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  1. #1
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    Convection Oven Blower Motor

    Just sharing here...

    After reading similar aggravations when removing a fan or blower wheel from a motor on HVAC equipment, I thought I'd share a tactic I've used on several occasions when a motor in a convection oven must be replaced, yet the blower wheel won't budge.

    I generally order a new wheel anyway when ordering a replacement motor. The oven's heat takes a heavy toll on those wheels. They're often corroded and, when adding to tht the baked-on foodstuff the the wheel gathers in its years of round-about service at 350, well...it's definitely out-of-balance. So, it's best to replace the wheel along with that new motor.

    For the wheels that refuse to pull off, the motor shaft must be cut. So do you get at the shaft to cut it?

    Well, do you have a hole saw kit? The correct answer should be yes.

    Pick the smallest one that will fit around the hub of that wheel. Then, remove the guide bit from the mandrel. The hub of the wheel will keep the blade somewhat centered. Secure an appropriate tool to the wheel to keep it from spinning, then load the hole saw to the mandrel and then that to your drill...and cut away.

    When the wheel is cut loose, you have free access with your reciprocating saw to cut the motor's shaft.
    Last edited by ECtofix; 12-10-2013 at 10:49 PM.


    "You never know what others don't know." -

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  2. #2
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    I like it ! Someday I may have to use that TIP. Thanks for sharing.

  3. #3
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    What about using a piece of wood or something as a jig, then drilling holes on the blower hub as close as possible to the shaft and splitting it open with chisels/screw drivers? It might be easier to drill than the shaft.

    You could also drill at a 45 degree angle through a jig, or through the bearings of something like a roller skate wheel to hold the drill bit in place and drill right through the shaft.

  4. #4
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    I've fought a few of these used grinders, heat and pullers when I switched from B-tank to Oxy I cut them. Never tried this but next time I sure will Thanks

  5. #5
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    Nice tip with the hole saw, I'll be sure to pick one up.

    I've always used a good screwdriver and hammer and just punched the fan's sheetmetal off of the hub, to the back straight in. Takes a minute. Then grabbed the die grinder to chop the shaft off.

    Thank gawd for die grinders, dremels, and large hammers.

    Hey- what's the deal I see with the new "Gold" oxide (that's what it says) drill bits I see in Lowes, by several different manufacturers? Any better than the normal colbalt bits I usually buy? What's the best for stainless steel work, not counting cost, just the best drill bit type?

  6. #6
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    Thread Starter
    Quote Originally Posted by ICanHas View Post
    What about using a piece of wood or something as a jig, then drilling holes on the blower hub as close as possible to the shaft and splitting it open with chisels/screw drivers? It might be easier to drill than the shaft.
    Perhaps I didn't describe the wheel parts correctly. When I said "hub" I was haphazardly referring the part in the middle with the set screws. However, from what I just read elsewhere, I guess the actual hub of the wheel more aptly describes the entire portion of the fan that spans from the center out to the vanes attached to it, thereby comprising the main structure of the centrifugal fan (blower wheel). So I guess I need another name for the round part in the center that has the set screws. I'll now call that the "shaft coupling."

    From here, I'll correct my previous post:

    Choose the smallest hole saw that will fit around that shaft coupling. Remove the hole saw's guide bit (since it's not needed here). I should also add that you should remove the coupling's set screws if they're going to be in the way. Then...cut through the thin wall of the hub (the back of the wheel) AROUND the periphery of the shaft coupling...until the bulk of the blower wheel is cut loose. After doing this, the only thing still left to remove is just that coupling (with some remnant jagged edges) that's still attached to the motor shaft.

    With the bulk of the wheel now out of your way and having far greater access, you can either cut the motor's shaft (behind the shaft coupling that's still attached) or you can cut through the coupling longitudinally so as to spread it out with a chisel & hammer.

    This method I described prevents you from having to do any drilling of the motor shaft altogether.

