Mystery Tool 9-551

[miken]

Hi, does anyone know what this tool is? I think it is like a miter gauge adjustable stop for making repeated cuts the same length on a table saw. It has a part number stamped on it 9-551 and it fits on the bed of my Atlas 12" lathe. I can't find the part number in my Atlas accessory catalog. The part number format matches some of the numbers in the catalog i.e. 9-XXX, but it skips over 9-551. Google isn't helping.

Thanks for any info.
Mike -

[SteveM]

It looks like some kind of adjustable stop for round rod, but I can't imagine how it would be used on a lathe.

With changing diameters of work pieces, the height of the tool would have to change, but this is fixed in height.

Steve

[miken]

It looks like some kind of adjustable stop for round rod, but I can't imagine how it would be used on a lathe.

With changing diameters of work pieces, the height of the tool would have to change, but this is fixed in height.

Steve

That's what I was thinking as well, but ddillman over on the hobby-machinist website found it for me in a 1940's Atlas catalog. It is a valve stem grinder attachment of some sort. I have no idea how it was used, or if I could ever use it for anything. One more unused tool in the shop wont hurt me any.

[NP317]

That's a new one for me!
And I owned/used an Atlas 12-36 lathe for several decades.
RussN

[miken]

First it was driving me crazy that I couldn't figure out what it was, now its driving me crazy that I dont know how it was used.

[Bill Shields]

Well ..start from the picture...and work backwards

It appears to bolt to the ways like a tailstock ..so whatever the function...it does not appear to move once set up.

My guess is that you use it with a tool post grinder

Think tool cutter grinder not lathe

[John Evans]

Well if you read the fine print it was used with the 450 and 10-450 GRINDERS!

[miken]

I'm new to machining so its not obvious to me. I watched some videos on YouTube about valve grinding but they all were about grinding the seat, not the stem. I was thinking you need to rotate the stem while grinding but the v blocks sit way lower than the lathe spindle center, so that doesn't make sense. There doesn't appear to be a way to secure the valve stem to it either. I have the grinder but have yet to use it. The advertisement also shows what looks like a tool post and maybe a collet type thing. It doesn't appear to mount onto the grinder, but I could be wrong. I assumed it mounts to the bed.

Edit: I'm thinking it doesn't hold the valve stem at all. Maybe it is used to align the grinding wheel to the stem mounted in the lathe somehow? Maybe the centering pin arbor sits in the v blocks?

Thanks for the help.
Mike

[Mr Ron]

According to the attachment, it is meant to be used to grind "VALVE STEMS" and "CUTTERS", meaning cutters used to reseat valves . The index finger is used to index the cutter according to the number of flutes. I don't think the lathe spindle was involved at all, only the bed to mount the attachment and the tool post grinder.

[John Evans]

Better that even chance it was NOT used on a lathe . But if it was you would grind on the side of the wheel well away from center line. Some early automotive engines did not have provision to adjust valve clearance in service. Ford flathead was a prime example ! You ground the valve seats in the block ,put the valve in and checked the clearance . Then you ground off the end of the stem to get the correct clearance. You screw up and that off to much !! Then you grind the seat a little deeper !!!! That system held the clearance pretty well until the next ring and valve job was due. THAT happened somewhere between 20,000 and 30,000 miles. And Mr. Ron very well may be correct that it was used with a tool post grinder. We need to see what those grinder numbers looked like !

[Mr Ron]

With further searching, I found out that the attachment was used only to square off the end of the valve stem. Although the valve held in the attachment was not at the lathe's arbor center, a grinding wheel mounted on an arbor in the lathe was used to grind the valve stem end using the flat side of the wheel. Further valve stem work was used with a precision chuck mounted to the lathe arbor (a 4-jaw chuck would work) and a tool post grinder used to grind the mating angle on the valve face. The fixture was also used to grind the cutter reamer for the engine valve seat. The cutter mounted on an arbor and held in the fixture, indexed by the index finger was ground using the tool post grinder. Grinding valves in a lathe was not the most direct way. That is why dedicated valve grinding machines were developed and used to this day.

[miken]

Thanks guys, I appreciate the info. To John's point, I watched a video where the person used a special valve grinding machine to first grind the angle on the valve, then he would grind the end of the stem to shorten appropriately.