uNGDrAc=&h=720&w=1200&sz=115&hl=en&start=0&zoom=1&tbnid=Diw2ei7Xl72APM:&tbnh=129&tbnw=215&prev=/images%3Fq%3D1930s%2Bstreamlined%2Bdiesel%2Btrain%26hl%3Den%26sa%3DG%26biw%3D1126%26bih%3D624%26gbv%3D2%26tbs%3Disch:1&itbs=1&iact=hc&vpx=585&vpy=96&dur=1647&hovh=174&hovw=290&tx=101&ty=100&ei=va3MTMPGHIT68AbpxqGYAQ&oei=va3MTMPGHIT68AbpxqGYAQ&esq=1&page=1&ndsp=12&ved=1t:429,r:2,s:0)

I use it as the train would be upside down. I guess you could call it a round nosed Bedan. When I turn I have the grinder (1725 rmp, 8 inch 80 & 120 grit white wheels) running all the time. It is right at the tail end of the lathe.

I sharpen the selection of tools, turn until the tool is not cutting freely, give it a swipe on the 120, turn, swipe, etc., etc.

With dry oak, locust, or walnut, it sometimes is as little as 30 seconds of cutting before sharpening. The HSS tools last 3 to 4 times as long.

I really like a freshly sharpened and honed carbon steel scraper for taking the last whisker off of the inside and outside of a bowl.

[Ed Reiss]

A long time ago in a galaxy far, far away....well it seemed like it anyway!!!:q

Jerry Glaser set me straight on sharpening HSS. You can get them blue, but don't quench in water because micro-fractures will develop.

Also the first portion of gouges are tempered for use...go beyond that point and your dealing with slop steel.

[cultana]

Jerry Glaser set me straight on sharpening HSS. You can get them blue, but don't quench in water because micro-fractures will develop.

Sounds like something from my dim dark days in a metallurgy lecture...

Also the first portion of gouges are tempered for use...go beyond that point and your dealing with slop steel.

Ed: I think that is the problem but slop steel may be a nice way to call it.:D

[cultana]

What are you using to sharpen? What grit wheel? Too coarse a wheel will eat down anything.
El Cheapo Chinese tools can work very satisfactorily. Not as good as some (not all) of the high priced varities but still, for the price, can be good.
Personally, I like a 120 grit wheel at 1750 rpm.

Same stone I have always used, 120 grit, white AO and running about 2000 RPM. The eating away is just because I use hard timber and the tools need sharpening a lot.

[Ed Reiss]

Ed: I think that is the problem but slop steel may be a nice way to call it.:D

hmmmm...untreated section might have been more descriptive.