Ronin Posted January 13, 2015 Report Share Posted January 13, 2015 Im in the process of doing a complete refurbishment of a Sako AV for a customer. Im also doing a bit off "back to basics" machining using my 4 jaw chuck instead of the 6 Jaw Bison, as thats being stripped down and totally cleaned today. I clocked up the new barrel for the AV and chambered it using one of three chamber reamer holders I have - this time I chose my Gre Tan holder as the barrel (a chromoly Lothar Walther) was showing zero run out despite being a rather light (Standard Sako) profile - its real easy to distort the lighter profile barrels when clocking them up. I check for concentricity at every step - create tenon; check, create thread; check, create bolt nose recess (if applicable); check and so forth right up to the chambering phase. Anyway, once id chambered the barrel to headspace plus .003" I checked the rearmost edge of the chamber for run out. Dial gauge is an Interrapid in 1/10000 increments (one ten thousanth of inch) The tenon and chamber are still wet through from the flush system I use which is why its so messy…. I usually recon on getting 2- 3 tenths run out on most chambers and as close to zero on target or tactical rifle chambers - I'm more than happy with this one…. http://i20.photobucket.com/albums/b246/Redmist1/th_IMG_2414_zpslzgkhr0n.mp4 Link to comment Share on other sites More sharing options...
Danpd Posted January 13, 2015 Report Share Posted January 13, 2015 Great stuff Andy. Might be time for one of these..... http://shop.idealprec.com/products/brown-sharpe-bestest-599-7033-5-00005-008-dial-test-indicator Link to comment Share on other sites More sharing options...
techno_brat Posted January 13, 2015 Report Share Posted January 13, 2015 Hi, Great work there, i'm interested in the setup you use, any more pics of the process? And how comes the you use different reamer holders? Cheers Jack Link to comment Share on other sites More sharing options...
Offroad Gary Posted January 13, 2015 Report Share Posted January 13, 2015 I've got a couple of video's like that, not the same without the voiceover from "mr zero runout"!! Keep up the good work Andy. Link to comment Share on other sites More sharing options...
Ronin Posted January 13, 2015 Author Report Share Posted January 13, 2015 Great stuff Andy. Might be time for one of these..... http://shop.idealprec.com/products/brown-sharpe-bestest-599-7033-5-00005-008-dial-test-indicator You tempt me too much!! Link to comment Share on other sites More sharing options...
Ronin Posted January 13, 2015 Author Report Share Posted January 13, 2015 Hi, Great work there, i'm interested in the setup you use, any more pics of the process? And how comes the you use different reamer holders? Cheers Jack guess I've collected a few over the years. Ive a couple of hand held reamer holders - Bald eagle and another brand which escapes me and the Gre Tan which is held in the tailstock of the lathe - this (tailstock) needs to be properly adjusted to get the best from the holder - I guess the barrel also needs to be clocked correctly too….. Link to comment Share on other sites More sharing options...
Ronin Posted January 13, 2015 Author Report Share Posted January 13, 2015 I've got a couple of video's like that, not the same without the voiceover from "mr zero runout"!! Keep up the good work Andy. I do try to maintain a standard Gary,,,,you must be due another rifle soon ……. Link to comment Share on other sites More sharing options...
techno_brat Posted January 13, 2015 Report Share Posted January 13, 2015 guess I've collected a few over the years. Ive a couple of hand held reamer holders - Bald eagle and another brand which escapes me and the Gre Tan which is held in the tailstock of the lathe - this (tailstock) needs to be properly adjusted to get the best from the holder - I guess the barrel also needs to be clocked correctly too….. You're too modest lol. But with work like that i suppose you have to be thanks for that info, i'm learning to use my dads lathe and find it all pretty interesting. Do you have any pics of your chambering process? I would just be interested to see how it's done. What lathe do you use? I have a lovely vintage(but accurate) colchester master. How do you go about dialing the bore in? Many thanks Jack Link to comment Share on other sites More sharing options...
baldie Posted January 14, 2015 Report Share Posted January 14, 2015 Andy, I doubt you are getting a true reading. Turn the lathe on at a reasonable speed that won't damage the needle indicator. All centre lathes that are probably in use barrelling guns will have 0.0002" at least , runout in their head bearings. If they didn't, they would seize up. The clearance is there to allow oil to freely move around them. It will only show under load. Only the very best machines that are in use for medical work etc run tighter tolerances, and no one uses them for fitting barrels. Link to comment Share on other sites More sharing options...
