By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Jan 24th

Form Tool Sharpening

All Topics | Latest Posts

Search for:  in Thread Title in  
Buffer09/05/2019 22:22:06
147 forum posts
42 photos


I have just used a bench grinder and ground my first form tool in HSS for making some brass bits. The cutting edge is about half an inch in length.

Can anyone tell me what is the best way of smoothing out the edge and sharpening this? As its a curve its not obvious.





Howard Lewis09/05/2019 22:25:24
3154 forum posts
2 photos

A round fine stone, or a round diamond hone?


Hopper09/05/2019 23:46:22
4421 forum posts
94 photos


ronan walsh09/05/2019 23:46:43
541 forum posts
32 photos

Howard has it, i always smooth out cutting edges on ground tools with a stone.

Buffer10/05/2019 08:33:48
147 forum posts
42 photos

Ok thanks. The dremel wheels I have had in the past have always just worn themselves away more than the metal!

I will look for a rounded stone

Thanks for the advice


Baz10/05/2019 08:57:33
360 forum posts

Bit of brass or Ali held in pillar drill chuck and run slowly with a finger full of valve grinding paste and then present the tool at a slight angle. In a couple of minutes you will have a narrow band finely ground, a quick stone on the top and the jobs done.

Mick B110/05/2019 11:31:09
1554 forum posts
83 photos

Once you're happy with the shape, finish and clearance angle of the curve, grind the top face to produce the edge. If you put a few degrees of side rake on it, it'll work well enough for most other common materials as well as brass.

Andrew Johnston10/05/2019 11:42:39
5422 forum posts
629 photos

For free form shapes I hand grind, possibly against a template, and finish with diamond hones. If the profile is important I'll machine it and finish with diamond hones.


Ian S C10/05/2019 12:25:56
7468 forum posts
230 photos

For a similar shape to your's Rich I grind out the bulk of the metal on the bench grinder (now I would start with the angle grinder), then get the shape near right with the Dremel, and use a slip stone to sharpen (as used to sharper wood gouges).

Ian S C

Buffer10/05/2019 15:23:23
147 forum posts
42 photos

Thanks for the advice, lots of techniques here.

I like the idea of grinding paste on a spinning bar might give that a go first.

Ian what bits do you use in the dremel? The little grinding wheels that came with it just wear themselves away.



Derek Lane10/05/2019 19:31:23
318 forum posts
73 photos

For sharpening my HSS turning tools I use a diamond card with a little window cleaner as a lubricant, so I would go with a round diamond file and do the same Once you have it very close to shape

Jon10/05/2019 20:48:45
997 forum posts
49 photos

Its a pain but got to be done, grind the relief if your very good can double it up for cutting edge.

Ian S C11/05/2019 12:58:24
7468 forum posts
230 photos

Rich, in the Dremel I use a stone just smaller radius than the the shape to be ground out, get as near a you can on the bench grinder first, Baz's method would then be good to finish the tool.

Ian S C

Nick Hulme12/05/2019 17:29:22
743 forum posts
37 photos

You should grind your form tools such that they have the angles required, and not "Sharpen" them afterwards.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Eccentric July 5 2018
Allendale Electronics
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest