Question about spinner back plates

[Doug Moon]

I should know this by now but I dont.

I received a new spinner recently and the crankshaft hole in the back plate is considerably smaller than my 5/16" crankshaft. 

How do you guys drill this hole out and keep it dead in the center?

Thanks

[john e. holliday]

I use what is called a Plumbers Tapered Reamer.   Use it on props also.   Available at Ace Hardware,  Lowes and Home  Depot.

[dankar]

10/4 on reamer and get good quality one. Go slow and hit from both side to get nice even cut.

[Ward Van Duzer]

Carbon props are hell on reamers! 

W.

[Douglas Ames]

Step Drill and a drill press.

[Derek Barry]

Blow torch.

[Allan Perret]

Mount wood platform on drill press table.
Drill 1/4" hole into wood.  Or whatever size matches exactly the hole in your backplate.
Remove bit and use shank to align backplate over the hole in wood.
Use 3 wood screws with washers around the perimeter to clamp backplate.
Without moving the table or wood platform, chuck up the 5/16" bit and drill out.

[Randy Powell]

I use a rotary table and my bench top mill. Use a dead center to line it up and drill. Or use a small end mill and just use the rotary table to dial the hole up to the require diameter..

[billbyles]

Blow torch.

I like that, Derek...precision tooling is great!  Your "Matrix" is very cool!

[Tim Wescott]

Mount wood platform on drill press table.
Drill 1/4" hole into wood.  Or whatever size matches exactly the hole in your backplate.
Remove bit and use shank to align backplate over the hole in wood.
Use 3 wood screws with washers around the perimeter to clamp backplate.
Without moving the table or wood platform, chuck up the 5/16" bit and drill out.

Or locate it with the hole and glue it down with CA.  When you're done, just whack it lightly sideways to break the joint (CA is brittle, and doesn't have much shear strength), then clean up any residue with CA solvent (A.K.A. nitromethane).

[RandySmith]

OR JUST USE A REAMER 

Randy

[Wayne J. Buran]

You are definately asking for trouble trying to enlarge a hole with a drill. Will always be an oversize condition or a ripped up hole. . For our application opening up a plastic spinner/bushing or a prop the taper reamer of any kind is the best.
Wayne

[Bob Reeves]

OR JUST USE A REAMER 

Randy

Yep! The Fox prop reamers work fine.. They have two, one metric and one American standard.

[Will Hinton]

What Randy and Bob said.

[Doug Moon]

OR JUST USE A REAMER 

Randy

A prop reamer?  Really?

[Mark Scarborough]

Doug,, probably good to clarify that,, cause I had a drill instructor that was REALLY good at the reaming part,( or was that screaming,, I think I am to scarred to recall accuratly) 
, but not so good I suspect at keeping a hole centered on a spinner backplate,,

[RandySmith]

A prop reamer?  Really?

Yes  really    I use a 310 reamer then open up a few thou with a taper reamer if needed, or you can use just a taper reamer , ream from the back side.
Or if you have none and need me I can ream a back plaTE  and  swap with you, be careful that you do not ding, scratch, or bend the edge if you use any  of the other suggestions
I have also use a FOX prop reamer, and you can resharpen  them when dull using a dremel tool

Randy

[Doug Moon]

Yes  really    I use a 310 reamer then open up a few thou with a taper reamer if needed, or you can use just a taper reamer , ream from the back side.
Or if you have none and need me I can ream a back plaTE  and  swap with you, be careful that you do not ding, scratch, or bend the edge if you use any  of the other suggestions
I have also use a FOX prop reamer, and you can resharpen  them when dull using a dremel tool

Randy

I think i need to sharpen it and it should be ok.  I will give it a go tonight and see.

[Bob Reeves]

A prop reamer?  Really?

Yep! Takes a little work but I've done it a bunch of times for my Saito's. Never figured out a way to sharpen them without changing the OD so I just buy a new one when it gets dull... or after one time on a carbon prop.

[RandySmith]

Yep! Takes a little work but I've done it a bunch of times for my Saito's. Never figured out a way to sharpen them without changing the OD so I just buy a new one when it gets dull... or after one time on a carbon prop.

Hi BOb

You do not sharpen the reamers from the side, you sharpen them from the inside edge, think of looking at the step on the inside of the + , if you sharpen from the outside it does not work well and you make the reamer smaller ID, sharpen the edge that the outside touches at 90 degrees. use one of the small grinder wheels
Grind the cutting flutes upwards on the reamer, not on the side making them smaller diameter, your cutting wheel stone..whatever will not touch the side of the reamer

Randy

[RandySmith]

Carbon props are rougher on reamers than al.  backplate are.

