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Valve grinding


vibrac

Well Known and Active Website User
VOC Member
Does anyone do their own valve seat grinding nowadays? And where can you buy individual stones UK especially when most are car ones at 45 degrees.making a stem to hold it with an opened out top guide was the way we used to do it. (hells teeth that was a long time ago!)
Not just Vincent question I have a particularly difficult 20s side valve I need to make my own stem for again a single stone though I suppose a cutter would work on cast iorn
 

erik

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VOC Member
I htink with a Hunger machine it should be possible ? but i have no!
 

oexing

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VOC Member
I do all seats with the Hunger system but that does not help you. Did you have a look into Ebay, there are lots of valve seat cutters ? Depends on how much you want to spend. The Neway cutters look great but I would insist on more than 3 blades for correct geometry. Five blades are acceptable, seems you´d have to get a whole set for that type. There are cutters with a lot of carbide blades brazed in the cutter head, very low price. I´d believe these to be better than the old type of file tooth cutters made of hardened steel.

Vic
 

Cyborg

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VOC Member
If you can find someone locally who has the complete setup, you could get them to redo a stone to 30 or whatever you are looking for. I looked for a large enough 30, but just ended up finding something close to the correct diameter and truing it to 30... which you could do in a lathe with a diamond tool ... just have to protect the bed etc from the mess. I used Neway long ago and found them a little tricky to get a decent finish depending on how hard the seat was...although I don't recall how many blades they had.


Valve seat grinder .jpg
 
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vibrac

Well Known and Active Website User
VOC Member
I wonder about cutters I know uncle Ron always used a stone
 

oexing

Well Known and Active Website User
VOC Member
The dressed stone grinder will work OK but with cutters look for minimum 5 blades like some Neway types - or else you risk chatter and poor contact faces when trying the valve on them. Possibly you could get these Indian or Chinese brazed multi blade cutters to produce a reasonable finish, and anyway, most likely the valves get lapped with grinding paste for checking the seal.
The Hunger manual seat cutter has a 45 degree automatic feed head, 30 degrees available, so I do not need any lapping after that. The accuracy cannot be bettered with any other system and is extremely adaptive for very small valves and big ones the same. You do all correction angles to set seat width from top and in the channel too.
We had a set of seat cutters from China recently that has single cutters with all angles finishground in the single blade, same type of blades like with SERDI machines. That works quite well, provided the jig is mounted as it should and with a few turns on the handle you are almost ready to go, not much grinding in the valve is needed. In the link below there is a video clip showing the operation. But then, this does not help much in this thread , but in case someone is looking for that type of workshop equipment I can recommend this set for motorcycle jobs.

Vic

Link to Aliexpress:
Valve Seat cutter

P1060450.JPG


P1060435.JPG
 
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Cyborg

Well Known and Active Website User
VOC Member
Best one for bikes that I came across was a Japanese made setup that looked similar to a die grinder. Small, light, and like the larger ones had a spring holding the stone off the seat, so it was easy to just do a very light skim. The grinder that belongs to that piece of equipment in the previous post does a good job, but it would nice if it was a little lighter and more compact. I tried making one from similar air powered driver with a clutch (originally set up to run spoke nipples in at an alarming rate of speed...not to be used with stainless), but couldn't get the RPM required.
 
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oexing

Well Known and Active Website User
VOC Member
That would be allright for just a little bit of resurfacing seats but I would not want to grind for days all-new rings with them. So the China set above would do , the Hunger set certainly.
How would you do the correction to reduce seat width to 1.5 mm ??

Vic
DSC00015.JPG
 

litnman

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VOC Member
A Hall Toledo seat grinder. This is what Marty Dickerson used on his bikes.
The stone turns at 10,000 rpm while the eccentric spindle turns at 20 rpm. Only a few degrees of the stone contacts the seat while grinding.
Hall seat grinder.JPG The special mandrel fits both guides.
 

Cyborg

Well Known and Active Website User
VOC Member
Same way you would with the cutters... 3 (or more) different stones e.g. 60 45 30.
I had never heard of the Hunger unit. Looks very nice. One for sale in Washington State not too far away, but not cheap and I don't do enough seats to justify adding it to the wish list. Not a lot of seat replacement done with motorcycles back when I was in the prairies. Much lower milage due to winter hibernation.
 

litnman

Well Known and Active Website User
VOC Member
With the Hall Toledo I can take cuts of .0005" or less. The stone come 30, 40 and 60º and in three grades. The diamond stone dresser operates the same as my Souix stone dresser. For a machine 75 years old it still does an excellent job.
 

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