Arbor press vs. hammer


July 14, 2014, 05:08 AM
Just curious: Why aren't small rack-and-pinion type arbor presses used to push out/install pins found in guns, instead of using hammers? Or perhaps they are? I'm talking about the mechanical, bench top models where one can "feel" the pressure being exerted.

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July 14, 2014, 07:16 AM
Probably because most do not own such arbor presses and a hammer quickly, easily and reliably does the job unless the person wielding it is a complete maladroit.

O'course, a maladroit would also probably screw up the job using an arbor press. ;)

July 14, 2014, 08:39 AM
Some shops do. It all depends on what there working on. A press works much better than a hammer on very very tight pins. Sig FP Retainer pin comes to mind. If done right there will be no indication it was removed.

July 14, 2014, 09:37 AM
I don't usually use my arbor press for small pins but it is handy to have for many uses. I removed the bayonet bracket from one of my M44 Mosins with it. I don't use it often, but it doesn't take up much bench space, an it's ready when I am.


July 14, 2014, 10:01 AM
I can think of two reasons, more people own hammers than arbor presses and fixtures to properly hold any shape one might want to push a pin from.

Pushing a pin punch by hand or a tap with a hammer is a lot faster.

July 15, 2014, 11:05 PM
I often use the Wilton "bullet" vise on my benchtop for pins, sights, etc.

Bill Jacobs

July 16, 2014, 01:05 AM
Pins are either retained or held by the mechanism they're installed in - remove one part and free 3 or 4 others. Many older firearms used pins that were simply press fit all the way through the frame to hold parts, sometimes lightly staked over and a tight interference fit. On those you need an arbor press. They were fitted like they never ever intended for them to come again. Some of them never moved in 100 years or more. Get a big enough press and they'll come out with no damage.

July 16, 2014, 07:10 AM
Thank you for your replies, folks.

July 16, 2014, 11:00 PM
An arbor press requires some kind of fixturing setup to do the job correctly, if one cares about the final result (which will be superior to the hammer method). Most don't have the inclination or time for the setup. And, a drill press can often substitute for the arbor press.

July 17, 2014, 04:05 AM
An arbor press requires some kind of fixturing setup to do the job correctly, if one cares about the final result (which will be superior to the hammer method). Most don't have the inclination or time for the setup. And, a drill press can often substitute for the arbor press.
Very true. Using the 4-jaw on the lathe, I bored a deep hole in the quill of my arbor press to accept not only brass and aluminum soft jaws, but standard diameter (hand) punches as well. A small 1/4-20 thumb screw secures the punch. It's come in handy for pressing small bearings and whatnot over the years, so I was wondering why it couldn't be used for pushing out pins on guns.

July 17, 2014, 01:18 PM
a drill press can often substitute for the arbor pressA very interesting idea ... I shall have to give that a try. Thanks! :)

July 17, 2014, 03:52 PM
If you only need light pressure a drill press may work. Most all I have used do not generate a lot of force. A punch and hammer works better than a drill press.

July 17, 2014, 03:54 PM
Obviously ... but for some things ...

July 17, 2014, 04:40 PM
american motto,if all else fails,use a bigger hammer

Jim K
July 23, 2014, 01:43 PM
In the old days, when round-end pins were very common in firearms, the factories did use presses to install them. The punch had a concave end that matched the pin so as to not mar it.


July 24, 2014, 02:47 AM
I like the idea of a hole in the end of the ram. I have a ratcheting 5 ton hand press in my shop, but I think a 1/2 ton or 1 ton would do better.

With a tight tolerance ram and something like a pin vise with close fit into such a hole would allow the pin to be started using the pin vise jaws to hold the pin from tipping sideways for the first fraction of the insertion, then once it's started the pin vise could be taken out and the end of the ram used to send it home.

My experience with pushing long thin rods into holes without any means to keep the pin vertical is that most arbor presses have enough slop that the slightest bit of non-alignment will cause the arbor ram to move sideways far enough to exacerbate the difficulty, and add to that a receiving frame not secured against sideways movement and you have a good method for scratching up a gun.
Videos I've seen of guns being assembled by the makers have shown them tapping the pins in with a hammer, though I'm not trying to imply that presses aren't used by some.
A hammer and solid foundation under the gun, plus experienced hands, works very well indeed. I've driven many pins in Sigs that are true interference fits using a small ball peen. My experience with the Sigs is that getting them out is much more difficult than getting them back in.

July 26, 2014, 07:47 PM
Any decently fitted machine shop wil have an arbor press.
And gauge blocks.

The two of them allow you to rather quickly 'jig up' for just about any task needed.
I have a large hydraulic Marlboro press and a small bench size mechanical press.
Add a dial indicator and you can move a sight a few thousandths of an inch reliably. Or hammer it back and forth.

A drill press is only around 16:1 for mechanical advantage and cannot develop all that much force.
To grind through glass I hang a brick on the arm at about 6 inches on the handle and let it work at low RPM on the drill press in a water bath.
Brass tubing with teeth in the end and a putty ring if the glass piece is large.
Around 400 grit silicone carbide powder. Clover compound makes a mess from the oil. Abrasive and water in a paste.

Hammers are easy to find.
Make sure the punch nose matches the pin in any case.
A diamond burr and a few minute to match it up does wonders.

July 26, 2014, 09:03 PM
The Greener No. 2 used to be a staple in gunsmithing and machine type shops.

There probably isn't a huge need for an arbor press when working on ARs and 1911s.
Which if I had to guess is what a majority of gunsmiths probably work on.

Not saying there aren't artisan type gunsmiths anymore.

July 26, 2014, 10:00 PM
Sometimes, usually, a sharp whack from a hammer & punch will break loose a tight pin or sight that a slow press won't until something is damaged when it does break loose.

Thats why I still use a hammer and correct punch type for tight pins & sights.


July 27, 2014, 02:17 PM
If you compute the forces involved with a hammer and punch even a small 'tap' produces VERY large numbers.

You are at the point that even steel starts to deform unless it is at its very hardest state (and then it often has brittle failure).

30,000 gs and up is not all that hard to generate.

July 27, 2014, 03:26 PM
An arbour press costs far more than a hammer.
"...if all else fails..." That's not American. It's a weapons tech adage.

August 3, 2014, 03:58 PM
Arbor presses are used quite often when you have the ability to set them up properly. I use one with a brass tip to install 1911 sights all the time and have used them in the past for pins and such. The difficult part is making the jigging to hold some of the work.

The amateur gunsmith probably can't justify spending the coin for the press and making fixtures when a hammer, punch and vise is easier to use but it's so much less damaging to install sights with the press.

August 3, 2014, 07:22 PM
Great discussion, thanks for the input all!

August 8, 2014, 02:55 AM
It's because my arbor press is waaaaay over there and the hammer is always right here.

No really, holding a punch or drift under the ram of my arbor press is a pain.

Willie Sutton
August 8, 2014, 09:00 AM
I must be different... I use the quill of my Bridgeport for precision pin installation, chucking the pin in a Jacobs chuck to keep it aligned. For any thrust needed for a firearms pin you can exert enough force on the quill with ease.

Drill Press would be a poor mans alternative.



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