Making D Bit Reamers

S

shooter123456

Registered
Registered
Joined
Jan 20, 2016
Messages
602
I have been trying to make some reamers recently and I am having some trouble getting the geometry correct.

The most info I have been able to find just says to turn a rod to the right diameter, then cut it in half. I tried that and it didn't go very well the first time. I had trouble with it skipping around over the hole before it dug in and started cutting.

Then I tried adding some angles based on a video I saw where it worked well and that went ok, except I overshot it a little when cutting in half and it was about .005" undersized and when cutting, the hole had a poor finish and was oversized by a good bit.

Instead of making 5 more until I get closer, I figured I would ask and get some guidance first.

Ill add some pictures so you guys can see where I am.

I was working with a piece of O1 tool steel that I turned down to .2501", then stuck it in the spin index on the mill and cut it in half and cut a bit away at the back end. Then cut the angles. I hardened on the drill press while spinning using a propane torch and mapp gas and quenched in used motor oil. Then cleaned it up a bit and sharpened on a stone.

Any help would be great.

nxAp3Kg.jpg

QhlNcgv.jpg
 
Can you use a regular reamer to do the job? Need a slip fit, push fit, or press fit? I can send you a reamer if you want.
 
Billh50 said:
Can you use a regular reamer to do the job? Need a slip fit, push fit, or press fit? I can send you a reamer if you want.
Click to expand...
I could use a regular reamer for the job but I want to learn to make them. Fit really isn't all that critical in this case because the reamer is the project, not the tool standing in the way of finishing another one.

But I really appreciate the offer.
 
Oh ok. Never made a D reamer so can't help you there.
 
It looks to me like the bottom leading edge on the front of the reamer would be rubbing before the cutting edge can cut. Of course I have bad eyes
 
Try looking at “making reamers for the clockmaker”. And the ones that I’m thinking about are OK for reaming thin material, but don’t try it on a deep hole…Dave.
 
Ok. I'll attempt photos. Haven't put a photo on hear since the site switched platforms. Also my trusty old digital camera died so this is a first for my to use a phone camera to get an image on the computer.

I'll attempt to insert a pic and write the description under:
View media item 955463 drills. Bottom is a commercial gun drill. The carbide is chipped but you can see the shape. Middle one is a D-reamer I made. The cutting edge on the front extends past center. it's made from 5/16 0-1 and the shank is not relieved(mistake). The top one is .375 with a 22 cal pilot that was made to follow the bore in a 22 pistol barrel. It's 0-1 and has the shank relieved.

View media item 95547Side view of all 3. Of note is the relief under the cutting edge of the one in the middle. I made that reamer to finish the unreachable center portion of a 22 cal barrel that was to long for the purchased barrel lining drill to reach from both ends. It is 17 inch and the barrel lining drill is 14. It only needed to enlarge a couple of inches of barrel and it worked even though I did not relieve the shank.

View media item 95548Back side and you can see that the cutting edge is now at the top and that it leads all other surfaces. The top one is .375 with the remaining shank turned down to .360. I didn't relieve the underside of the cutting edge. It is more a drill than reamer.

View media item 95549This is the reamer I made to finish the .375 drilled hole to .380 for the liner. It's 12 1/2 inches long so will do most pistol barrels. More difficult to make than the others as you must start with larger stock and reduce to the size for the cutting edge and reduce the shaft even smaller. Made it on the mill with a spin index and made the mistake of not supporting the end so you can see the flute is wider at the end where it flexed away from the end mill Didn't seem to bother it much diameter was cut first of course. Not sure if any of this is helpful. Other than the commercial gun drill these are basically roughing tools as all they must do is make the hole large enough for the liner that gets either Loctite, solider, or fiberglassed in place.
Not sure what kind of hole or tolerance your working for but I have heard that a simple angled cut on round tool steel that is then hardened makes a nice finish as a reamer. I have yet to try that. I believe it needs to be close to hole size.
 
I'm left handed and that last reamer cuts backwards (counter clockwise) I'm gonna act like that was intentional!
 
You must log in or register to reply here.
Back
Top