 

[Sonny Williams]

With reference to drilling our carbon fiber props, it is very difficult to drill one out and keep in on center without securing the prop and aligning the oversize drill. If the drill starts in off center the prop will be out of balance with the blades or off balance in the hub. An off balance prop is murder on bearings and especially ceramic bearings. There are any number of ways of securing the prop for drilling. I personally fabricated a jig on my drill press that I can secure any size or thickness prop. That way the new drill size will be perfectly aligned with the original shaft hole. Hub balance is just as important as blade balance in relation to life of an engine.  

[Randy Cuberly]

Step Drill and a drill press.

I agree with the comments that drills are probably the least succesful method at keeping a hole centered...however I have used the method mentioned above by Allen P. and although a little entailed it works very well.  Precision reamers of the type mentioned by Randy S. are probably the best but to really insure that they ream on center one whould use a series of sizes and not ream more than about .030 at a time (unless the part is securely mounted and and you can use a milling machine with a stiff quill.).  The best quick and dirty method is the one mentioned by Doug Ames...Step drills work very well if one is using common sizes such a .250 to .312 as in this case mentioned.  
I really don't like tapered reamers because it's very easy to get chatter and an out of round hole that invariably runs off center.  They are not so critical when used on props because props are easier to balance than a spinner.

Randy C.

[Dick Pacini]

An alternative would be a small lathe with a 3 jaw chuck to hold the backplate so you could preferably single point bore or ream the hole.  A reamer should follow the existing hole as long as the lead chamfers extend slightly below the opening.

[RandySmith]

With reference to drilling our carbon fiber props, it is very difficult to drill one out and keep in on center without securing the prop and aligning the oversize drill. If the drill starts in off center the prop will be out of balance with the blades or off balance in the hub. An off balance prop is murder on bearings and especially ceramic bearings. There are any number of ways of securing the prop for drilling. I personally fabricated a jig on my drill press that I can secure any size or thickness prop. That way the new drill size will be perfectly aligned with the original shaft hole. Hub balance is just as important as blade balance in relation to life of an engine.  

The problem with drill bits is that they themselves will wander as the * twist *  themselves along , does not matter how tight you hold the piece being drill, unless you use a step drill bit

Randy

[RandySmith]

When using a step reamer, do not use a power drill or drill press to turn it.

Randy

[Randy Cuberly]

Just worth a mention...it's possible to buy piloted drill bits in common sizes also.  I have a pretty good set that I bought for about $80.00.

Randy C.

[Bob Reeves]

Hi BOb

You do not sharpen the reamers from the side, you sharpen them from the inside edge, think of looking at the step on the inside of the + , if you sharpen from the outside it does not work well and you make the reamer smaller ID, sharpen the edge that the outside touches at 90 degrees. use one of the small grinder wheels
Grind the cutting flutes upwards on the reamer, not on the side making them smaller diameter, your cutting wheel stone..whatever will not touch the side of the reamer

Randy

Hi Randy,
I do understand, even removing material from the flat will reduce the OD due to the angle of the relief behind the cutting edge. Granted it's small but you are still reducing the diameter every time it's sharpened.

[Larry Fruits]

Purchase a piloted counterbore from McMaster Carr, Enco, KBC Tools, etc. They come with either an intregal pilot or an interchangeable pilot. $15 to $30 depending on style you buy. Use in a drill press. Opens the hole as well as a reamer and follows the existing hole precisely. As said before drill bits will leave flats and will wonder.

 Larry Fruits   

[Larry Fruits]

Forgot to mention that the piloted counterbore works great for enlarging the hole in props as well.

 Larry

[RandySmith]

Hi Randy,
I do understand, even removing material from the flat will reduce the OD due to the angle of the relief behind the cutting edge. Granted it's small but you are still reducing the diameter every time it's sharpened.

Hi Bob

NO that is not correct, I have sharpened my .310 and .312 reamers maybe 50 times they are still exact same diameter, I have sharpened my 4 and 2 step reamers many times the are exact same.
You DO NOT grind the outside diameter, you grind the cutting edge that runs 90 degrees to the inside of the outside diameter .
If you still do not see it I will try to post a picture

Regards
Randy

[Bill Little]

I always use a Fox Hand Reamer on backplates and all props.  Nary a problem.

Bill

[RandySmith]

When sharpening this reamer , look at the small steps that are at the edge of steps, these are inside and NOT the outside diameter, However these cutting flutes join the outside flutes at the 90 degree junction, grinding the steps at that point is the way you sharpen reamers like this and it will not change the diameter.

If you look carefully at the reamer you can clearly see where they were ground at the factory that made them on the inside corner of each step

Regards
Randy

[Wayne J. Buran]

Fox reamer, has no back taper so you wont loose size if you resharpen on the chamfer as a correct reamer would be and on each step. Concurrently the Fox reamers are circular ground on the  outside diameter therefore when you sharpen on the face you will not loose size. The Fox step reamer is no way near a precison step reamer which has backtaper on the lands and will loose it's size if ground on the chamfer as it should be. So use the Fox step reamer or invest in one if you are reaming glass props. Its a good tool for what we need. Once again no drills. Drills cut from the lips and will grab. Also all drills naturally cut oversize so the tolerance is kept to the low side on purpose.
Thanks
Wayne

[Brad Smith]

Ah just hogit out with your Dremel tool it will be fine.

