Re: Gearbox bearing replacement
Hi Michael/Ralph
Michael, I understand your concern about the bearing spacing
and position but think it¡¯s probably not too much of an issue, as most things
can be adjusted.? The position of the
shafts in their bearings affects the clearance between the worm and brass gear
and the end position of the output shaft determines where the drive band-wheel
sits, so affects the tracking of the blade.
I¡¯ve never removed my gearbox input shaft but have had to
change the bearings on the output shaft.?
I removed them the same way Bill did.?
The bearings are a tighter fit in the casting than on the shaft, so I drew
the new ones into the heated casting with a bit of all-thread and thick washers,
so they were flush both sides, then tapped the shaft back through. I can¡¯t remember
which side I re-fitted the shaft from but think I might have mounted the brass
gear before doing so, as it would have been easier to pin the gear to the shaft
that way. Seem to recall the pin hole wasn¡¯t on centre, so the gear only fitted
one way. ?
The curve of the brass gear¡¯s teeth should be central over
the worm, when the boss of the brass gear just touches the bearing inner race.? This is because the drive band-wheel is located
in its proper position by a spacer (#11 in the diagram in the Clarke
Metalworker manual that¡¯s in the files section ) between the inner face of the
drive band-wheel¡¯s boss and the adjacent bearing inner race, when the inner
face of the brass gear is against the other bearing¡¯s inner race. If the brass
gear isn¡¯t against that inner bearing the output shaft could float axially through
the bearings and the drive band-wheel wouldn¡¯t be in the right position to
track the blade properly. ?
If your brass gear is not centralized over the worm in this
position, then the output shaft bearing at the inner face of the gearbox needs
to either be pressed in further, or you space the gear off the bearing with
shim washers. The length of spacer #11 can be changed to suit if needs be.
Actually, to get everything in the right position you need
to mount the gearbox input shaft first, as the axial position of
the worm, in the direction of the input shaft, needs to be aligned centrally
about the output shaft¡¯s centre first. Again, I think you are better to pull
the bearings into the casting first, rather than assemble the bearings on the
shaft and press the unit in. On my saw, both bearings on the input shaft are
flush with the edges of the casting as delivered from the factory. There are no
steps or lands to position the shaft, that I know of, it¡¯s just maintained in
position by friction of the shaft in the bearings.
The reason to fit the bearings to the casting first, is that
the area of contact between the bearing outer race and the casting is much
bigger than the contact area between the shaft and the inner race.? Even if the fit is the same on both sides of
the bearing, you need a lot more force the fit the bearings to the casting than
the shaft to the bearings.? If fitted as
a unit the bearings will slide on the shaft, especially as there are no lands
on the shaft to keep the bearings and seal in position, unless you put spacers
in between the bearing¡¯s and seal¡¯s outer races. Putting spacers in is probably
best engineering practice, but these saws were not made that way initially, and
the loads on the bearings are not high, so the bearings last ok after tapping
the shaft through.
Last of all remount the blade, tension it and then run the
saw.? The back of the blade should just
NOT touch the rim on the band-wheel (~0.020¡± (0.5mm) clearance is good).? Shift the band-wheel on its shaft to get this
clearance and either reduce or lengthen the #11 spacer to suit (5/8¡±ID ?plastic electrical conduit or washers makes good
spacer material).? Rgds - jv
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Re: Gearbox bearing replacement
"
out?the back with a brass drift"
At least now I have a direction, thanks.
Sure would be nice to see a video.
Ralph
On Thu, Apr 19, 2018 at 11:00 AM, 'W. Smith' wsmith1417@... [4x6bandsaw] <4x6bandsaw@...> wrote:
?
I have the Harbor Freight version... It's been many years since I did
this, so I hope myu memory is accurate. I pulled things apart to make a
new shaft for the bottom drive wheel - and when I did, my bearings
looked crappy so I replaced them too.
So, the brass gear was pinned to the drive shaft. I used a punch to
drive out the pin - it's a pita because of the angle, but was doable.
Then I pulled the brass gear, and drive shaft, removed the key from the
shaft and carefully drove the shaft out with a drift.
It's been so long that I've utterly forgotten how I removed the worm. I
do recall that my outer oil seal was crap, that the worm and its shaft
were one piece, and there was a spacer that held the space between the
bearings - but that's all I remember.
I probably I knocked the worm (bearings and all at the same time) out
the back with a brass drift - I wish I could recall.
