Delapena External Hones

[IanHParticipant @ianh]

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

[IanHParticipant @ianh]

Stone replacement

[John PParticipant @johnp77052]

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

[David George 1Participant @davidgeorge1]

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

[Adrian NicolsonParticipant @adriannicolson]

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

[JohnFParticipant @johnf59703]

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

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