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drilling and tapping the yugo m48
- Thread starter TrueBrit
- Start date
Are you thinking of a do it myself project?I do not intend to be disrespectful,but find a gunsmith who has a vertical milling machine such as a Bridgeport.
It is not that it is a difficult job,it is pretty simple.There are a surprising number of ways it can be messed up badly
I can't teach you here.
It is not that it is a difficult job,it is pretty simple.There are a surprising number of ways it can be messed up badly
I can't teach you here.
OK.The first thing you need to do is get set back up where ever you drilled the hole,and you need to be exactly centered over the hole.I use a tap wrench that has a floating dowel pin in the back end of it.The dowel goes in the machine spindle.In this way the tap wrench spins around the dowel,and is free to travel up and down with the tap.It is critical tha the tap goes in straight and centered and stays that way.Lean it over just a little and it will break.
Use a good tap lubricant.I like Rapid-Tap or Tap Magic;About every 1/4 turn of progress,back the tap out a bit more than 1/4 turn to break off the chip.At least a few times per hole,take tha tap all the way out and clear all the chips out.The chips binding up is another way to snap a tap.When you begin cutting with a new,sharp tap,you will feel a certain torque requirement and a small amount of spring in rotation.Be sensetive to that feel.Any increase in torque or spring is danger.Use extreme cautiion with the chips when using the bottom tap. Good luck.
Use a good tap lubricant.I like Rapid-Tap or Tap Magic;About every 1/4 turn of progress,back the tap out a bit more than 1/4 turn to break off the chip.At least a few times per hole,take tha tap all the way out and clear all the chips out.The chips binding up is another way to snap a tap.When you begin cutting with a new,sharp tap,you will feel a certain torque requirement and a small amount of spring in rotation.Be sensetive to that feel.Any increase in torque or spring is danger.Use extreme cautiion with the chips when using the bottom tap. Good luck.
OK,so you are drilling and tapping through a bushing,and I assume you had a bushing sized for the tap drill,and you have changed bushings to allow the tap to go through.Do use an appropriate bushing to guide the tap.
Assuming you have the right size tap drill,I will ask,was your tap drill made of High speed steel or carbide?If you did not need carbide to drill the reciever,then a regular high speed tap should have no hardness issue.
Case by case,generally in my experience Mausers are spot hardened where they need to be hard,but the receiver rings are (to my knowledge) not generally case hardened.
So,now look at your tap.Is it a taper tap,a starter tap,with a long taper on the tip?Might the tip be contacting the bottom of the hole?That sure can be an issue on a shallow blind hole.Then,do you have a plug tap and a bottom tap?Try the plug tap.Does it bite? you won't get real far before you find the bottom.You can get in real trouble when you contact the bottom.Beware of chips,and feel for contacting the bottom.Then come back with the bottom tap,that square ended one,to finish.It is easy to chip off the lead tooth.Don;t.and if you do,it may lock up the tap.If that happens,stop,write us again.
Sometimes there is an advantage to grinding the non-cutting useless part of the tip of the tap off.Clear the chips often.
Assuming you have the right size tap drill,I will ask,was your tap drill made of High speed steel or carbide?If you did not need carbide to drill the reciever,then a regular high speed tap should have no hardness issue.
Case by case,generally in my experience Mausers are spot hardened where they need to be hard,but the receiver rings are (to my knowledge) not generally case hardened.
So,now look at your tap.Is it a taper tap,a starter tap,with a long taper on the tip?Might the tip be contacting the bottom of the hole?That sure can be an issue on a shallow blind hole.Then,do you have a plug tap and a bottom tap?Try the plug tap.Does it bite? you won't get real far before you find the bottom.You can get in real trouble when you contact the bottom.Beware of chips,and feel for contacting the bottom.Then come back with the bottom tap,that square ended one,to finish.It is easy to chip off the lead tooth.Don;t.and if you do,it may lock up the tap.If that happens,stop,write us again.
Sometimes there is an advantage to grinding the non-cutting useless part of the tip of the tap off.Clear the chips often.
Mauser receivers are carburized. Not exactly like case hardening, but pretty close.but the receiver rings are (to my knowledge) not generally case hardened.
Then,do you have a plug tap and a bottom tap?Try the plug tap.
There ya go!Clear the chips often.
Gunplummer
New member
Use a carbide spot drill or a drill slightly larger than the tap to break through the cased area around the hole. It is only about .015- .020 deep. If you don't the tap is still fighting its way through the thin outer skin. It should appear as a slight chamfer around the hole you already drilled.