Vellubolt, by the Vellumoid Company, Worcester Mass. Google has been a complete strike out with the exception of a vague reference on an antique Ford chat site about oil pans. Brass with threads on one end, tapered with a groove on the other. When I first saw them I thought they were carb jets but that's not right. Anyone have or has worked with such things?

They were used to hold the oil pan on while you got the bolts started

I should make some for modern cars.   I do a lot of oil pans yet. A few models those would be very useful..

Used to have a set of Keep-Ups.   Tough little plastic items that did the same.  Slide it up into the threaded hole, about six of them on the average engine.  Slip the gasket over them, they would hold the gasket in place.  Then slide the oil pan on, this is all from the bottom side.  Put bolts in the other holes, then wiggle them a bit and they would come out.  Looks like this set would do about the same thing, very handy.

I have a drawer in my toolbox full of homemade similar screws.  I use them to line up assemblies as well as gaskets.  Particularly helpful on oil pans and gaskets.  Possibly Vellumoid was a gasket maker?
Edit - Vellumoid still in business from 1890's - http://www.vellumoid.com/about-vellumoid-gasket-and-sealing-solutions/

OK, so I can wrap my brain around this, you screw 4 of these into the bottom of the engine block with the tapered end pointing down, and that helps locate the oil pan as you lift it up into place?... That's brilliant.

What about an age to this set, 1950's or older?

That would be a good guess as I don't rightly know for sure a date range.

Email sent to Vellumoid Corp.  Let's see if they reply.

That was quick - apparently no one there is old enough to remember these.
"Thank you for your inquiry.
  Vellumoid, Inc. no longer has history on this kit. Our best guess is that this was available in the 1940s and 50s.
  I'm sorry we cannot be of more assistance.
  Regards,
  Anne LaMarche
  Vellumoid, Inc."

Great work guys !

Quote from: amecks on March 21, 2018, 07:09:21 AMI have a drawer in my toolbox full of homemade similar screws.  I use them to line up assemblies as well as gaskets.

Oh, yes; right helpful.  I used to have a couple of long bolts with the heads cut off and a screwdriver slot cut in the end, used when we were removing and installing the manual transmission in Volvo 140s.  Useful when removing because it supported the transmission until the input shaft was free of the clutch assembly (thus avoiding damage); vital when sliding it in.  The bottom of the transmission resembled the bottom of a boat: the engineers had laid out the shafts and then shrink-wrapped a casting around them, so the tranny was narrow for its height, and had no good surfaces on which to balance it.  I can't easily imagine doing that job any other way.

No longer own any Volvo 140s, so the bolts have wandered away.