Bill
On 4/19/2018 10:27 AM, Ralph Hulslander rhulslander@...
[4x6bandsaw] wrote:
> How to??
>
> How do I remove the gears (well worn gears)??
>
> Ralph
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Re: Gearbox bearing replacement
I have the Harbor Freight version... It's been many years since I did this, so I hope myu memory is accurate. I pulled things apart to make a new shaft for the bottom drive wheel - and when I did, my bearings looked crappy so I replaced them too.
So, the brass gear was pinned to the drive shaft. I used a punch to drive out the pin - it's a pita because of the angle, but was doable. Then I pulled the brass gear, and drive shaft, removed the key from the shaft and carefully drove the shaft out with a drift.
It's been so long that I've utterly forgotten how I removed the worm. I do recall that my outer oil seal was crap, that the worm and its shaft were one piece, and there was a spacer that held the space between the bearings - but that's all I remember.
I probably I knocked the worm (bearings and all at the same time) out the back with a brass drift - I wish I could recall.
Bill
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Show quoted text
On 4/19/2018 10:27 AM, Ralph Hulslander rhulslander@... [4x6bandsaw] wrote: How to??
How do I remove the gears (well worn gears)??
Ralph
|
Re: Gearbox bearing replacement
How to??
How do I remove the gears (well worn gears)??
Ralph
On Thu, Apr 19, 2018 at 9:58 AM, gerry waclawiak gerrywac@... [4x6bandsaw] <4x6bandsaw@...> wrote:
?
Hi and welcome to the group?
I'm rather surprised that you have had ?to replace bearings as they generally last well
A far more common problem with these is that the soft brass gear wears our very quickly and leaves you with a gearbox full of what appears like gold paint. The problem is due to the poor finish of the steel worm gear with sharp edges and burrs which turn
it into a quite effective cutting tool which quickly years the brass gear to shreds
Many people have also questioned the quality of the Chinese gearbox oil
Mine suffered from this and during ?replacement I followed the recommendations to hand work the steel worm to remove burrs and slightly round ?the edges and then to fill the box with a quality gear oil
I must admit I didn't really think about the position of the bearings and just pressed them flush to the housing.
The saw has run much quieter since and has lasted far longer than the first with the factory gear.
Gerry W?
Leeds UK?
Sent from my Samsung Galaxy smartphone.
-------- Original message --------
Date: 19/04/2018 10:52 (GMT+00:00)
Subject: [4x6bandsaw] Gearbox bearing replacement
?
Thank you for allowing me to join this group! ? This is my first post. ?
I own a Clark Metalworker 4x6 and have used it in my hobbies for many years.? The bearings in the gearbox have finally worn out and I¡¯ve removed both shafts and pressed the old bearings off, and have acquired new bearings and seals from McMaster. I¡¯ve
now pressed the new bearings; spacers and seals onto the shafts and am ready to press the assemblies back into the housing. ?
My question is what is the best procedure for pressing these assemblies into the housing while obtaining the correct spacing between the gears?? I¡¯m accustomed to pressing bearing races into a bore up against to shoulder that would ultimately determine
the final positioning of the assembled unit.? I regret not obtaining a micrometer measurement of the shaft positions in relation to the casting prior to disassembly. ??
Perhaps I¡¯m over thinking this?? Any advice would be appreciated. ?
Thank you. ?
|
Re: Gearbox bearing replacement
Hi and welcome to the group?
I'm rather surprised that you have had ?to replace bearings as they generally last well
A far more common problem with these is that the soft brass gear wears our very quickly and leaves you with a gearbox full of what appears like gold paint. The problem is due to the poor finish of the steel worm gear with sharp edges and burrs which turn
it into a quite effective cutting tool which quickly years the brass gear to shreds
Many people have also questioned the quality of the Chinese gearbox oil
Mine suffered from this and during ?replacement I followed the recommendations to hand work the steel worm to remove burrs and slightly round ?the edges and then to fill the box with a quality gear oil
I must admit I didn't really think about the position of the bearings and just pressed them flush to the housing.
The saw has run much quieter since and has lasted far longer than the first with the factory gear.
Gerry W?
Leeds UK?
Sent from my Samsung Galaxy smartphone.
toggle quoted message
Show quoted text
-------- Original message --------
From: "guilbault_michael@... [4x6bandsaw]" <4x6bandsaw@...>
Date: 19/04/2018 10:52 (GMT+00:00)
To: 4x6bandsaw@...
