I'm having problems cutting a seat on my Serdi, ..
It's a head I've been building for years, .. and the suppler won't
sell me the heads with-out seats & guides ( very poor customer service )
, .. so I've been cutting the really crappy exhaust seats they install,
.. they are hardened tool steel.
Yes, I know I should weld them out and put a good Iron seat in, but.
These things are hell to cut, .. dulls the cutter bit before I even get
1/2 way done. Tried cutting fast, very slow, .. dry, with different
fluids, .. mists, ..
Antbody have something I could try??
Cheers,
Curtis
machining tool steel valve seats
Moderator: Team
machining tool steel valve seats
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SchmidtMotorWorks
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Curtis,
I have cut a lot of hard tool steel while making plastic injection molds.
I don't know anything about Serdi but the grade of carbide that is good for iron will be too soft for hard tool steels.
If i rmemebr correctly iron is cut with carbide grades about C2 and tool steels like carbide like C6.
The cutting speed is a tricky deal if you can adjust it. If the cut is wide, you will probably need to slow it down but some very high hardness steels like M2 (high speed steel 62 RC) can only be cut at very high speeds with red molten chips.
If there is any way you can narrow the cutting contact area that will help. You can do that by grinding a notch in the insert and cutting to depth then put in an insert without a notch to finish it. This is if you have a way to grind carbide.
In hard tool steels, rigidty of the set-up is everything
I have cut a lot of hard tool steel while making plastic injection molds.
I don't know anything about Serdi but the grade of carbide that is good for iron will be too soft for hard tool steels.
If i rmemebr correctly iron is cut with carbide grades about C2 and tool steels like carbide like C6.
The cutting speed is a tricky deal if you can adjust it. If the cut is wide, you will probably need to slow it down but some very high hardness steels like M2 (high speed steel 62 RC) can only be cut at very high speeds with red molten chips.
If there is any way you can narrow the cutting contact area that will help. You can do that by grinding a notch in the insert and cutting to depth then put in an insert without a notch to finish it. This is if you have a way to grind carbide.
In hard tool steels, rigidty of the set-up is everything
Curtis,
What is your idea of fast?
I've cut Tucker seats (1.34" dia) at about 750RPM and the chips come off blue and stringy. It works great but I also know that as the cut gets wider the tendency to chatter increases by a significant amount. If you can rough cut with one cutter and then use another to just do the seat and top cut it will help a lot also.
SWB
What is your idea of fast?
I've cut Tucker seats (1.34" dia) at about 750RPM and the chips come off blue and stringy. It works great but I also know that as the cut gets wider the tendency to chatter increases by a significant amount. If you can rough cut with one cutter and then use another to just do the seat and top cut it will help a lot also.
SWB
Serdi sent me some info a while back on a new 8 degree positive cutter for seats above 45 Rockwell. They require different toolholder, different bit holder, and a 20mm top pilot. Maybe that would help you. So far I have gotten by with the older style cutters, and when it gets tough I go in first with an 82 degree single angle cutter, and follow with a light 35 degree top cut. Then I'm not taking as big of a bite with the 5 angle cutter.