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BigBoy1
03-05-2014, 07:59 AM
My new band saw has a cheap plastic 2" dia. knob for adjusting the blade tension. The knob is very hard to grip and is located so close to the band saw cover, it is very hard to turn it without your fingers getting caught between the knob and cover.

I want to replace that plastic knob with a steel nut piece which will screw onto the shaft of the tension rod and have a hex head on the other end for wrench attachment. That should make adjustment a whole lot easier.

By question concerns attaching the steel nut to the rod. There is a roll pin hole in the end of the rod with screw threads which locked the plastic knob to the shaft. My question is how do I accurately locate the hole on the steel nut so when it is drilled through the nut , it will "match-up" with the hole in the shaft when the nut is screwed tightly on the end of the threaded shaft?

Appreciate ideas. Thanks.

Doozer
03-05-2014, 08:03 AM
Use a castle nut.

-Doozer

winchman
03-05-2014, 08:19 AM
You know the orientation of the hole. Assemble the nut and the knob, and mark the flat where the hole is located. Drill an oversized hole in one flat, reassemble the parts, and match drill through the hole in the shaft to get the correctly sized hole in the other flat.

Doozer's suggestion is MUCH better, though.

sawlog
03-05-2014, 08:26 AM
Is the knob pressed on or threaded? If you can get the knob off then you can measure the hole. I would just try to find a bolt or all thread rod to replace it and just make a new one.

Daveb
03-05-2014, 08:53 AM
Fit drill chuck to milling machine, fit drill that's a snug fit in the hole, put drill through hole in spindle, lower quill and grip spindle in small vise (threaded bit clear of jaws), clamp vise to table, withdraw quill, fit nut, drill hole. Can also be done on lathe with vertical slide, also on drill press if you have an extra hand.
Dave

vpt
03-05-2014, 08:55 AM
How to Locate a Hidden Hole?



Turn the light on. :D

Rosco-P
03-05-2014, 11:04 AM
Make a new knob and tension rod.

Daveb
03-05-2014, 12:53 PM
Turn the light on. :D

That takes me back a bit!

Rich Carlstedt
03-05-2014, 01:37 PM
[QUOTE=BigBoy1;907855].......I want to replace that plastic knob with a steel nut piece which will screw onto the shaft of the tension rod and have a hex head on the other end for wrench attachment. That should make adjustment a whole lot easier.
............................ My question is how do I accurately locate the hole on the steel nut so when it is drilled through the nut [QUOTE]

I have found that it is easier to just extend the shaft above the wheel guard and use the handle ...no wrench required and easy access
To match the hole , first spin on a dummy nut and bring it below the hole for whatever distance you want.
Note the axial location of the hole ..Say it is directly across your line of sight (90 deg) and parallel to the guard .
Stick a short pin in to confirm and then remove
Spin down the desired repair nut and get one flat that is 90 degrees to the hole. Mark that flat with a magic marker AND its bottom edge
Run the dummy nut up against it and lock or hold it in place ( critical)
Remove the repair nut and measure the distance from the top of the dummy nut to the center of the cross hole.
Now use this distance to drill a new hole in the repair nut ..on the "flat" marked and at the same measured distance from the bottom.
Drill one side only and install to see if it lines up. Drill the rest of the nut then if possible, or remove and finish drill on a press

Rich

jmarkwolf
03-05-2014, 01:51 PM
Watching this thread with interest. I need to do something similar.

I need to relocate a pulley slightly, along a shaft, to seperate two belts that pass too close to eachother.

The pulley is on a water pump shaft. I want to drill a hole in the shank of a new aluminum pulley such that a 3/16" bolt will drop smoothly through the new pulley and the original shaft.

So far my best idea is similar to what winchman says: drill a hole through one side of the pulley shank in the carefully specified location, then align the holes in the pulley and the shaft, then drop a 3/16" center drill through these holes to match drill the other side of the pulley shank.