    Quote Originally Posted by Dcumpson View Post
    I've fought a few of these used grinders, heat and pullers when I switched from B-tank to Oxy I cut them. Never tried this but next time I sure will Thanks
    I can't even begin to describe the frustrations I've had doing the same. The worst I had was getting a wheel off a Middleby-Marshall oven as I lay inside of it. I learned this little trick since then.


    "You never know what others don't know." -

    If I can't laugh at myself...then I'll laugh at YOU! -

  7. #7
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    Cobalt bits are harder and they're used to drill hardened steel. If you mean Kobalt the brand Lowe's sells, that's just their house brand that they use for a lot of stuff.

    I'm not familiar with "gold oxide". The gold colored titanium nitride bits cut like normal HSS bits, but they hold their edge longer by 3 times or so.

  8. #8
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    Thread Starter
    Quote Originally Posted by BadBozo2315 View Post
    Hey- what's the deal I see with the new "Gold" oxide (that's what it says) drill bits I see in Lowes, by several different manufacturers? Any better than the normal colbalt bits I usually buy? What's the best for stainless steel work, not counting cost, just the best drill bit type?
    I haven't seen the gold oxide ones. But, I haven't been shopping in a while.

    A buddy of mine had just "one" carbide bit that he'd gotten from working at a plant. Said he's had it for years and never needed to sharpen it. I was having some issues drilling some stainless one day. He went to his truck and got that bit. It chewed through that stainless like a hot knife through butter.

    Last edited by ECtofix; 12-11-2013 at 10:01 PM.


    "You never know what others don't know." -

    If I can't laugh at myself...then I'll laugh at YOU! -

  9. #9
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    Yeah, they said gold on the packages. I got a staff guy over to quiz him, but he didn't have a clue.

    Take a peek at Lowes.com and search for gold drill bit. They come right up. On sale at a good price. Doesn't make any real quality claims though.

    Yeah, Cobalt, no Kobalt. I've found them to be the better buy for stainless drilling.

  10. #10
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    Sort of a dumb question.
    If the motor is toast, and the wheel is toast. Why do you feel the need to take them apart? Sure you can junk them, but wouldn't your time be better spent on something else?

  11. #11
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    Quote Originally Posted by ECtofix View Post
    I haven't seen the gold oxide ones. But, I haven't been shopping in a while.

    A buddy of mine had just "one" carbide bit that he'd gotten from working at a plant. Said he's had it for years and never needed to sharpen it. I was having some issues drilling some stainless one day. He went to his truck and got that bit. It chewed through that stainless like a hot knife through butter.

    Carbide bits are brittle. They work good on a drill press or a stationary machine, but they can snap very easily like a twig on a hand drill especially with smaller bits.

    Quote Originally Posted by lytning View Post
    Sort of a dumb question.
    If the motor is toast, and the wheel is toast. Why do you feel the need to take them apart? Sure you can junk them, but wouldn't your time be better spent on something else?
    Perhaps the mounting arrangement requires separating them to remove the motor?

  12. #12
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    Thread Starter
    Quote Originally Posted by lytning View Post
    Sort of a dumb question.
    If the motor is toast, and the wheel is toast. Why do you feel the need to take them apart? Sure you can junk them, but wouldn't your time be better spent on something else?
    Remember now that we're talking about a $8000-10000 convection oven. The blower wheel circulates air up to 550. The motor is obviously outside of the cooking cabinet to remain relatively cool. The motor's shaft juts into the rear insulated wall through a hole not much larger than the motor's shaft. The blower wheel is mounted onto the motor shaft inside the oven.

    To replace a failed motor, the blower wheel must come off so it can let that bad old motor leave. The 1" diameter hole that the motor shaft juts through in the oven's back wall is too small to squeeze the 14" diameter blower wheel through.

    The blower wheel - good or bad - must still be removed to replace the motor.


    "You never know what others don't know." -

    If I can't laugh at myself...then I'll laugh at YOU! -

  13. #13
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    Thanks for that info. I don't do any hot line work, and was wondering what all the trouble was.

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