Valve seat cutters?

[ranger 1,783]

Just browsing a certain online auction site, saw these, and thought that these may be of interest? They are apparently for motorcycles and other small engines. Cutters are allegedly carbide, so should last a while? Price £22.99p, so not a huge amount. It would probably cost as much to have an engineering firm re-cut a couple of valve seats.

Edited January 31, 2023 by ranger

[ri702bill 9,008]

Are they turned by hand??

[953 nut 58,031]

I have a set of manual seat cutters that were old when I got them over fifty years ago. They don't have the abrasive stones, just the cutters. I have used them on small engines and automotive applications.

[Achto 28,809]

1 hour ago, ri702bill said:

Are they turned by hand??

 

Yes. The arbor holds the cutter true to the valve guide and the cutter is turned by hand.

[ranger 1,783]

58 minutes ago, 953 nut said:

I have a set of manual seat cutters that were old when I got them over fifty years ago. They don't have the abrasive stones, just the cutters. I have used them on small engines and automotive applications.

The old style carbon steel type cutters gained a reputation for losing their sharpness very quickly. This was generally a result of trying to cut seats that had ‘Work hardened’, (Hammered), over time. But if you first gave the seats a quick grind, with coarse paste, this removed much of the hardened layer and the cutters had a much easier life cutting the relatively soft cast iron. The carbide type cutters don’t suffer as badly from this.

looking at the design of these, I would think that anyone with a lathe could quickly ’Knock Up’ a tool the exact size they need for pennies and a little time spent. The inserts could be any carbide insert they have ‘laying’ around, (within reason’). Even new inserts are not horrendously expensive, (e**y). Body made to accept different size pilot pins to suit the size of the valve guide in question. And while you’re at it, make a reverse ‘image’ of the tool, with an internal taper to match the valve angle, a bore to accept removable bushes to suit the size of the valve stem, slots cut into the tapered face to allow the inserts to be adjusted to suit valve head diameter. Insert valve in tool, hold stem in cordless drill chuck, switch on and pull. It would probably only take a few seconds to reface the valve. Another good reason for owning a lathe👍

[ri702bill 9,008]

11 minutes ago, ranger said:

insert valve in tool, hold stem in cordless drill chuck, switch on and pull. It would probably only take a few seconds to reface the valve. Another good reason for owning a lathe👍

I grind valves in a lathe - a great visual check for run-out or bent valves. I use a low speed and blacken the ground edge  with a Sharpie, so I can see if the next process is even around the valve. Next part is operator dependant  - I use a new small fine grit sanding drum in a Dremel - wish I could find a decent affordable toolpost grinder. Turn the lathe on at slow speed, the Dremel on high. Angle the dremel in place and LIGHTLY have the sanding drum contact the valve, watching how the black disappears. Once done, a couple of go-rounds with the suction cup stick and the lapping compound. The contact area on the vavle ends up a consistant dark gray colored ring...

[ri702bill 9,008]

1 hour ago, Achto said:

 

Yes. The arbor holds the cutter true to the valve guide and the cutter is turned by hand.

Two things come to mind - the arbor has to be a good stationary fit in the guide, straight and perpendicular.

Hand cutting may only work as mentioned for light touchup work - a damaged guide needs to be either machine cut or ground.

 

McMaster sells mounted angled "tree shaped" stones - I have used the coarse to clean and the fine to get a decent finish. NOT to be done with a hand drill - we were given an old ShopSmith MarkV years ago - a combination of lathe, disc sander, tilt tablesaw and a drill press with a 3 FOOT throat opening. We leave it as an upright drill press - perfect to line up the block using a dowel or reamer, then the cutting stones. Hand lap the valve as mentioned...

Bill

[ranger 1,783]

3 minutes ago, ri702bill said:

I grind valves in a lathe - a great visual check for run-out or bent valves. I use a low speed and blacken the ground edge  with a Sharpie, so I can see if the next process is even around the valve. Next part is operator dependant  - I use a new small fine grit sanding drum in a Dremel - wish I could find a decent affordable toolpost grinder. Turn the lathe on at slow speed, the Dremel on high. Angle the dremel in place and LIGHTLY have the sanding drum contact the valve, watching how the black disappears. Once done, a couple of go-rounds with the suction cup stick and the lapping compound. The contact area on the vavle ends up a consistant dark gray colored ring...

I used to reface in the lathe with tct tooling, but now I have the ’Wolf’ re-facer + the seat grinding tooling. I also have the carbide seat cutters I picked up in a job lot at the local machinery auction for a very few £££s. No one seems to want this kind of kit nowadays.

As you already have a lathe, why not make a tool post grinder? If it’s  only for occasional use, standard type bearings would likely suit. Although bronze bushings may give less ‘chatter’ if well lubricated. Drive it via a flexible shaft from a high speed drill, etc. ER type collets and holders with straight or tapered shafts can be bought at reasonable cost, use one of these for the spindle, make the rest to suit your particular lathe.

[lynnmor 7,577]

The cutters shown are likely cheap imports and quality may vary.  If the cost is low it might be worth a try.  When using a carbide cutter, turn slowly to prevent chatter. 

 

I use Neway valve seat cutters, they are rather expensive but the carbide inserts are easily replaced.  I grind the valves on a surface grinder using a Harig Grind All.

[Achto 28,809]

1 hour ago, ri702bill said:

Two things come to mind - the arbor has to be a good stationary fit in the guide, straight and perpendicular.

Hand cutting may only work as mentioned for light touchup work - a damaged guide needs to be either machine cut or ground.

 

I have used Neway cutters for valve seats several times. I have always turned them by hand, never with a machine.

 

 

[ranger 1,783]

A couple of pics of mine.