What is this Called

[Phil super7Participant @philsuper7]

I Found This Amongst Some Used Taps & Reamers I Bought.

It is 5 Sided.

Does not have cutting Edges like a Reamer and is Tapered.

My question is What is called, and what is it used for.

[John HaineParticipant @johnhaine32865]

It’s a rather large cutting broach, used to enlarge holes typically in brass clock plates.  Available from clock sundies suppliers.

https://www.cousinsuk.com/product/individuals-0375-to-01049mm

Still useful tools though not exactly precision.  Best for cutting brass, would be hard work in steel.

[Speedy Builder5Participant @speedybuilder5]

looks to be about the right taper for easing holes for taper pins ??

 

[DiogenesParticipant @diogenes]

Taper-pin reamers usually have the same ‘flute & land’ structure as a standard parallel reamer..

I’m sure John’s bang-on.

[JasonBModerator @jasonb]

Yes a cutting broach. I have a few and they are quite useful at times.

[Martin KyteParticipant @martinkyte99762]

Clock making Broach for sizing pivot holes. The slight taper allows for a small amount of movement away from the perpendicular which avoids binding if the holes in the clock pates are not exactly opposite each other so the fit can be made closer. It also means that the bearing contact area is a small annulus which reduces friction. Similar smoothing broaches exist of the same shape but without the facets. They go down to very small sizes too.

[Phil super7Participant @philsuper7]

Thank you all for your quick replies, another school day for me.

[Author]

Posts