never seen anything like it

[Speedy Builder5Participant @speedybuilder5]

Just picked up some new French metric (I guess the same as UK metric – just French made !) reamers from a car boot sale. I have never seen reamers like it, but was assured that they will cut accurate holes in steel, brass etc.

 

A third of the circumference have no cutting flutes, and the other two thirds have normal flutes. Anyone used / seen these before ?

[Speedy Builder5Participant @speedybuilder5]

Reamer

[Speedy Builder5Participant @speedybuilder5]

344 other people never seen anything like it – surely some one knows.

[Anonymous]

Since there are no pictures, technically you’re the only person who has seen it!

 

Regards,

 

Andrew

[Roderick JenkinsParticipant @roderickjenkins93242]

Robert,

 

Taper reamers for making the holes for musical instrument pegs have only 3 flutes on half the circumference, the rest being plain. If you try to cut a hole in a soft material like wood using a conventional reamer the reamer tends to pivot around the cutting edges in turn and you end up with a facetted hole. I guess a similar thing can happen in soft metals, it certainly can happen in sheet material. I would expect your reamers to be very accurate, if a little slow cutting. Spiral flute reamers are now available for musical instrument which helps to eliminate the problem but they still have a least one flute missing (or at least that’s how it is on my lute peg reamer).

 

Rod

[dcostaParticipant @dcosta]

Hello Robert!

When I started my intereste in engineering, in the beginning of the eighties, I saw reamers like that many times in professional shops. At that time I heard they being called something like “backed reamer”. In its name (that in portuguese is descriptive of the reamer, not just a name), the third of the circumference without cutting flutes is the “backed” part of the reamer. I think they were of common use here in Portugal.

I’ve used one or two and, yes, they work very well.

Only now I thought about how that reamer work. I think that the function of the “backed” part is to crush small bosses left by the normal flutes and also to (kind of) polish the surface.

I only recently re-started my interest in engineering and in the meatime I think I lost them. Tried to find them with no luck.

Best regards

Dias Costa

[Chris TriceParticipant @christrice43267]

Bit of a cross between a reamer and a D-Bit maybe.

[NobbyParticipant @nobby]

Hi

If the reamed hole is a bit small .On the 1/3 plain section you can add say .001 shim etc.& ream by hand.Having said that I havent seen them

Nobby

[JohnFParticipant @johnf59703]

Hi Robert,

Yes I have used this type of reamer some 40 years ago in industry, they often came with carbide inserts in the plain portion to prevent wear–always with a carbide cutting tip as well. They are a little slow cutting and you really need to flood with coolant or oil and run relatively slow.

They cut a very straight hole and yes they operate similar to a D bit but cut faster and more efficiently. If memory is good they were designed by PERA [production engineers research organization] They never caught on with the major tool makers and I have seen few since–still have a couple somewhere I think!

Regards John

[Author]

Posts