Ronin Posted January 14, 2015 Author Report Share Posted January 14, 2015 Some centre lathes clearly have better tolerances than others. Under power, chambering speed - still sub 2/10ths (.2 ten thousandths of an inch) run out - thats with the bearings cold as I took the footage this (chilly) morning. Ive seen videos from several other rifle smiths - Tooley, Paddy Dane, Mik Maksimovic, Jim Borden, Speedy Gonzalez, Gordy Gritters etc etc etc who also show zero or almost zero run out on chambers when set up with dial indicator at rear of chamber under load. I don't think its unusual personally, its a tolerance standard I like to have and hold to wherever possible in all my builds. Hope the link works as its my first posted video on U tube Link to comment Share on other sites More sharing options...
Ronin Posted January 14, 2015 Author Report Share Posted January 14, 2015 You're too modest lol. But with work like that i suppose you have to be thanks for that info, i'm learning to use my dads lathe and find it all pretty interesting. Do you have any pics of your chambering process? I would just be interested to see how it's done. What lathe do you use? I have a lovely vintage(but accurate) colchester master. How do you go about dialing the bore in? Many thanks Jack There are loads of videos on Viemo / You Tube of people dialling in, chambering and machining - suggest they would be a good place to look at and learn. There are also a number of good books available through Brownels etc on rifle building / gun smithing. Its not a "black art" as some would suggest, its in the main basic first year apprentice engineering - unless of course you have access to CNC machines where some degree of computer skills are also worthwhile. Some rifles are simple mechano builds, where items can be bolted together, others take more skill. My lathe - is a simple GH1330, which has been "customised " and adapted over several years to allow me to work to pretty fine tolerances and make accurate rifles and I've had a little help from one of the finest smiths in the country along the way to steer me in the right direction. A simple hobby thats developed into a part time business, driven in the main when I was taken for a ride by a rifle builder ten + years ago…... Link to comment Share on other sites More sharing options...
Big Al Posted January 14, 2015 Report Share Posted January 14, 2015 I usually recon on getting 2- 3 tenths run out on most chambers and as close to zero on target or tactical rifle chambers - I'm more than happy with this one…. Have you ever built and tested a rifle for accuracy that has 1-2 thou run out as opposed to 2-3 tenths of thou run out? I can understand and respect a persons desire to work to the smallest tolerances, however I do wonder how much it really matters in terms of how the rifle shoots to get things this close? There will be a point of diminishing return, have you established where that is in this respect? Link to comment Share on other sites More sharing options...
techno_brat Posted January 14, 2015 Report Share Posted January 14, 2015 Thanks for that, yeah I have been on youtube, mostly americans and they don't go into too much detail. I wish there were more brit videos from the rifle builders! It's interesting to see how you lot create these fine rifles. I see what you man about the mechano rifles, I do love that about the AR15's, but there is something about hand crafting a rifle that is far nicer. Oh right, those Warco lathes look alright for the money. Didn't know they was that good! Did you need to do much to produce the sort of results you get? And as you say the basics are just simple engineering, but it's those important tips and techniques you pick up that make the difference. I hope to see more posts of yours and others work, I seeing them built as much as shooting them lol. Link to comment Share on other sites More sharing options...
Offroad Gary Posted January 14, 2015 Report Share Posted January 14, 2015 I do try to maintain a standard Gary,,,,you must be due another rifle soon ……. Andy, i only get another when i "NEED" one.... Got a spare slot for a .22 c/f though..... Let the "runout challenge begin", my business to the winner! Link to comment Share on other sites More sharing options...
tackb Posted January 14, 2015 Report Share Posted January 14, 2015 I wonder what the runout on brass is ? Link to comment Share on other sites More sharing options...
Big Al Posted January 14, 2015 Report Share Posted January 14, 2015 I wonder what the runout on brass is ? Yes, that was what I was thinking, I can't imagine people can reload to an accuracy of 0.0002" or even 0.001" for that matter Link to comment Share on other sites More sharing options...
Gandy Posted January 14, 2015 Report Share Posted January 14, 2015 It made me laugh that you moved the needle so people wouldn't call foul play. Don't know much about gun plumbing other than my rifle shoots well. Link to comment Share on other sites More sharing options...
1967spud Posted January 14, 2015 Report Share Posted January 14, 2015 Yes, that was what I was thinking, I can't imagine people can reload to an accuracy of 0.0002" or even 0.001" for that matter we strife to try some lapua out of the box +-.005 after neck turning and first firing +-.001 Link to comment Share on other sites More sharing options...
