How can I remove this cog?

[Mark Gibney]

How can I remove this cog from this planer?
I removed a bolt at the front, and two small grub screws from either side - the location will be obvious in the photos.
I tried screwing in the grub screws to see if that would push the cog off, but nothing.
Can't get it to budge.

500777 500778 500779 500780

Thanks in advance for any advice.
Mark

[Ralph Boumenot]

You might need a gear puller - it was probably press fitted.

[Jerry Bruette]

That looks a little like a Taper Lock bushing but it's missing the third threaded hole for removal. You could try tapping the gear with a block of wood and a hammer outside of the tapped holes. If the inner part is tapered it should release from the gear. If you're trying to change the belt couldn't you pull the smaller gear that drives the big gear?

If you google taper lock bushing you'll see what they normally look like.

[Mark Gibney]

Ralph, I don't want to use a gear puller because I fear I'll just crack the cog. It's quite wide.

Jerry, yes it does look like a tapered bushing, but as you say it doesn't have the third hole to loosen the fit.
Do you mean tapping from behind?
I'm taking the gearing apart in order to change all the bearing, so unfortunately it has to come off.

[Jerry Bruette]

Ralph, I don't want to use a gear puller because I fear I'll just crack the cog. It's quite wide.

Jerry, yes it does look like a tapered bushing, but as you say it doesn't have the third hole to loosen the fit.
Do you mean tapping from behind?
I'm taking the gearing apart in order to change all the bearing, so unfortunately it has to come off.

No, I would try to knock the gear towards the machine. It looks like the center hub of that gear has the bearing in it. Hard to tell but looking at third picture the shaft may not have a shoulder to locate the gear set. You would line up the hub with the bearing and small gear and then attach the big gear.

Do you have a machine manual, or at least a name and model number and then you could look up a machine manual.

Another thought I just had. What size are the threaded holes? Could they be used for threaded rod and a strong-back for pulling the gear?

[Tom M King]

I would wait for a machinist to chime in before attacking it. It's probably easy if the correct procedure is followed.

I'm curious to know what those outer two holes are for. They may be part of the process.

[Mark Gibney]

Jerry, you know way more about this than me!
Tom, luckily my neighbor is a machinist, but is working on site this week. I'll try to catch him early today before he leaves.
When I do get it off I'll let you know the procedure.

EDIT: I just ordered the manual, should be here in a week or so.

[Jerry Bruette]

Here's a quick sketch of the device I'm talking about. The threaded rods would be threaded into the two holes in the gear. The jacking bolt would push against the shaft. You'd have to put a bolt into the shaft to protect the threads.

If you have or can borrow a tap you can make this puller yourself. All you would need is a piece of steel that is fairly thick, 3/4" would do. Drill and tap a hole for the jacking bolt and drill two holes for the threaded rod to match the hole spacing. Or, if you have access to a welder drill an over size hole and weld a nut on for the jacking bolt. Just be sure to have the threaded rod holes equidistant from the center hole and the proper spacing so you are pulling in a straight line. I've made dozens of pullers like this while I was working.

500791

[Mark Gibney]

Thanks Jerry, I'll let you know how it goes.

[Bill Dufour]

This is an idler pulley right?
I would replace the two screws with longer ones and see if screwing them in presses the bearing off. Do they have something solid to bear against below? Do not try too hard and break the casting.
If nothing else take a good tension on them and leave it over night You might heat the hub up to under 200F while under tension.
I agree they may be for a slide hammer. Or use a hub puller. Metric, English or American threads?
If worst comes to worst pull the seal and bearing cage then remove the balls. then use a puller on the inner race.
Keep all the puled bearings until the project is done. A little grinding and drilling and they make good bearing installers.
Bill D

[John TenEyck]

It looks to me like the set screws lock the bearing in place so it can't rotate independently of the cog nor move fore/aft. I would bet a gear puller similar to what Jerry showed is the way to remove it. The outer rods would not go in the set screws hole, however. The question is, from which side do you pull it? If the center hole thread is only available from one side, then there's the answer.

John

[Lee Schierer]

I would not use anything until someone correctly identifies the proper way to remove the cog from the shaft. I agree that it appears to be a tapered shaft and that the set screws should be removed, but you definitely don't want to screw new bolts into those holes and then apply pressure without knowing if that is correct.

You can likely get qualified help at the Old Wood working machines forum.

[Mark Gibney]

My machinist buddy went into my shop and took it off this morning before I got there.
Turns out it was not a tapered shaft.
Here's a pic of the gear puller he used, one of the many fancy ones he owns.

500835 The right tool for the job.
Thank you all for your advice.

[Jerry Bruette]

Glad you have a friend close by that could help you out. Now on to the rest of it. Don't let "analysis paralysis" get you with the bearings.

[Mark Gibney]

For sure Jerry. I have found that if you step away from a project like this you lose momentum, and you can forget how the jigsaw goes together, no matter how many photographs and notes you make.

[John TenEyck]

Exactly as expected. Glad to hear it went smoothly.

John

[Lee Schierer]

Glad you got it off. Make sure your check with your machinist friend about the best way to get it back on.

[Bill Dufour]

My wife taught me lots of baggies to hold each set of stuff. I taught her listo lead to mark the bags.
Bil D

[Tom M King]

I have a bunch of white dishpans and cups from a dollar store in the mechanic shop for when I take something apart. Each step goes in a separate container.

[Kent A Bathurst]

The use of the word "cog" is relatively uncommon - I can't help myself - this has been running through my head since I read the thread. Apologies, but............


So, is it a Cogswell Cog? Or maybe a Spacely Space Sprocket?


I'll go away now.

[Bill Dufour]

Cogswell college in San Jose has changed their name to Silicon valley College.
Bill D

[Brian Runau]

I think it is an idler bushing. Gently Driving the set screws in may remove it. See brewer machine idler bushings.