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Bosch GTS1031 - motor taken apart - armature help

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Forum topic by coolmint posted 07-11-2020 07:46 PM 484 views 0 times favorited 12 replies Add to Favorites Watch
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coolmint

7 posts in 33 days


07-11-2020 07:46 PM

Hello all, first post. I recently got a Bosch gts1031 used for only $70 (stand included). I wanted to check the bearings on the armature. I am having a heck of a time getting the armature out. Any advice? Just keep tugging?


12 replies so far

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MrUnix

8164 posts in 3009 days


#1 posted 07-11-2020 10:28 PM

From the pictures of the armature online, it has a twisted spline end on it (same as most Universal screamer motors), so you need to pull and twist counter clockwise at the same time to remove. You may want to somehow secure the output shaft to keep the gears from moving while you twist.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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farmfromkansas

210 posts in 424 days


#2 posted 07-12-2020 02:14 PM

You could call the Bosch service center.

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coolmint

7 posts in 33 days


#3 posted 07-12-2020 05:54 PM

Thank you Brad, going to try to pull it today. Wish I had a vise but will have to use pliers to secure the output shaft.

I will call the service center, I did cross post to Bosch : https://www.bosch-professional.com/gb/en/community/category/bosch-gts1031-table-saw-pulling-out-the-armature/15069417-t#/main

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coolmint

7 posts in 33 days


#4 posted 07-14-2020 10:37 PM

I was finally able to pull it out! The threading is reversed, I had to pull and rotate clockwise.

The bearing should be free I think? There was some sawdust around it, and the bearing didn’t spin much, unlike the bearing at the other end by the commutator. Here is a full-res pic: https://i.imgur.com/xRHlxtm.jpg

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farmfromkansas

210 posts in 424 days


#5 posted 07-15-2020 12:53 PM

So if the bearing is stiff, how hard is it to remove it? May need a bearing puller. But with a new bearing you should have a good working machine.

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coolmint

7 posts in 33 days


#6 posted 07-15-2020 07:57 PM

Thankfully I anticipated and bought a bearing puller tool. I’m considering cleaning out the black grease and putting in some molbydenum sulfide grease.

I have a tube of yamalube molybdenum sulfide grease,
and a tube of yamalube marine grease
and also a can of this

The molybdenum for the gear?

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MrUnix

8164 posts in 3009 days


#7 posted 07-15-2020 09:30 PM

You don’t need a puller, but it does help. However, for the bearing shown, you may not be able to get the fingers under it due to tight clearance with the fan. Usually for those, a bearing splitter is used. But an easy way to do it without either is to hold the bearing secure in a vice and tap the shaft down and out with a dead blow or wooden mallet.

As for the grease – I just use whatever wheel bearing grease I happen to have on the shelf at the time.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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coolmint

7 posts in 33 days


#8 posted 07-15-2020 10:29 PM

Thanks Brad, gonna makeshift a vise and I do have a dead blow hammer.

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coolmint

7 posts in 33 days


#9 posted 07-19-2020 09:16 PM

Question for anyone, the replacement bearings I purchased, OEM Bosch, are both significantly smaller in size.
Will changing to smaller outer diameter bearings impact usage in anyway?

The original one has a pretty tight tolerance, I’m still trying to press it in.

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MrUnix

8164 posts in 3009 days


#10 posted 07-19-2020 11:11 PM

What do you mean smaller in size? They should be identical. Take measurements of the old bearings (O.D., Bore, and width), and compare to the new bearings. Note: most all bearings are measuerd in metric – so measure in mm, not inches. Also – check the numbers stamped on the side of the old bearings to make sure they match with the replacement ones you have – suffix may be slightly different, but base number should be the same. If the bearings are different, it certainly won’t be the first time I’ve seen the parts diagram disagree with what is there… and one reason I always recommend pulling the old bearings first so you can verify what you got and what to order.

Cheers,
Brad

PS: There is no such thing as an “OEM” bearing ! Bosch didn’t make ‘em… some other company made them, and then they were slapped in a Bosch branded box/bag so they could charge you a few extra bucks ;)

-- Brad in FL - In Dog I trust... everything else is questionable

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coolmint

7 posts in 33 days


#11 posted 07-19-2020 11:44 PM

I think you hit it on the head, parts did not match the diagram I guess. Without even measuring the OD its visible enough without a needing a closer look to see the one I received is significantly smaller.

View bigblockyeti's profile

bigblockyeti

6646 posts in 2530 days


#12 posted 07-20-2020 12:10 AM

Pro tip – for removing a spindle or armature from a gear case, armatures will over 99% of the time have the helix cut to pull the shaft toward the housing, the gear end bearing will be larger or rarely the same size than the opposite end for handling the radial load of two gears trying to separate. That larger size also better handles the axial load induced by the helix angle of helical cut gears.

-- "Lack of effort will result in failure with amazing predictability" - Me

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