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Taft-Peirce No 1 Grinder Recondition

nobrakese28

Cast Iron
Joined
Feb 1, 2015
Location
Pico Rivera
I recently purchased a Taft-Peirce Number 1 surface grinder, the machine was stated to be in good shape (cleaned and ready to work) and was sent to me from Pennsylvania to Los Angeles. Somewhere along the way the machine was damaged and managed to work its way out of the crate which was likely built insufficient.

Upon inspection at the freight terminal I decided to reject the shipment because of the damage that was visible. After about 2-3 weeks I finally got my return (sent to wrong address) in full and got to keep the surface grinder ( dealer insisted).

Before scraping the grinder, I decided I would try and salvage anything useful, mostly the micro-adjust vernier dials, chuck, etc.

The obvious damage:

Ball-bearing spacers damaged and missing, most balls gone
Spindle motor housing was literally worn down from rubbing
Lots of deep scratches along the body
Control rod for table was bent
Broken oiler lines
Damaged wiring
Bent sheet metal covers

I decided to check if the spindle was bent, and was delighted to find it has less that .0001" run out, and powered up nice and quiet. The Y and Z axis moved freely, although it was obvious the Z-axis needed to be cleaned thoroughly.

I have decided to recondition the machine, and to be honest if the machine wasn't damaged in transit I would have been pretty upset in the condition of the machine, it was promised to be cleaned and ready to work, but it is full of grit and would have needed to come apart anyways.

The following photos will show the process of disassembly and some of the challenges I have faced so far, but it has mostly smooth. Taft-Peirce really likes Woodruff keys, and these little keys tend to get damaged or can lodge them selves into the bearings if you aren't careful when driving shafts out. Its best to use a gear puller on the hubs and gears.

Photos of machine when delivered. So far all of the ball tracks/ways don't have any lips or grooves that I can feel with my fingernail. No signs of brinnelling from the balls hitting/bouncing in the ways.

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When removing the handles, its best to remove the nut (you will need a 3/16 pin spanner), then tap the handle hub with a soft mallet till the hub walks off the shaft.

The x-axis can be a little tricky, and may be best to remove with the saddle. It will prevent maneuvering of the shaft/gear assembly to free it.

The Y-axis (head up and down), is the easiest to remove. Pull the hub/handle, then remove the three screws, the entire assembly will come out.

The Z-axis, same procedure as Y-axis, but I decided to un-thread the drive screw from the brass-nut.

The saddle lifts off, but you will need to remove the ball bearing ways in the center, the outer ways are roller bearing.

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Last night I pulled the spindle/tilt assembly. I used an engine hoist to help off load the weight and prevent and disasters, make sure you have all 12-bolts removed, there are two that are hidden near the front of the spindle nose, I used lots of oil to make it slide up.

I had a hard time removing the tilt-mechanism. When driving out the shaft, the keyway for the worm gear assembly was caught in the spacer washer, it mangled the key and washer, but it doesn't look like anything was hurt. I will probably remake the shaft and use a set screw inplace of the key to prevent future disasters.

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Just placed an order for the ball bearings for the ways, the machine uses .625 balls on the Y-axis (column) and X-Axis (table), the saddle uses .375 balls and 6.5mmx6.5mm cylindrical rollers for the outside ways.

They needle rollers are much harder to find, I order a hundred rollers from a company in the UK for about $60 shipped, they are 52100 material and should be +/-.0001", I will try and mic them into groups, if there is to much variation I will take them to be ground a few tenths to have them all in family.

I remade the ball retainers for the x-axis, I choose to make them from Delrin. And from experience I figured its best to replace all of the metering units, so those are on the way as well.
 
Looks like I got lucky, out of the 100 needle rollers I ordered I was able to yield 48 (exact number needed) of bearing rulers that all mic'd the same at .2558". The ball bearings also came in and should be +/-.000025.

I determined the only way to remove the column safely was to hoist it directly vertical. So I welded a fabricated a bracket and mounted it to my garage beam, I was able to score a nice used 1-ton chain hoist for $50 on Offerup. I then machined a plate out of 7075 to safely lift the column, I guessed the CG point pretty good as the column came out very easily and looked vertical to the eye.

I am trying to decide if I should remove the ways for cleaning the machine, the machine needs a serious degreasing and pressure washing if I am to even consider painting it. I think it would be be low risk, as the ways are pinned perpendicular in the saddle, and all the other ways are on v-flat, or flat-flat.

Next is to remove the elevation screw and gearing for cleaning. But I am considering cleaning in place, it looks like a lot of work to break down the elevation mechanism.


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Made solid progress last night, I decided I would remove the elevation mechanism if the elevation screw would cooperate. Luckily it did, it was pretty straight forward, I was worried the key from the bevel gear would get lodged in the bearing below when tapping the screw down.

With the screw removed, the jack shaft was then removed as well as the casting. Taking it apart was the right move, the bearings are in bad shape, most of them have grit and do not spin smoothly, some are even really hard to turn.

I was lucky enough to order all 14 bearings from the same seller on Ebay, all New Departure and Fafnir, best part is they all added up to less than $160 shipped.

Spent an hour degreasing the main casting, the paint is flaking pretty bad. So I am thinking of using the Citristrip to remove the paint, I don't think paining over is an option. Light gray or Yates American pale green are my choices..

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More progress, was able to split the spine from the main casting, I never intended to take it this far. But I think I need to high pressure wash the base to remove the grit on the inside, it also allowed me to remove the elevation screw bearing retained, it had some light rusting that was not visible.

The rear of the machine came of smoothly, and I was able take it our fairly evenly, but the pins are longer than I expected. I noticed the pins are slight out of square to the machined/ground surface, not sure if this occurred during removal, or during installation of pin.

I would imagine the machine is aligned, bolted, and pinned. Either way, I will chamber the pin holes to make installation easier.

Next step is to remove paint and degrease the inside of the machine. Then paint the base and start reassembly. I want to get the spine back on ASAP to get the floor space freed up.

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Made some progress, stripped the original paint using Citristrip (works okay), then moved to Jasco (works better). I pressured washed the casting and scrubbed and treated with Metalprep 79. It turns the casting a bronzish brown, I believe this is part of the process. I then scrubbed the casting with pure alcohol and Scothbrite, then wiped with alcohol.

I applied the first coat if Syn Lustro in the color Reeds, it came out to light, I was looking for a Lady Liberty green. So I tried again, still to damn light and minty. I may try one more time tomorrow, hoping they can retint the paint darker.

Once the paint is finalized, I will clean the spine and reattach it. Then clean, strip, and repaint each component as needed for reassembly.

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made some more progress, I changed the color to a silver/white. I stripped the old paint off the column, and applied the first coat today, will need to apply the second coat tonight.

I also reinstalled the spine to the machine, it went smoothly. Once the paint is cured, I will begin the reassembly process of the elevation mechanisn, then reinstall the column.

Once that is completed, the saddle will be stripped and repainted.

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Nice work so far... I missed this thread the first time around, I'll be following along.
 








 
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