I'm thinking the shank of the center drill will keep the pulley and shaft pretty well aligned while completing the hole in the "far side" of the pulley shank.

macona
03-05-2014, 02:27 PM
Pretty much, you dont. Put the new knob on and drill a new hole 90 degrees from the first. I prefer to use taper pins.

BigBoy1
03-06-2014, 02:45 PM
I was able to use the suggestions posted here to locate the existing hole in the rod and drill through the new nut and existing hole to make a new "knob" for adjusting the blade tension on my band saw. I finished it last night.

I was going to machine a hex on the top of the piece but then thought I'd need to get a wrench each time I wanted to adjust the tension so I went with a captive sliding bar which would be there all of the time for turning of the adjusting rod.

http://i163.photobucket.com/albums/t308/i422twains/PICT0676_zps7d9b78f2.jpg (http://s163.photobucket.com/user/i422twains/media/PICT0676_zps7d9b78f2.jpg.html)

doctor demo
03-06-2014, 02:51 PM
You could leave the plastic Knob alone and make a new or modify an existing socket to fit the knob.

Steve

BigBoy1
03-06-2014, 03:40 PM
You could leave the plastic Knob alone and make a new or modify an existing socket to fit the knob.

Steve

The plastic knobs were three corner and if I made a socket, that would mean I would have to go and find the "special" socket and then find the socket wrench to do the adjustment. I think I came up the the better solution.

MrSleepy
03-06-2014, 04:34 PM
I prefer to use taper pins.

I have come to loathe taper pins...especially Okuma taper pins.

Every friggin knob or handle is held together with through taper pins , and they thought it was a good idea to mushroom both sides of em all.

Rob

Paul Alciatore
03-06-2014, 04:57 PM
0. If using a mill, lock the X and Y table movements and leave locked for all of the below.

1. Place threaded shaft, with hole loosely in drill press or mill vise. You may want to use aluminum jaw inserts to avoid messing up the threads.

2. Place a matching drill in the chuck.

3. With power OFF and the shaft still loose, run the drill down the hole in the shaft.

4. Tighten the vise on the shaft.

5. Clamp the vise to the table.

6. Put the nut on the shaft, in the position you want. A second, lock nut will be useful here to keep it from moving while doing the steps below.

7. Use an end cutting mill to create a small flat on the nut if it is not already square to the spindle.

8. Use a spotting drill to start/locate the hole.

9. Finally, use the correct size drill to drill through both sides of the nut. It should just pass through the existing hole in the shaft.

BigBoy1
03-07-2014, 12:16 PM
0. If using a mill, lock the X and Y table movements and leave locked for all of the below.

1. Place threaded shaft, with hole loosely in drill press or mill vise. You may want to use aluminum jaw inserts to avoid messing up the threads.

2. Place a matching drill in the chuck.

3. With power OFF and the shaft still loose, run the drill down the hole in the shaft.

4. Tighten the vise on the shaft.

5. Clamp the vise to the table.

6. Put the nut on the shaft, in the position you want. A second, lock nut will be useful here to keep it from moving while doing the steps below.

7. Use an end cutting mill to create a small flat on the nut if it is not already square to the spindle.

8. Use a spotting drill to start/locate the hole.

9. Finally, use the correct size drill to drill through both sides of the nut. It should just pass through the existing hole in the shaft.

That is just about exactly what I did to make the new piece. Great minds run in the same channel!

Rosco-P
03-07-2014, 12:48 PM
I was going to machine a hex on the top of the piece but then thought I'd need to get a wrench each time I wanted to adjust the tension so I went with a captive sliding bar which would be there all of the time for turning of the adjusting rod.


Get a wrench?? The saw uses Allen keys for various adjustments, blade rub blocks (or bearings), etc., doesn't it? Do you hunt up the proper size when you change blades, make an adjustment or do you keep spares at the saw? Same rule applies for the wrench for blade tension nut, Vee belt adjustment, etc., keep dedicated duplicates on a rack at the machine to save time hunting. Service wrenches or old black oxide combo wrenches from tag sales are perfect for this use.