Gunsmithing Winchester Extractor Cut

[Messmaker]

I am going to be blueprinting my first Winchester Mod. 70 and need some help on the conical bolt counterbore and extractor cut. Please give me details on how you do this or if you have a factory print would be great as well. Do you just use the extractor cutter and 96 degree counterbore from PTG?

 

[Gene Poole]

I didn't know PTG made a counterbore cutter for the cone breech. I may have to check it out.

I've always just cut the cone with the compound. For the extractor cut, I have a PTG tool, but I've never used it. I've always just used a woodruff cutter. The PTG cutter has a curved profile that I've never actually seen on any W70 takeoff barrels. They've always just been a straight cut so that's why I've never used the PTG. If you want, I'll sell you my PTG. [IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/lh3.googleusercontent.com\/snE-jc29UnNWEua1BD5cJ9LcpUPsWaJGtgFtzmKJEbbFTDq7rvLCkinPb9_A9jgZZ95fMKFYXg2gga8EveFT9mNof-pYO68sOPULljNGPNWkbVA9H16C4ljSLbCElM6oAy_SKFGIdKQ6_lUJG8KTzItcTTI7ZZw3zSBkun6Rxj4aFAapax67KtnRke9Sbv8h2PDjxCptYscDTPZVtvJMJoAyMI5b0kQOMe3qVrYTVTZaSAhbtjUwyyBB9oL67ja0SwZMe0fNZYBDonyEfcTcjEMclhScdp2J5Jizj4DpbWr6qSjzK_TVL6uxyr_mybZLI9VMZ3QQloSVgQQ9rjYSkR2lV-H4t_dnYhS2PDGWu2E0LIwXss_jksWPzGrgwdtKHfF7v5wcF_XV75CXhBxbsCzgkds7lUdWogMIE1kbVNtRUVaBbBswpQNikgQosxshSAIXHyyzxQKgtiil0dCNhOh9MKWCfKiWNkgCefSpqG91NQtauZ8_3P8_XPPVx0UiqDbD_ZyS7hWvP9uPbB_t5WsgXymTnvDLDvCQ2-j-aztYk74dhOInyBxSTurtIGgQQ0sULV0DNqBtbtPbPsJuon_9tN12a5gha6nWQ7C40ZUUN41FdMFDHg=w1024?.jpg"}[/IMG2]


[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/lh3.googleusercontent.com\/ka1nyBsBFHBzWUxu3lEQkA-msSSnGEf25NVDRCUNRAes0wqJumxVCv3ZMon8jRwY3QxhNon3Noj72bax-dIFCwUYEFLWuVgHAbeyLdT5y4NXLITYErJ2Q1wCyAhefhwATcASLFoOWCnRASojOWT0eLMfMN4L-TCgN6wR4kCL-YpqgpWVcyN_MqnZ6Mu_WpdwEfA8uCgJ7rzg1zhbkDwubQLZW-q-yFkkYbvi2pdN_cdCKtY_D-JxRcHENBnsz8L1jXMRXEwbT39IHKN3isIfChZeK7SQI1aZfv0mjfUgXA6VVbn-b7OtscJQcfC8dIoyzNykUENhHqNBI1DNDeh2YZcsiKvq7A9KT-r1MESZF1fbVyZ1CGEYppS2RLbBC4Yt2SH-7MsK2efkqMcSzuQWX7dUqiH3yczHFUSnAmaQY5a6TuaqE44vkNMYO4gXYJQoZp3fDATk8jw32P3ua-hWoojsU8etSX3gzlfKciN3wcAs2zqNLVPsgCmqzijRQ2BhdooSo3WcSo6awO2ua8ZvzsNtCh2tYQdW17qrnMs3e2HEW0yqHhNe5zsYQJbA6LCItFA6WU3_BjGJzRt6Iln6AETm0JVtooGn4DSISgYKeMyBteYKiGOz9Q=w1024?.jpg"}[/IMG2]

Here's my never used PTG cutter:

 

[Messmaker]

I didn't know PTG made a counterbore cutter for the cone breech. I may have to check it out.

I've always just cut the cone with the compound. For the extractor cut, I have a PTG tool, but I've never used it. I've always just used a woodruff cutter. The PTG cutter has a curved profile that I've never actually seen on any W70 takeoff barrels. They've always just been a straight cut so that's why I've never used the PTG. If you want, I'll sell you my PTG.
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Here's my never used PTG cutter:

Thanks for the info. What angle do you set you compound at?

 

[Gene Poole]

The cone angle is 96° so from the bore centerline it is half that, or 48° Depending on how your compound is graduated you'll need to set it at either 48° or 42° depending on whether it measures from centerline or faceline.

 

[Messmaker]

Thanks. Do you dykem the counterbore then run the bolt into it to mark the cut for the extractor?

 

[Gene Poole]

Thanks. Do you dykem the counterbore then run the bolt into it to mark the cut for the extractor?

No. I applied the dykem then torqued on the action, then slid a piece of 1/8 keystock, sharpened like a chisel on the end so it would etch the dykem, down the raceway top and bottom to mark the counterbore. I read someplace that the width of the slot was supposed to be 0.410 and this was consistent with the takeoffs I had on hand so I split the difference between the dykem marks to get 0.410.