[Doug Moon]

Found my reamer.  It has seen better days as it has tangled with many carbon props and it appears to have lost.   I am sure it can be saved with a little work.

I picked up a great planes prop reamer at the LHS.  It says standard on the package.  First step cruised right through the back plate.  Second step right through no problem.  Slide it onto the shaft and it was too big, not by much but enough to wiggle it around.  DAMN IT!  I didnt check it prior to going at it.  I should have but I didn't.  I take it up to the last step and then go at it just a tad with a dremel.  Next I locate a brass insert I have from one of my MPI Products spinners that takes the hole down to a 5/16".  I got it working, but now I have to keep with that little insert. 

Oh well, live and learn. 

My dull reamer would have been the right size....

[jim ivey]

doug. C clamp it to a piece of wood and then drill or ream it,either one will follow the existing hole.  NP    jim

[john e. holliday]

Isn't it great to have short peices of brass tubing to shim spinners and props.   I have over done it on the reamer myself.

[Bob Reeves]

Best way to hold anything round that you don't want to mess up is to drill or cut a hole in a piece of hard wood the OD of the part. Then take it to your band saw and cut a slot through the hole. Place the part in the hole and put the whole mess in a good vice. The slot will allow the vice to clamp the part in the wood and the wood won't mar the part.

[Brett Buck]

NO that is not correct, I have sharpened my .310 and .312 reamers maybe 50 times they are still exact same diameter, I have sharpened my 4 and 2 step reamers many times the are exact same.
You DO NOT grind the outside diameter, you grind the cutting edge that runs 90 degrees to the inside of the outside diameter .

  Right. I have done my at least a few times, and you sharpen the shoulder, and don't touch the outside diameter.

I was surprised that when I used my Fox reamer on a carbon prop, it looked like and worked like I was using my fingernail before I got through the first time. Then, I sharpened it, and it stayed sharp for quite a while.

    Brett

[RandySmith]

  Right. I have done my at least a few times, and you sharpen the shoulder, and don't touch the outside diameter.

I was surprised that when I used my Fox reamer on a carbon prop, it looked like and worked like I was using my fingernail before I got through the first time. Then, I sharpened it, and it stayed sharp for quite a while.

    Brett

I was surprised many years back how fast CF props  kill the reamers !,,seem like they dull them faster than metal does.

Randy

[Ward Van Duzer]

and the whole time he thought it was my fault!


Ward-O

[Brett Buck]

I was surprised many years back how fast CF props  kill the reamers !,,seem like they dull them faster than metal does.

    It seems to go forever on aluminum. It didn't even make it through the first carbon prop- I was reaming it out, mine got too dull about halfway through, then I had to use David's, which was also mostly dull by the time I finished.

    But even on carbon props, once I sharpened it the first time, I was surprised how long it lasted. I think the mechanism is that if you get it sharp enough, it had enough local pressure to crumble the epoxy and then break off the fibers as opposed to try to actually cut them.

    I also tried to heat-treat a Fox reamer, but it didn't seem to be the right grade of steel. I would think it would be relatively easy to make a reamer out of 5/16 drill rod, even perhaps with hand tools, then harden it, which should last forever.

      Brett

[RandySmith]

and the whole time he thought it was my fault!


Ward-O

It was always your fault  Ward-O       

R

[RandySmith]

    It seems to go forever on aluminum. It didn't even make it through the first carbon prop- I was reaming it out, mine got too dull about halfway through, then I had to use David's, which was also mostly dull by the time I finished.

    But even on carbon props, once I sharpened it the first time, I was surprised how long it lasted. I think the mechanism is that if you get it sharp enough, it had enough local pressure to crumble the epoxy and then break off the fibers as opposed to try to actually cut them.

    I also tried to heat-treat a Fox reamer, but it didn't seem to be the right grade of steel. I would think it would be relatively easy to make a reamer out of 5/16 drill rod, even perhaps with hand tools, then harden it, which should last forever.

      Brett

Yep you are correct  I make reamers out of  O1  tool steel, or drill  rod  then harden and then  heat treat them, they last for years and I use them a lot.
And it really is not hard to do. I have stepped prop reamers in inch and metric size that I have hardened but those come from Asia not FOX. I will see how the FOX reamers do if I try to harden them, if they don't get better when quenched in oil, They may have to be heated up in a Charcoal bath untill cherry red, the carbon should help the steel in the FOX parts.


Regards
Randy

[Darkstar1]

Hmmmm!
Does that mean I have to BBQ stakes with my prop reamers too.