Delapena External Hones

Hi,

I recently acquired a pair of Delapena external hones, one small and one large. Some of the stones are in poor shape and I would like to sort them out.

I understand that these tools are no longer made so I am looking for replacement abrasive stones assuming I can remove the existing stones from the holders and glue in replacements.

The stones are numbered 11 to 15-P8-F for the bigger tool and 3 to 6-P8-F for the smaller one. Looking at the Delapena Web site I think F denotes silicon carbide but I can't see anything to decode grit size.

The hones will be used on decent steels, En16, EN24 and case hardened EN36B for example.

The bigger stones are 2" long 3/16" wide and 1/8" thick, the smaller ones are 3/4" long by 0.1" Square.

The existing holders could be modified to suit stones of a different section assuming I can cut the replacement stones to length somehow.

I have emailed Delapena to see if they have any info or suitable stones, but I thought I would ask the forum at the same time as someone is bound to have done this already or will have some good ideas.

Thanks,

Ian

Have a look on Ali*****ss probably thousands of choices grits up to 3200# for these type of stones can't give any reference numbers on here as they will be taken down almost instantly.

John

Try these

https://www.kemet.co.uk/products/toolroom/gesswein-abrasive-stones

I use them not cheap but ask them and they will suggest the corect style and grade etc

David

Hi IanH,

If I can recall all this correctly...but please bear in mind that I am trying to remember detail from decades ago, when I was still in the Toolroom. Grit Sizes on the smaller stones/hones were available from 60 to 500grit and the Delapena Codes for these smaller stones was split/defined as follows:

Delapena code 0 = 60 grit, 1 = 80 grit, 2 = 120 grit, 3 = 180 grit, 4 =220 grit, 6 = 320 grit & 8 = 500 grit

You are correct in that F = Silicon Carbide...

The other common abrasives, readily available were: R = Aluminium Oxide (Soft Steels up to HRC 50), C = Bauxilite, which was cool cutting and for Hardened Steels over HRC 50)...I also seem to recall that they used to supply another couple of variants of "speciality stones", for special finishes...but I can't recall what they were...

Thinking back...I think? the other letter in the Code relates to the Bond Hardness. Hard Materials needed a Soft Grade...and Vice-Versa...

Sorry that I can't give you more information...but I am sure that someone out there must have some old "bumf" lying around...Hopefully they will step in...and clarify any holes...

Best Regards,

Adrian

Ian please see your messages,

The original method of fixing the stones to the carriers was a powder adhesive you applied to the mount then heated it on a hot plate [i use an old flat iron upturned] the worn stones can be removed with heat. I guess now its possible to use an epoxy,

John