Homemade Motor Arbor for Your Wind Generator or Other Needs




After Reading over numerous instructables about wind generators and failing to find a
motor arbor at any of my local hardware stores i decided to make my own.  I did find several online, however they were much more expensive than I expected, and the cheaper ones looked fairly flimsy.  While looking for the arbor, and getting mostly blank and confused looks from employees at Lowes, Home Depot, Harbor Freight, and several smaller auto repair and supply shops I noticed a Rod Coupling Nut of the correct diameter for my motor shaft (5/8") and the plan came together.  This is how I constructed my motor arbor for a 5/8" motor shaft.  These plans can be adapted for any sized motor.

Great Instructables for building a wind generator:

Step 1: Aquire Materials

To build the Motor Arbor for the 5/8" shaft I visited Home Depot and purchased the following materials:

1 - 5/8" x 2ft threaded rod ($4.38)
2 - 1/4" x 3/4" hex bolts (for set screws) ($0.10 each)
1 - 5/8" Hex Nut ($0.33)
2 - 5.8" Cut Washers ($.31 each)
1 - 5/8" - 11 X 2-1/8" Rod Coupling Nut  ($1.24)
1 - package of JB Weld ($4.97)

Grand Parts Total = ($11.74)

note: the JB weld and threaded rod can be used for multiple Arbors and numerous other applications so the real cost per arbor is approximately $3.10 USD

note: I used JB Weld to secure the rod to the connector nut because i do not own a welder and wanted to try and keep cost down, the stuff will hold like the dickens.  If you have welding equipment, use that instead of the JB weld.

Step 2: Required Tools

The tools I used to construct the Arbor were minimal to save time and because I was building it off of my dining room table and couldn't really clamp anything down or bring heavier tools from my workshop, which I am renovating currently.

Power Drill with a 7/32" Rigid Drill Bit rated for drilling metal (these bits are great, they will blast right through almost and sheet metal or angle iron i have used them on)

Angle Grinder with a metal cutoff wheel (any other tool that can cut metal will work, it is just used to cut a length off of the threaded rod and trimming the 1/4" hex nuts to size)

Vise Grips large enough to grip the 5/8" Connector nut
note: It is safer to secure the parts in a table vise when cutting and drilling them

1/4" x 20 tap (used to thread the set screw holes)

Step 3: Cut Threaded Rod to Size for Your Arbor

The first thing you want to do is to cut a length off of the threaded rod to the length you want.

I allowed 1 inch of the rod to thread into the connector nut, and left about an inch and an inch and a half extend out of the nut so I cut my length to 2.5"

Use you grinder to cut the rod, making sure to leave a clean end on both sides of the length so you can still thread a nut onto them.

Sorry i don't have an image of the project at this step.

Step 4: Use JB Weld to Join the Rod Connector Nut to the Threaded Rod

At this point you should have a length of threaded rod that is approximately 2.5 inches in length depending on your required application of the finished arbor.

Mix up equal parts of JB weld steel and hardener on a disposable surface, like yesterday's newspaper or piece of cardboard.

Measure the motor shaft and make sure you leave enough space in the connector nut to give a stable connection when it is placed over the shaft of the motor

I applied a liberal coat of the mixed epoxy on about 1 inch of one of the ends of the rod, making sure to get it in between the threads.

I also pressed a small amount into the first threads of the coupler nut on only one side, and then threaded the rod into the nut allowing the excess JB Weld to collect on the head of the nut until it was inserted approximately 1 inch into the nut.

Clean the excess epoxy off of the connection of the nut and rod, but leave a little to give a good bond.

Leave the rod and nut sit overnight to allow the epoxy to cure.

Alternatively, if you have access to welding equipment, use that instead of the JB weld.

Step 5: Drill and Tap Holes for the Set Screws

Once the JB Weld has hardened it is time to drill and tap the holes for the set screws.
Because I was using 1/4" hex bolts for the set screws I drilled the holes slightly smaller using a 7/32" bit to give a snug fit.

I drilled the holes far enough apart to allow the heads to still turn when tightening or loosening them once they are in the nut.

Drill the holes with your drill, holding the nut tightly with the vise grips on the opposite end of the connector nut as the threaded rod is placed so the openings are over where the motor shaft will sit.

