Fitting a new bolt body.

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   So I've bought a new bolt body for my No1MkIII*. It has arrived and was still in the cosmoline grease. I've cleaned it and carried out an initial test of headspace with my original bolt head. Good news is that it refuses the No-Go 70 thou gauge well before the end of travel; which is good news because the old bolt body with the same head failed it miserably and barely passes the field 74 thou gauge.
Obviously I now need to carefully fit the bolt to suit the receiver, which will require stoning the lugs to get even contact, I have ordered a fine Arkansas stone for the purpose; I believe it should be better suited than the old half worn carborundum in my tool box.

Measuring the old bolt against the new one also revealed that the diameter is 2 thou larger on the new one, which will also improve the slop a little. So I'm hoping this will all have a positive effect on accuracy as well as case life.

When I'm testing the lug contact; what is the best way to load the bolt a little to reveal the contact?
I will use prussian blue paste; but was not sure if it's best to just pull the bolt back manually and operate it or to put in an empty case and put a bit of tap on the face to take up any slack and create a bit of load.
Any better methods? (that are known to work!) Let me know.

I'm hoping to get started on this over Christmas if the Arkansas stone arrives in time

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Zed Members Profile Send Private Message Find Members Posts Add to Buddy List Special Member Donating Member Joined: May 01 2012 Location: France Status: Offline Points: 6460	Post Options Post Reply Quote Zed Report Post Thanks(0) Quote Reply Topic: Fitting a new bolt body. Posted: December 14 2015 at 12:03pm
	So I've bought a new bolt body for my No1MkIII*. It has arrived and was still in the cosmoline grease. I've cleaned it and carried out an initial test of headspace with my original bolt head. Good news is that it refuses the No-Go 70 thou gauge well before the end of travel; which is good news because the old bolt body with the same head failed it miserably and barely passes the field 74 thou gauge. Obviously I now need to carefully fit the bolt to suit the receiver, which will require stoning the lugs to get even contact, I have ordered a fine Arkansas stone for the purpose; I believe it should be better suited than the old half worn carborundum in my tool box. Measuring the old bolt against the new one also revealed that the diameter is 2 thou larger on the new one, which will also improve the slop a little. So I'm hoping this will all have a positive effect on accuracy as well as case life. When I'm testing the lug contact; what is the best way to load the bolt a little to reveal the contact? I will use prussian blue paste; but was not sure if it's best to just pull the bolt back manually and operate it or to put in an empty case and put a bit of tap on the face to take up any slack and create a bit of load. Any better methods? (that are known to work!) Let me know. I'm hoping to get started on this over Christmas if the Arkansas stone arrives in time
	It's nice to be important, but it's more important to be nice!

Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: December 14 2015 at 2:04pm
	You're just loading it to measure, not actually fit, yes? I'd load a fired case with a bit of tin greased rubber sheeting on the rear face. Maybe even reduce the rim a tad or use a thin rimmed case to get "just a little pressure. If you wanted to go high tech cut a fired case in half, shorten it a hair & fit a spring inside to slightly force back on the rear face.
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)

Zed Members Profile Send Private Message Find Members Posts Add to Buddy List Special Member Donating Member Joined: May 01 2012 Location: France Status: Offline Points: 6460	Post Options Post Reply Quote Zed Report Post Thanks(0) Quote Reply Posted: December 15 2015 at 3:43am
	I need a reliable method of reading the lug contact. I will be fitting this bolt body to the rifle, so need a repeatable method to ensure I end up with a good contact on both sides; obviously stoning the high spot on the bolt lug until both are in good contact. I think that if I just pull the bolt back manually onto the lugs it may not be accurate, due to slight play in the bolt channel and the fact that the bolt handle is on one side, so not applying a centralised force as would a fired round. Maybe a spring loaded case is a good idea. Will have to see if I can make it work, I can test it on my other rifle which I know is properly matched to check the function prior to working on the new bolt. Can't afford to mess it up!
	It's nice to be important, but it's more important to be nice!

Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: December 15 2015 at 7:16am
	I'd fabricate ate spring loaded fired case myself. It shouldn't be hard to do.
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)

Zed Members Profile Send Private Message Find Members Posts Add to Buddy List Special Member Donating Member Joined: May 01 2012 Location: France Status: Offline Points: 6460	Post Options Post Reply Quote Zed Report Post Thanks(0) Quote Reply Posted: December 29 2015 at 1:00pm
	I have fitted the new bolt to the No1 MkIII*. Here are the original bolt (RH) and new (LH) bolt lugs compared prior to fitting. The lug contact of the original is obvious, and quite good. It is the overall head space that is on the upper limit; which is why I'm replacing the bolt. Here is the basic kit used. Prusian Blue, Carborundum and Arkansas stones,oil, Magnifying glass and a small piece of beer can to protect the shaft when stoning the lug face. To fit the bolt, I first used Prussian Blue to inspect the contact of the lugs. This was initially poor, as expected! The smaller lug having no contact. I used the Arkansas stone to carefully reduce the high spot on the RH (long) lug and repeatedly checked the contact using the "blue". I tested the bolt with and without the head; plus with a used cartridge to give some pressure to the lugs. The results do vary depending on how you do it. In the end I was getting contact on both lugs; not quite even at this point but a large enough area to be safe to test. I have to be careful at this point to not remove too much metal as the object of the exercise is to improve the head space. At present the head space is improved by about 5 thou. Just refusing the 0,070"gauge (instead of the 0,074"Field gauge) I have tested the rifle with 15 rounds of PRVI manufactured ammo, which is accurate in this rifle; but a little faster than my usual reload. Checking the lugs with blue afterwards showed contact on both sides, but slightly less contact on the small lug. I may tweak it some more but really only have 1 or 2 thou to play with. So will probably fire a few reloads and see how it performs.
	It's nice to be important, but it's more important to be nice!

Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: December 29 2015 at 2:30pm
	Nice tutorial, thanks! I'd fire some more rounds before doing any more periodically checking the fit & H/S as there is usually some initial set-back as the faces are subjected to recoil forces. AS you say, don't want to over do it.
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)

Zed Members Profile Send Private Message Find Members Posts Add to Buddy List Special Member Donating Member Joined: May 01 2012 Location: France Status: Offline Points: 6460	Post Options Post Reply Quote Zed Report Post Thanks(0) Quote Reply Posted: December 30 2015 at 10:36am
	I must say that I'm more student than tutor! I got the necessary information from the excellent articles by Peter Laidler and some additional info from Roger Wadham's book. It's not difficult; just needs some care and patience to go slowly and keep checking the thing after every few strokes of the stone. I used the Arkansas stone for all the work because the carborundum seemed a little rough for my liking on the initial go.
	It's nice to be important, but it's more important to be nice!

Shamu Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 20510	Post Options Post Reply Quote Shamu Report Post Thanks(0) Quote Reply Posted: December 30 2015 at 10:39am
	Yep, slow & easy is the trick. Just keep stoning away at the white bits till its all silver when you test fit.
	Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)