Tip! Mount the Smoothing Broach in a Pin Vise

[VWatchie]

Here’s a tip for those of you who occasionally use a smoothing broach—for example, to smooth out the bearing for the barrel arbor in the barrel bridge. Mount the smoothing broach in a pin vise. It greatly increases efficiency, ease of use, and control. I was genuinely surprised by how much of a difference it made. So much so that I felt I had to share it.

[Neverenoughwatches]

Already there H

[VWatchie]

3 minutes ago, Neverenoughwatches said:

Already there H

 

You should have shared that image with me years ago! 

[HectorLooi]

Haha. You mean you discovered it? Obviously you haven't been doing clocks.

I made handles for some of the smaller ones and glued the broaches in.

[Neverenoughwatches]

A little note to add if I may. This is really handy with larger broaches, if you notice, smoothing broaches have a directional cut to them. The ones I have draw the taper deeper into a hole when turning them anticlockwise. This cut can be quite aggressive, and a hole can grab tight hold of a broach. With the extra leverage from a pinvice it's easier to wind the broach back out.

6 minutes ago, VWatchie said:

You should have shared that image with me years ago! 

Lol, if I tell you all my secrets H you might never talk to me again

[VWatchie]

9 hours ago, Neverenoughwatches said:

The ones I have draw the taper deeper into a hole when turning them anticlockwise.

That is likely the most vital information and tip in this thread. I had a horrible experience with my smoothing broaches before I realized that. Because we are so influenced by how ordinary screws work, we assume that (all?) smoothing broaches are constructed in the same way. So, yes, we need to turn them clockwise if and when they get stuck.

[Neverenoughwatches]

I don't know if all broaches are cut the same way. You can see the shallow spiral under magnification. I was thinking of changing one to a straight up and down the length cut to see what difference it made. 

They're basically a burnisher, like used with a jacot , only round, I wondered why the grain is spiral and not straight ?

That seems to work quite well, the broach happily files away at the hole without getting stuck.

[HectorLooi]

1 hour ago, Neverenoughwatches said:

You can see the shallow spiral under magnification.

Really? Mine are perfectly smooth. It burnishes the insides of the hole until it's shiny.

[Neverenoughwatches]

1 hour ago, HectorLooi said:

Really? Mine are perfectly smooth. It burnishes the insides of the hole until it's shiny.

The german ones I have, have a slow spiral down them, and wind into the hole that they are boaching. Some older ones have straight grooves up them but that might be from sliding them in and out of steel....I doubt that though. So yours are as smooth as needles. ?

[HectorLooi]

1 hour ago, Neverenoughwatches said:

So yours are as smooth as needles. ?

Not shiny smooth as needles. Like sanded with very fine grit sandpaper. Never experienced and binding or drawing in.

Anyway, I have 30+ years experience of reaming root canals. 

Ouch!

[Neverenoughwatches]

5 hours ago, HectorLooi said:

Not shiny smooth as needles. Like sanded with very fine grit sandpaper. Never experienced and binding or drawing in.

Anyway, I have 30+ years experience of reaming root canals. 

Ouch!

I have some like that that , i sanded them up and down yesterday,  they don't bind either.

[mikepilk]

10 hours ago, Neverenoughwatches said:

You can see the shallow spiral under magnification.

I had noticed that they wind in to the hole. Just looked on my Horotec broaches and they are spiral. They have plastic handles, as do all I see on Cousins.

But my cutting broaches don't and I've always used them in a pin vice

What is considered the best broaching technique?  Twisting or in and out, with/without oil ?  () 

 

[HectorLooi]

I recently started using a smoothing broach on mainspring barrel arbor holes as well as the pivot holes of the plates. Then use a small bit of brasso on a pegwood to polish the walls of the holes until they shine. I think it increases the amplitude significantly but don't go crazy until there is excessive sideshake.