After you drill both holes, making sure to bore you holes perpendicular to the nut, use a 1/4" x 20 tap to thread the holes for the set screws, making sure to add oil to the holes while turning the tap tightly into the holes.


Step 6: Test Your Set Screws

At this point you should make sure your set screws will fit snugly into the holes you have created for them. 

I did not like how far they extended from the connector so I trimmed them down to about half of their original length so they did not stick out so far when tightened to the shaft.

Hold the nut by the head with vise grips tightly and use your grinder to trim them down to the size you want, make sure to cut them cleanly and make sure they will still thread into the holes.

note: you don't have to trim the 1/4" hex bolts, I just did it as a preference

Step 7: Add Washers and 5/8" Hex Nut

Once you have the set screws the way you want them place the washers and the hex nut on the rod assembly as shown.

At this point the motor arbor is essentially completed, all that is left is to place it on your motor.

Step 8: Finished Homemade Motor Arbor

At this point all that is left is to place the arbor onto the motor shaft as far as it will go, and tighten the set screws with a wrench or pliers to a good solid fit between the motor and arbor.

When placing the arbor on the shaft of the motor i have found it best to hold the motor shaft so i can not rotate and twist the arbor on the shaft letting the threads in the connector bolt pull itself tightly onto the shaft, then to tighten the set screws.

And there you go, a homemade motor arbor that is more solid than anything I have seen online for the cost required to construct it.



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    14 Discussions


    2 years ago

    I have the reverse need. A motor with a 1/2" shaft and a disc with a 5/8" hole.

    Any ideas on how to accomplish this?

    Phil B

    9 years ago on Introduction

    This is a clever use of available materials.  It would seem the internal diameter of the coupler is less than 5/8 inch while the shaft is 5/8 inch in diameter.  Did you have to smooth the threads away on the end of the coupler where it slides over the shaft?

    3 replies
    CandromaPhil B

    Reply 9 years ago on Introduction

    When i originally measured the shaft it was about 1 14/16 inches in circumference so the true diameter is  just shy of 5/8" so the coupler slid over the shaft without much fuss, just a little twisting to get it the last bit.  If the shaft were any larger the inside of the coupler would have to be smoothed out on the inside.  I have done this before with nuts using a equivalent size drill bits (but it kind of chews up my bits), or a small drimel grinding drum. I hope this helps


    5 years ago on Step 8

    That's a cool idea thanks for the post ,I have an old treadmill motor that didn,t have an arbor .thanks to your idea I will replace my old ceiling fan generator with the new one.


    5 years ago on Step 8

    Looks awesome, Am I correct in believing that the actual shaft from the motor has no holes in it?


    7 years ago on Introduction

    THANK YOU. I'm trying to couple a motor tube shaft to a an acrylic sheet, and unbelievable difficulty in the arbor department! you'd think theyd have arbors around, but NO.


    7 years ago on Introduction

    That is EXACTLY what I needed for making a sharpener for engraving. Thank you so much!


    7 years ago on Introduction

    Thanks so much for this fix. I used your idea and fixed my off grid 175 watt DIY wind turbine off ebay. The helpful and friendly ebay seller originally wanted $15.00 for a custom milled arbor. Seeing that a new hub, blade and arbor (from the same ebay seller) was $44.00, I didn't see it was worth it. So, I decided to go with this method. The only setback was, I left my tap and die kit at home. I then lined the hole up in the shaft with the rod coupler. I drilled a hole through the 3/8" rod coupler and I used a stainless steel screw to secure the hub and shaft.
    It works great and saved a few bucks.
    Thanks for the great idea!

    sam D

    7 years ago on Introduction

    Hey this is great. I have come up with an open format for making the main shaft of a turbine, but hte idea of the thread connector at the end is a very handy one. I'm gonna give it a try. Cheers from australia.


    9 years ago on Introduction

    neatly done ! This will probably work for connecting a prop shaft to a small engine  as well, the only point that confused me though was why did you hold the nuts in the vicegrips while you cut the bolts?

    1 reply

    Reply 9 years ago on Introduction

    thanks,  the visegrips were just to save time and use fewer tools, it's probably safer to place the bolts and nuts in a vise when cutting and drilling