# This Clausing 8520 followed my home



## jlchapman (Apr 27, 2017)

I finally have a milling machine.  I'm helping a lady at work selling the contents of her late Father's shop.  I ended up buying the Clausing 8520.  Its a little ruf around the edges, but I can fix that with time and money.  It came with a lot of tooling, big NBK vise, and a Phase II 8" Rotary table.  I paid $800 for everything.


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## jlchapman (Apr 27, 2017)

The first thing I want to fix is the pulley on the motor.  The motor was replaced and the pulley is not the original.  It only has one belt position.  The speeds seem awful fast in the lowest setting.  Where can I buy a new pulley that is a two step?  What sizes should they be?  My motor shaft is .625.

The other thing driving me nuts is the belt adjustment knob up on top.  When the mill is on it shakes like crazy and makes a bunch of noise.  Looks like the knob has seen better days,  maybe bush it?

Terrywerm - I saw your post about the brake cam and handle.  I checked mine has the brake.  That is the next project to be completed.  Thanks for posting the pdf and the post showing how you did it.


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## woodchucker (Apr 27, 2017)

jlchapman said:


> I finally have a milling machine.  I'm helping a lady at work selling the contents of her late Father's shop.  I ended up buying the Clausing 8520.  Its a little ruf around the edges, but I can fix that with time and money.  It came with a lot of tooling, big NBK vise, and a Phase II 8" Rotary table.  I paid $800 for everything.
> View attachment 232260


Nice and with vise and rotary table you stole that thing..  Just kidding, I know she probably wanted you to have it after helping.

Good score.
Looks like just an on/off. is the motor single or 3 phase?
Mine had bearing issues in the pulley's  and the X you may want to check just to make sure everything is as good as it looks.
BTW YOU SUCK


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## jlchapman (Apr 27, 2017)

Thanks woochucker!  I like your Kennedy tool box you restored.

The motor is a single phase.  I also found the original switch, just dont know if its any good

Jerry


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## bob308 (Apr 28, 2017)

on the middle pulley check the bearings. mine were bad and made a terrible noise. they are cheap at the auto parts store.i would look for a smaller vise.  I have a 4" b&s on mine picked it up at a gun show.


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## jlchapman (Apr 29, 2017)

Well I fixed the belt knob that was bouncing around making noise.  Only to discover as bob308 and woochucker suggested to check the bearings.  The top bearing(below belt knob) was locked up.  Of course this wallowed out the aluminum pulley at least to 33mm( the outside of the bearing is 32mm).  Any suggestions how to fix the pulley?  I have the top and bottom bearings coming.  There is lots of material around the top bearing, can that be bored out and put some type of spacer between the pulley and bearing?  The shaft is fine.  Any other suggestions or ideas how to fix it?  Thanks!


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## woodchucker (Apr 29, 2017)

jlchapman said:


> Well I fixed the belt knob that was bouncing around making noise.  Only to discover as bob308 and woochucker suggested to check the bearings.  The top bearing(below belt knob) was locked up.  Of course this wallowed out the aluminum pulley at least to 33mm( the outside of the bearing is 32mm).  Any suggestions how to fix the pulley?  I have the top and bottom bearings coming.  There is lots of material around the top bearing, can that be bored out and put some type of spacer between the pulley and bearing?  The shaft is fine.  Any other suggestions or ideas how to fix it?  Thanks!



Depending on how damaged the race is, I tried to fit in a feeler gauge, but it didn't work out. So I kept cutting , made it larger, filled it with an aluminum plug, perm loctite and press fit in, then recut a new bore for a tight fit.
If yours is slightly wallowed, you may be able to dimple the inside of the race with a punch, create enough of them to hold it tight. BTW I used C2 replacement bearings. I think that the spec is wrong. I think that is why they are having a tough time. I think CN or C3 would be better. This is not a critical area, like the tables which definitely would require c2 bearings.  C2 has less clearance than normal, and c3 more.. Since they are spinning at speed, I think c3 would be better.


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## jlchapman (Apr 29, 2017)

Its wallowed beyond the dimple the inside of the race.  I'm just a beginner when it comes to machining.   This may be beyond my skill set.   I'm assuming you bored out the bearing race using your lathe.  What material for your aluminum Plug?  When making a press fit in aluminum what kind of tolerances due I need?  I have Perm Loctite 242, is there a different loctite for aluminum?  If you would please, give very detailed steps of the process.  Then I would have to decide whether to take this on or not.  The last thing I want to do is ruin a pulley that is almost impossible to get.