[Neverenoughwatches]

12 minutes ago, mikepilk said:

I had noticed that they wind in to the hole. Just looked on my Horotec broaches and they are spiral. They have plastic handles, as do all I see on Cousins.

But my cutting broaches don't and I've always used them in a pin vice

What is considered the best broaching technique?  Twisting or in and out, with/without oil ?  () 

 

I think the cutting broaches take a bit more turning, so pin vices help with that. I'm not entirely sure which twisting direction causes the broach to cut. When I use them I tend turn them anticlockwise and pull against their want to draw into the hole. Turning clockwise pushes the broach back out, i guess either direction works. I found some broaches with straight lines up them and added some more of my own with 400 abrasive cloth. Those have no draw to them. My thoughts are that the broaches also compress and work harden the hole as well.  Oil I would say will give a finer cut and might lessen that drawing effect.

8 minutes ago, HectorLooi said:

I recently started using a smoothing broach on mainspring barrel arbor holes as well as the pivot holes of the plates. Then use a small bit of brasso on a pegwood to polish the walls of the holes until they shine. I think it increases the amplitude significantly but don't go crazy until there is excessive sideshake.

I do that often, but not the polishing part. Or being careful at least not to introduce abrasive into the hole.

[mikepilk]

26 minutes ago, HectorLooi said:

I recently started using a smoothing broach on mainspring barrel arbor holes as well as the pivot holes of the plates. Then use a small bit of brasso on a pegwood to polish the walls of the holes until they shine. I think it increases the amplitude significantly but don't go crazy until there is excessive sideshake.

For the barrel arbor holes I use a pointed felt wheel on the rotary tool with Dialux white or red.

[VWatchie]

On 4/10/2025 at 10:58 AM, mikepilk said:

For the barrel arbor holes I use a pointed felt wheel on the rotary tool with Dialux white or red.

As I don't have a workshop, getting all the tools out's always a bit of a hassle, so I use a toothpick with some Polinum Polishing Compound and do it by hand. The Polinum is highly efficient, so it doesn't take long and is an easy process.

On 4/10/2025 at 10:34 AM, Neverenoughwatches said:

When I use them I tend turn them anticlockwise and pull against their want to draw into the hole. Turning clockwise pushes the broach back out, i guess either direction works.

I think you are right about that, as I do it the opposite way. That is, I turn it clockwise and then resist the broach going out by pushing it back into the hole.

On 4/10/2025 at 10:06 AM, mikepilk said:

Twisting or in and out, with/without oil ?  ()

I have a feeling there's an underlying meaning to what you're saying, but no matter how I try, I can't quite grasp it. Maybe it’ll make sense when I’m a bit older. Anyway, I apply a thin honing oil to the hole. Same oil I use with my Jacot lathe. I think it's important in order to transport away the metal residue from the hole.

Edited April 11 by VWatchie

[Neverenoughwatches]

16 minutes ago, VWatchie said:

have a feeling there's an underlying meaning to what you're saying, but no matter how I try, I can't quite grasp it. Maybe it’ll make sense when I’m a bit older. 

Come on H , you're Swedish for heaven's sake. If you can't  grasp it then nobody can.

[tomh207]

1 hour ago, Neverenoughwatches said:

Come on H , you're Swedish for heaven's sake. If you can't  grasp it then nobody can.

Nothing like a bit of lube to help things along

 

Tom

[mikepilk]

1 hour ago, VWatchie said:

As I don't have a workshop, getting all the tools out's always a bit of a hassle,

Workshop  you would laugh if you could see what I have in my small (10'x9') room.

This is behind me. Yes, that's a dryer (the kitchen is too small) - imagine the dust!
But it's a useful work surface - I put a wood board on top, the rotary drill and abrasives are in the plastic boxes above, and within a minute I'm polishing away.

1 hour ago, Neverenoughwatches said:

If you can't  grasp it then nobody can.

Ooh err missus - would that be with oil 

 

[tomh207]

And you have a ready supply of spring wire!

 

Tom