Cylinder pin to barrel play 1851 Colt

[frankjg]

I have a Colt 1851 with quite a bit of play (2-3 thousandths. It is a Colt 2nd gen "C" series and its in nice condition. Anyone know the measurement of the pin diameter. Not really sure if its worth fixing.

Thanks

Frank

[Wolfgang]

Frankjg,... the "Colt Forum" might be a better place to look fur this info,..... 

[Mako]

I have a Colt 1851 with quite a bit of play (2-3 thousandths. It is a Colt 2nd gen "C" series and its in nice condition. Anyone know the measurement of the pin diameter. Not really sure if its worth fixing.

Thanks

Frank

Frank,
The Arbor diameter where the cylinder rides is nominally  Ø.430.  That is from one Gen 2 revolver, two Original Colt's 1860s and 14 Uberti revolvers which share the same dimensions.  Uberti made many of the base parts that were finished in the U.S.  I have heard mixed reports on the arbors, but I believe those were made in the U.S.  they have the features of the original 1851, 1861 and 1860 pins.  This includes:

• The size and pitch of the helical relief groove
• The hand clearance cut on the Uberti is an angled cut on the port side.  The Colt cuts are symmetrical flats that look like "wrench flats."
• The location of the fouling clearance on the 1860 at the front of the cylinder. (Uberti makes only one which is optimized for the Navy models, but uses it on all Belt Model Percussion Pistols). 

I have also noticed that most if not all of the Colt's 2nd Gen arbors were Color Case Hardened.  With the Ubertis it is hard to tell.

The cylinder to arbor fit is not a "precision" running fit.  The average for the through hole diameter is actually Ø.438.  I checked my spread sheet when I got home and the average is actually Ø.434.  With a good film of lubrication this would limit the clearance a bit, bit it is still .004" .002"per side.

You don't want a tighter fit than that, with a bit of fouling the cylinder will stop rotating. a good coat of grease on the arbor pin in the helical relief will keep you running.

Do you have anyway of taking accurate measurements of your arbor diameter and your through hole?

Regards,
Mako

I reviewed the spread sheet and remeasured the Colt's 2nd Gen this evening:
The arbors run a range of Ø.427 to Ø.431 with the average being Ø.430.  The cylinder holes run from Ø.433 to Ø.436, with the average being Ø.434.  The loosest fit I have is an almost new '60 with an arbor diameter of Ø.428 and a cylinder bore of Ø.436.  The tightest is an 1861 with an arbor of Ø.430 and a cylinder hole of Ø.433.  The Colt 2nd Gen is an arbor of Ø.429 and a cylinder hole of Ø.434.

[Mako]

Frank,
I double checked the numbers I gave you earlier and I was correct on the arbor diameter, but I was off on the cylinder through holes.

I reviewed the spread sheet and remeasured the Colt's 2nd Gen this evening:
The arbors run a range of Ø.427 to Ø.431 with the average being Ø.430.  The cylinder holes run from Ø.433 to Ø.436, with the average being Ø.434.  The loosest fit I have is an almost new '60 with an arbor diameter of Ø.428 and a cylinder bore of Ø.436.  The tightest is an 1861 with an arbor of Ø.430 and a cylinder hole of Ø.433.  The Colt 2nd Gen is an arbor of Ø.429 and a cylinder hole of Ø.434.

Regards,
Mako

[frankjg]

Thanks MAKO

That is exactly the info I was looking for.

Now for me to get my calipers out.


Frank

[Norton Commando]

Frank,

How are you going to measure the hole in the cylinder? A vernier caliper will work, but it's not the most accurate for this application.

Just curious...

[Professor Marvel]

Frank,

How are you going to measure the hole in the cylinder? A vernier caliper will work, but it's not the most accurate for this application.

Just curious...

One can easily slug it (like slugging a barrel) and measure the lead slug, or make a paraffin casting, push it out with a dowel,  and measure the casting as one would a chamber casting.

yhs
prof marvel