Subject: [4x6bandsaw] Gearbox bearing replacement
?
Thank you for allowing me to join this group! ? This is my first post. ?
I own a Clark Metalworker 4x6 and have used it in my hobbies for many years. ?The bearings in the gearbox have finally worn out and I¡¯ve removed both shafts and pressed the old bearings off, and have acquired new bearings and seals from McMaster. I¡¯ve
now pressed the new bearings; spacers and seals onto the shafts and am ready to press the assemblies back into the housing. ?
My question is what is the best procedure for pressing these assemblies into the housing while obtaining the correct spacing between the gears? ?I¡¯m accustomed to pressing bearing races into a bore up against to shoulder that would ultimately determine
the final positioning of the assembled unit. ?I regret not obtaining a micrometer measurement of the shaft positions in relation to the casting prior to disassembly. ??
Perhaps I¡¯m over thinking this? ?Any advice would be appreciated. ?
Thank you. ?
|
Gearbox bearing replacement
Thank you for allowing me to join this group! ? This is my first post. ?
I own a Clark Metalworker 4x6 and have used it in my hobbies for many years. ?The bearings in the gearbox have finally worn out and I¡¯ve removed both shafts and pressed the old bearings off, and have acquired new bearings and seals from McMaster. I¡¯ve now pressed the new bearings; spacers and seals onto the shafts and am ready to press the assemblies back into the housing. ?
My question is what is the best procedure for pressing these assemblies into the housing while obtaining the correct spacing between the gears? ?I¡¯m accustomed to pressing bearing races into a bore up against to shoulder that would ultimately determine the final positioning of the assembled unit. ?I regret not obtaining a micrometer measurement of the shaft positions in relation to the casting prior to disassembly. ??
Perhaps I¡¯m over thinking this? ?Any advice would be appreciated. ?
Thank you. ?
|
No base, just the sheet metal legs. I'm in NY, 11747 Zip Code.
|
Hi,
Where are you located? I would be interested in the saw base if not too far from me, im in San Diego.
J Estrada
|
Would anyone want a table and set of legs for a Harbor Freight 4 X 6 bandsaw? Never used, 3-4 years old. Free for the cost of shipping.
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Re: Broken Motor Mount - Need Help/Advice
If you have a Stick/Arc welder you can try this rod below to weld Cast Iron
Joe
https://www.praxairdirect.com/PXItemDisplay?storeId=10152&catalogId=10051&langId=-1&itemID=62313&categoryId=11681&top_category=11503&parent_category_rn=11676
NI-ROD? WELDING ELECTRODE NI 99X 3/32 1# - INCN99X-093-1TS
Ni-Rod welding electrode is used for
shielded-metal-arc welding of gray, ductile, and malleable cast irons.
It is also used for joints between cast irons and carbon steel or
low-alloy steel.. The electrode is particularly useful for thin sections
and for joints to be machined.
The electrodes provide excellent
operability for groove and fillet welding in the downhand position and
the smaller diameter electrodes are also suitable for all position
welding. ?Power supply: direct current, electrode positive, or
alternating current.
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Re: Broken Motor Mount - Need Help/Advice
I welded what I thought was cast iron with nickel rod many years ago using an ac welder. ?The rod was expensive but ran really well and held. ?Good luck what ever process you use or if you fabricate something.
On Fri, Mar 2, 2018 at 12:50 AM, K Mayer mayerk@... [4x6bandsaw] <4x6bandsaw@...> wrote:
?
> Posted by: "Bill Armstrong" bill_1955@... warmstrong1955
> Date: Thu Mar 1, 2018 9:28 am ((PST))
>
>Send a pic. I bet it would be easier, and stronger, to fabricate one.
>
>You need nickel rod to weld cast iron, and it does not weld like steel.
Not true. Cast iron can be gas welded using cast iron filler. Cast iron piston rings can be used as filler. High temperature flux is required.
https://www.youtube.com/watch?v=zyX7tdG84vk
https://www.youtube.com/watch?v=jUWMnrrf2q8
Ken
:-)
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Re: Broken Motor Mount - Need Help/Advice
I am not a welder, I fit the saying "A
lot of grinding and a little paint, makes me the welder that I
ain't"... However, having said that I broke the jaw on a five inch
vice. I ground out a good "V" Groove then took my Acetylene torch
and brazed that with a brass rod.? That weld lasted for years and
only broke when I was trying to bend a piece of metal.? I had
about a 24 inch piece of pipe as an extension to give me the extra
torque so I cannot really fault the welding even now as something
had to give.