I have a Central Machinery 12 x 36 lathe and a South Bend 9 model A(going through a rebuild).  I have the tooling required for boring, outside micrometers, inside telescoping gages.  Dake arbor press.  I'll have to order some larger aluminum for the plug and try some of what I need to do on scrap aluminum before machining on the pulley.

Thanks,

Jerry


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## wa5cab (Apr 29, 2017)

Jerry,

I don't recall the part number and it may not still be what I can't recall anyway.  But there is a Loctite product that used to be called something like "Bearing & Bushing"  I think that it was green.

Bore the pulley out about 1/4" to 1/2" on the diameter (assuming that there is enough "meat" in the casting to do that).  So that the sleeve wall thickness when finished will be at least 1/8".  If the pulley is keyed, the plug wall thickness should be greater than the depth of the key slot

For the interference fit, I don't know what the shaft diameter is nor what the hole diameter will be after boring.  But probably something between 0.0002" and 0.0010" interference.  Machinery's Handbook has a whole chapter devoted to Fits.  I would also suggest cutting the ID of the plug under size and making a slip fit driver to do the assembly with.  Finish bore the repaired pulley after the Loctite has cured.  Then broach the new keyway if it has one.


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## jlchapman (Apr 29, 2017)

I chucked the pulley up in my lathe.  Used the dial indicator and got the runout to .005, the best I could get it.  I bored out the bad race by 2mm, its now 34mm, it used to be 32mm.  I didn't have aluminum that large so I used some 12L14 steel and made a sleeve.  The sleeve is 32mm id and 34mm od.  Everything seems to be good.  I attached some pictures.  Why could'nt I use a steel sleeve instead of aluminum?  Now I have to wait for bearings.  The bottom bearing is on its last leg also.  I noticed the race for the bottom bearings is loose, I could dimple that race to tighten it up.  The red highlighted part in the pulley, is that from the factory that way?

Thanks,

Jerry


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## Terrywerm (Apr 29, 2017)

Nice find on that 8520, Jerry, and a nice repair too!

Your steel sleeve should be just fine. I repaired the rear hub on my 83 Honda Gold Wing the same way, using a steel sleeve, pressed in along with plain old red Loctite . I had to borrow the use of a friend's 24" lathe to turn the bearing recess, but it worked just fine. As previously mentioned, I pressed in the sleeve, then turned the bore of the sleeve to the final dimension. After that the wheels got new bearings every time they got new tires. Bearings were cheap compared to wheel hubs.


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## JPigg55 (Apr 29, 2017)

When I contacted Clausing about parts for mine, they said they have some. You can try contacting them.
Here's a helpful link: http://www.wentztech.com/metalworking/equipment/clausing-8520-mill/
I have a lot of other info on the 8520 as well as some spare parts.
You can send me a PM of what you need/looking for and I'll see if I have it.


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## wa5cab (May 1, 2017)

The reason that I would have used 6061T6 Aluminum instead of steel for the bore sleeve is that steel and aluminum have different thermal coefficients of expansion.  But the steel sleeve will probably be OK.


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## Silverbullet (May 1, 2017)

Nice deal , very good price. The speeds are usually to fast on most small mills , something I've never understood. The mill looks to be in great shape good luck with it. Your pulley repair will hold longer then the bearings I'd bet. If it were three phase a VFD  would help with speeds, reverse , easier taping and more.


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## bob308 (May 1, 2017)

if you have a 1725 rp motor your speeds will be fine.  I made a part like was on the early 8520's where you loosen th draw bar and keep turning and it hits a stop and pushes the collect out of  the spindle rather then banging on  the draw bar.


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## jlchapman (May 6, 2017)

My 8520 has the hum of industry now.  I made another spacer out of aluminum, not because I needed to, I just wanted to play on the lathe.  I used perm loctite and pressed the spacer in.  Installed the bearing.  On the other bearing I dimpled the race and installed the bearing.  I also replaced the 2 bearings in the other pulley.  The mill sounds really good!

What is the purpose of the the 2 plugs, with spring and set screw in the plate above the front pulley?  Mine only had the 2 set screws, no springs or plugs.


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## woodchucker (May 6, 2017)

I assume you are talking the plug and spring in the black piece with 2 pins and 2 bolts, and a spline .
The spring and plug (nylon or delrin) are to create some friction to the spindle, probably to prevent knocking, and also to prevent if from dropping.
I have mine tightened pretty good and it still drops... so it's not working that good for that.


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## jlchapman (May 6, 2017)

Woochucker, that is what I'm talking about.  Thats what I was thinking, just taking up the slack.  Worth worrying about?  When first starting to rotate the plate/pulley will move I'm guessing 1/16 - 1/8" before the spindle moves. So you hear that noise on start up.


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