Valve Guide drill bit source needed
 

I used to get them from Baum tools. Jerry Woods Had them for a while IIRC. Getting a batch made from a tooling outfit isn't cheap. Any idea who still stocks them?
Pilot end is 9mm to fit the guide bore.
Drill bit OD is 11.80mm/.464".
I'm down to my last one.

http://forums.pelicanparts.com/uploa...1608327882.JPG
http://forums.pelicanparts.com/uploa...1608327882.JPG

Could you make a few step drills using your metal lathe, a toolpost grinder (or even a Dremel mounted to the toolpost) and the correct-size drill bits (.464" O.D.)?

Nix

Apologies John- not much data out there. Using the Wayback Machine, I was able to find the old listing from the Baum Tools online catalog for May of 2005. Below is the main image clip. The pop-out was not available, but it references Tool #87 as well. Hopefully, this helps in the search...

Link: https://web.archive.org/web/20050507123638/http://tools.baumtools.com/index.jsp?menu=por&newIndex=3&index=11&make=por&mo del=&part_number=&primary_section=&secondary_secti on=&tool_use=

http://forums.pelicanparts.com/uploa...1608345941.jpg

Baum said they didn't have them, but I'll try calling with the number 86B.

Looks like a modified twist drill bit. A good machinist with a grinding attachment on a lathe and the proper sized collet could knock out a batch reasonably quickly. Mc Master will have the core bit.

I have done this. Takes time, fiddling, and knowledgeable use of a lathe with a tool post grinder then finished with a drimel, but is do-able for a DIYer.

Don't have a tool post grinder. Rather buy several. Already priced getting some made and it's out of hand. Must be some out there for sale.

John,

I will poke around as we would buy a bunch as well.

can you go to .492 OD?

https://www.cylinderheadsupply.com/dcmkwikway.html

item 7211 is sorta kinda close

all you're doing is drilling out the old guide and leaving a shoulder so you can pound it out?

maybe another

https://www.mcmaster.com/29525A56/

I don't have the stem diameter so I looked at my BMW motorcycle book and the airheads use 8mm stems.

John - I suspect there are many Seattle-area shops making custom machining / cutting tools for the local aerospace industry. I did a quick Google search and came up with this one:

Cutting Tool Control, Inc

Cutting Tool Control, Inc

Cutting Tool Control, Inc

I'm sure there are others. If you know somebody local in the machine-shop business, they may have a favorite tool grinding service they use.

Hey Jeff you may want to reach out to Modern Engineering on River Road, they may be able to help.

Cheers,

Andrew

Cutting tool control did the last batch, but new people in there now that are less than cooperative.
Swift tool wants $149 for one and $84 each for six. Gotta be a better deal.

If the OD is much larger, the remaining shell is thinner and I fear it could break from the driven part and remain in the bore. The size I have now works fine.

They were ready made and available several years ago, just for drilling out 911 guides, so there should be a source from the past that provided them.

Thanks!

Since this has the same layout as a drill piloted counter bore, what stops you from sharpening the current ones you have?

The drill point is pretty standard and the counter bore portion can be sharpened on a tool grinder. Same operation as tip sharpening an endmill.

the one I found on McMaster Carr has a big ID of .469 and a small ID of .313 (8 mm) and they want $59

this should work and I doubt you will beat the price

But I need a 9mm pilot. 8mm works for a 993. I have those.

Does your valve grinder index at 90 degrees? If so, I'd at least try buying a 15/32" drill bit and chucking it up in the valve grinder at 90 degrees and turn it down to 0.354". Obviously true up the stone first and go slow.

That can be done. It's the large OD cutting angle that's going to be difficult.

After cutting the 9mm shank in the valve grinder, cut the OD cutting angle at your desired angle using the side of the stone. Grind the relief by hand if it makes you feel better. Likely not needed on soft valve guides.