Big Al Posted January 14, 2015 Report Share Posted January 14, 2015 we strife to try some lapua out of the box +-.0005 after neck turning and first firing +-.0001 How are you holding the case and where/how are you measuring this? Are you are talking here about case neck wall thickness/concentricity? Considering that cases are in fact pressings with a little bit of rim turning I would be very surprised if they are made to anywhere near the kind of tolerances we are talking about on the chamber. Then again I don't know as Ive never looked that closely into it so always glad to learn. Link to comment Share on other sites More sharing options...
1967spud Posted January 14, 2015 Report Share Posted January 14, 2015 err i use a run out guge also called a concentricity gauge and yes im talking about run out at the neck of a turned case Link to comment Share on other sites More sharing options...
gbal Posted January 14, 2015 Report Share Posted January 14, 2015 we strife to try some lapua out of the box +-.0005 after neck turning and first firing +-.0001 I'm striving to avoid strife,nothing on TV So that is +/- .0005 after neck turning,which is meant to maximise uniformity on case necks? And +/-.0001 (still necks?) after the cases have been fire formed to a particular chamber neck-ie nothing really the human has contributed-I mean fire forming seems to have improved his work from .0005 to.0001 tolerance.And is this different ie better than brass from the box fired in a standard chamber? And the main cartridge case,not just the neck,in the chamber .....measures for that? Fascinating,if the data work out.I can see concentricity of bore/chamber is a factor,but a chamber difference of .0001 when brass is fire formed to it anyhow...I might be misunderstanding it completely,hence explaining my frequent .2s groups (the wind blew them all in) :-) I should add that recent posts advocating FL,rather than N only sizing,and upwards of 50 30-06 firings from one case suggest we look again at reloading best practices. Of course an accuracy of +/- 5% in an anemometer is tolerable,as our error is going to be 2-5 mph in wind reading. I imagine it's as much 'mind set ' confidence,as actual direct,.measureable holes on target effects;as a psychologist,these things are likely to contribute,perhaps beyond the .0001. Better to have it. gbal Link to comment Share on other sites More sharing options...
1967spud Posted January 14, 2015 Report Share Posted January 14, 2015 no before and .001 after Link to comment Share on other sites More sharing options...
tackb Posted January 14, 2015 Report Share Posted January 14, 2015 i'd be interested to know the case runout at the base where ronin was measuring , interesting stuff and I know that to strive for perfection is not a bad thing but I wonder if there was a test , how much out it could be at the base before accuracy suffered? Link to comment Share on other sites More sharing options...
baldie Posted January 14, 2015 Report Share Posted January 14, 2015 My chambers measure a similar runout of 0.0001 to 0.0002" , but are chambered , Outboard, i.e. the length of the barrel out of the chuck. I,ve chambered barrels between chucks on the same lathe and got the same figures. I don't believe them personally. I would,t run the lathe, warm, at chambering speeds for fear of buggering the indicator. The figures of 0.0002 to 0.0004" in the bearings are facts and are common to any lathe running an oil fed head bearing. This information came from a man who spent many years as a lathe builder at Colchester/Harrison and who services these lathes on a daily basis, and has been doing for over 40 years. He also happens to service most of the gunsmiths lathes in this country. people will know who I mean who know of him and value him. Those are factory spec figures and will increase on a used machine. They are also tolerances on english built machines, not ones from the far east. What difference will it make to a barrel ? Sod all. The runout on a factory barrel is horrendous by comparison, and they shoot. Nothing wrong at all with striving for perfection, its what makes excellent machinists , but accept some figures with a pinch of salt. Start stacking some of these tolerances up. A good fitting pilot on a reamer that isn;t too tight and allows oil to feed is going to have 0.0001" slop. They come in 0.0002" increments. A floating reamer holder will not put the reamer back exactly in the same plane every time, but this isn't measurable. Runout of AT LEAST 0.0002" in the head of a new machine. Explain to me then how a reading of 0.0001" can be taken as true, because I don't personally believe it, and my own barrels/practises show the same readings. Finally, I,m certainly not having a dig at you at all Andy This is very interesting and something I would love to get to the bottom of myself, the problem being how to measure it accurately without buggering instruments. Link to comment Share on other sites More sharing options...
1967spud Posted January 14, 2015 Report Share Posted January 14, 2015 just realtered my figures in past posts as id added to many 0's Link to comment Share on other sites More sharing options...
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