Which Countersink Bit?

[NarrowGauge]

Can I please ask for your preferences regarding countersink bits.

I have tried traditional rose, and 'engineers' multi flute bits, but have had problems either with chatter or unsightly irregular forms.

My main materials are brass and mild steel, up to 1/4" diameter, but with emphasis on 2 BA or smaller sizes.

I have seen hollow, or snail bits advertised and wondered if they were to be recommended.

Is any type of lubricant advisable?


Thanks

Dave.

[Allan Waterfall]

Always a good idea to clamp the workpiece rigidly.
I always use a slow speed and keep the pressure on.

Allan

[lancelot]

I have tried traditional rose, and 'engineers' multi flute bits, but have had problems either with chatter or unsightly irregular forms.
Hello Dave, In my opinion these are not metal c/ks but mainly used for wood.
The SNAIL is mainly used as a deburring tool,althrough in saying that ,a good sharp one,can cut a quite deep c/k when you may not want it to.
In the Aircraft Industry,metal working c/ks nearly always had a spigot type lead,depending on hole size,
this was to prevent the c/k from chattering or wandering off centre.
If you happen to have any friends in Aircraft maintenance,beg borrow or purloin,a little tool called a Microset. This tool has the advantage of interchangeable cutters,with interchangeable leads.Cutters can have different cutting angles to suit screw pattern.
The greatest advantage of this tool is its capability to be set like a micrometer to a preset depth,thus giving very accurate c/ks.
I hope this information is of some help to you,
All the best for now ,
john.

[Peter W.]

A "Huffam" countersink gives good results.
It has two flutes, and is used at slow speed,
with cutting fluid.

Mind you, it was expensive, but I was getting
desperate too !
Can't remember at the moment where I bought it,
but will chase it up if you have any difficulty.

All the best,
Peter

[NarrowGauge]

Thanks all for the comments and suggestions.

The idea of keeping a firm feed I can understand. The problems arise when you know, in the smaller sizes, that you only want to make a shallow countersink. You then become worried about a deep pocket being produced, if the bit snatches etc.

John, the Microset tool sounds interesting. Is there a chance of any more information, as I am not connected with the aviation maintenance industry. Might it be available commercially under another name?, as a quick google revealed nothing.

A Huffum google also draws blanks Peter. If you had any further details or information, it would be appreciated.

Thanks

Dave.

[Allan Waterfall]

I usually do them in the mill if I want a consistent depth and use the fine feed for feeding in.

Allan

[lancelot]

Hello Dave,
no wonder you could not find ''microset''c/k,although we always called them by that name,the proper name would appear to be ''microstop''c/k.
A quick check on Google threw up quite a list.try this one.
aircraft spruce.com

www.aircraft spruce.com/catalog/toppages/microstop.php

Like yourself,I Googled for the other c/k ''huffam''?but did not find any thing,
All the best for now,
John

[Peter W.]

I've checked the 'records' ;D and see that I bought the
Huffam c/k from Millhill supplies (millhillsupplies.co.uk)

Mine is 3/8" x 90, 1/4" shank, but they have smaller ones (down to 1/8).
Like Allan, I use the mill/drill fine feed for consistent results, and check with a screw as well if being finnicky !

The manufacturers have a web site :- huffam.com

All the best,
Peter

[NarrowGauge]

Thanks John and Peter for the further details, I will be following up the contacts.

Your suggestion Allan of using the fine feed/stop on the mill is a good one and I shall certainly be using that method in the future.

Thanks to all

Dave.