There isn't that much pressure on a motor mount so I would be
willing to give it a try.
--
Harvey L. McRae
Kelowna, B.C.
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Re: Broken Motor Mount - Need Help/Advice
OK I've done repairs to cast iron on my bandsaw before... it may or may not be possible due to the size of the piece and the equipment you have available.? To weld it doesn't require special welder wire or rods but it may help.? What you need to do is to grind it so you have a bevel where it will be filled with weld and to heat up the cast iron pieces until they are orange.? Otherwise it will not weld properly and will get brittle.? If you have a forge you can heat it or a large torch it can be done.? Looks like you will have to clean it up afterwards with a grinder and drill or files.? So you have choices now.? Weld it and repair it, replace with new part from harbor freight if they have it or start from scratch and fabricate a plate. ? Good luck?
On Fri, Mar 2, 2018 at 12:02 AM, K Mayer mayerk@... [4x6bandsaw] <4x6bandsaw@...> wrote:
?
> Posted by: "K Mayer" mayerk@... kenmayer2001
> Date: Thu Mar 1, 2018 9:50 pm ((PST))
>
>> Posted by: "Bill Armstrong" bill_1955@... warmstrong1955
>> Date: Thu Mar 1, 2018 9:28 am ((PST))
>>
>>Send a pic. I bet it would be easier, and stronger, to fabricate one.
>>
>>You need nickel rod to weld cast iron, and it does not weld like steel.
>
>Not true. Cast iron can be gas welded using cast iron filler. Cast iron piston rings can be used as filler. High temperature flux is required.
>
>
>
Here's another:
Ken
:-)
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Re: Broken Motor Mount - Need Help/Advice
Posted by: "K Mayer" mayerk@... kenmayer2001
Date: Thu Mar 1, 2018 9:50 pm ((PST))
Posted by: "Bill Armstrong" bill_1955@... warmstrong1955
Date: Thu Mar 1, 2018 9:28 am ((PST))
Send a pic. I bet it would be easier, and stronger, to fabricate one.
You need nickel rod to weld cast iron, and it does not weld like steel. Not true. Cast iron can be gas welded using cast iron filler. Cast iron piston rings can be used as filler. High temperature flux is required.
Here's another: Ken :-)
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Re: Broken Motor Mount - Need Help/Advice
Posted by: "Bill Armstrong" bill_1955@... warmstrong1955
Date: Thu Mar 1, 2018 9:28 am ((PST))
Send a pic. I bet it would be easier, and stronger, to fabricate one.
You need nickel rod to weld cast iron, and it does not weld like steel. Not true. Cast iron can be gas welded using cast iron filler. Cast iron piston rings can be used as filler. High temperature flux is required. Ken :-)
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Re: Broken Motor Mount - Need Help/Advice
Thanks everyone. I will try that plate idea. I have the square tubing finished. Just need to tap the holes.
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Re: Broken Motor Mount - Need Help/Advice
Hi When making a new motor mount you might consider a different way of tensioning the belts too.? The std saw pulleys have a different belt length for each speed, which means you have to re-tension the belt at every speed change.? The std thumb screw is pain to use and not effective.? You'd be amazed at how much quieter/less vibration there is with a solid motor mount and decent tensioning device.? From the first picture you posted the mount I made would work well (just a plate bolted to the square bar) and the tensioning device is solid and v. quick to use.? Pictures of the mount and tensioning device are in the Photos section:?
Rgds -- jv ?
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Re: Broken Motor Mount - Need Help/Advice
Oh crap I overlooked that. I just ordered parts for mine from grizzly I hope they are the same as Harbor Frights saw.
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Re: Broken Motor Mount - Need Help/Advice
I think that the bigger problem is that the pivot lug is snapped off.
From: "pcservicedept@... [4x6bandsaw]" <4x6bandsaw@...>
To: 4x6bandsaw@...
Sent: Thursday, March 1, 2018 6:43 PM
Subject: [4x6bandsaw] Re: Broken Motor Mount - Need Help/Advice
?
would it be possible to drill another hole in the motor casting and move the bolt over??
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Re: Broken Motor Mount - Need Help/Advice
would it be possible to drill another hole in the motor casting and move the bolt over??
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gerry waclawiak
mrfixit82852