Restoring a Rockwell/Delta finishing machine

[firestopper]

I recently purchased this machine from Public Auctions, It came out of a local H.S wood shop in west Tucson.
The serial number indicates it was built in 1983 and for a older machine all the parts are present. It does have the typical damage found on many of these older machines due to poor tracking on the abrasive belt.
The disc is 12" and the belt is 6"x 48" powered by a single phase 230v motor.

 

[firestopper]

The teardown and inspection shows the typical grooving found on the belts main cast (cast iron), top cover (die cast aluminum) and belt end cover (16 ga mild steel). The main drive bearings appeared to be good while the upper idler roller had excessive up/down play indicating bad bearings or worn shaft. All bearings will be replaced in any case.

 

[firestopper]

Heres the setup I came up with to press the shaft out of the idler roller. The cast iron yoke is easily broken if not supported during this operation and finding a new one is pricy. The rollers are supported with 1 2 3 blocks and the lower cast yoke is supported by a short section of pipe (faced to fit) for a solid setup.

Once apart, it was obvious the shaft was the cause of the play and probably the main reasons for the tracking issues the led to the grooving. I was able to source the replacement bearings locally for $28 total and the shaft was found online for $34 (precision ground). I could have made a new shaft but the price was right.

 

[firestopper]

The cast iron groove and and aluminum groove where repaired with JB Kwick-weld while the end cover was welded with the mig.

The back side of the cover was also grooved about 50% through and required some welding being careful not to distort.

 

[firestopper]

The table trunnions where repainted in black and test fitted. The receiving cast required slight reaming for a smooth in/out motion that locks/unlocks the table adjustment.

The remaining cast iron was blasted and masked off for paint. I use a small fine file to cut the tape for detailed masking.

 

[firestopper]

The main drive housing was painted and new bearings installed as well as the upper idler roller assembly. I special tool was made on the mill to install the bearing retainer for torquing. The crown was verified on both the upper and lower rollers. A worn crown also leads to poor tracking so its important to check. There only need to be a 1 degree of fall off. The tracking adjustment knob will fine tune the the belt when all else is working properly.

Finding center using a co-axeal indicator makes it quick and easy.

Made the adjustments and a couple of passes later the tool is ready to be demurred and put to use.

Bearing retainer installed and torqued.

 

[firestopper]

Got the knobs painted with hi-temp silver. A quick 20 min cure at 200 degrees in the BBQ will provide a durable finish.

Probably should have posted sooner, the manuals and illustrated parts breakdowns where down loaded free and a folder created.

This photo shows the shape of the upper idler crown as mentioned previously. Poor photo, sorry but I think you get the picture.

The main belt roller crown.

Hoping for good weather this weekend to shoot the paint.
I hope someone can use this information and shoot me a PM if you need P/N's or any other questions if you have a similar machine.

 

[firestopper]

Got the parts painted today. The weather was perfectly calm and 70 degrees.

The repaired top cover.

Hammer tone brown/copper sprayed with my 15 year old Cheapo Harbor Freight HVLP gravity feed.

Repaired belt end cover.

The family photo...

Now on to the lower base cabinet.

 

[firestopper]

Pulled the motor out in prep for repairing the lower cabinet. Turns out the motor was loaded with saw dust and the shaft would not turn smoothly due to a bad front bearing. Pulled both bearings and used shop air to clean out inside of motor.

I'll pick up new fully sealed bearings today and reassemble so I can continue on the lower base.

 

[firestopper]

These bearings are very common and the local bearing house stocks 100 of both fully sealed and shielded.

I went through my scrap pile of pressing tools I've turned over the years and found a sleeve that was a few thou larger than the shaft and contacted the inner bearing race only. Worked good for this application.

Reassembling of the end cover was done using the long assembly bolts (4) by tightening each bolt a little at a time alternating to keep things even allowing the bearings to seat into receiving bosses.

Thats all I had time for after work.
Expecting 79 degrees and calm winds on Saturday for spraying the lower cabinet and finish this project up.

 

[firestopper]

Prepped the base cabinet and electrical enclosure for paint Friday after work. Sprayed Saturdays morning and finished just in time as the breeze really picked up the rest of the day.

The silver hammer tone laid down nice with three medium coats.

You can see the texture better in this photo of the enclosure.

I also trimmed back and tripped back the wires on the motor, switch, and power supply that connect inside the enclosure. After 34 years, a few of the strands where broken on each connection. I also used crimped connectors after tinning the wires. This should outlive me.

With the paint on the machine now cured for seven days, I started assembling the tension mechanism and the stop block for the rapid setup of 90 (0) - 45 degrees on the belt main body.

 

[firestopper]

I also picked up new hardware (cap screws) that replaced the old slot headed fasteners for a fresh look. As mentioned previously, all machined mating surfaced where masked for painting. Originally from the factory most everything was painted and movement of adjustable parts where sticky at best.

I also changed the red color of the pointers to safety orange.

A new roll pin was used to reinstall the stop block. When the block is down, the table can be adjusted throughout the range up or down. There are two threaded lugs on the table mounting bracket that contact the stop block in the up position. This allows for a rapid adjustment to 90 (0) degrees and 45 degrees. The threaded lug has set screws for fine tune.

I will also fab up some castor brackets that keep the machine 1/2" off the deck and work on the vacuum system next.

 

[firestopper]

Got bored and went into the shop to tinker. I really had no intentions of doing much, but the wind outside kept me indoors.
I decided to wire in the switch and enclosure but one thing led to another and by the end of the day this happened.

I need to pick up a fresh capacitor for the motor, then install motor and the restoration is complete. Its been good to get back into the shop after recovering from surgery.

 

[Coolerman]

Damn! That looks great! I love older machinery. It is built so much heavier than the cheap China crap on the market today.

 

[firestopper]

Thanks man, mostly cast iron, zero plastic.

 

[red66toy]

Amazing job! Beautiful! I love old machinery, great job bringing this one back to life.

 

[firestopper]

Amazing job! Beautiful! I love old machinery, great job bringing this one back to life.

Thanks, its good to be back and working with my hands again. This machine is a year younger than my 40.

 

[NicksFJ40]

Looks great, You did a fantastic job. I picked up a Rockwell 31-520 for $30. I'm waiting on parts from Renovo before I start my restore. Do you know of any other part venders for these old machines?
Thank you
Nick

 

[firestopper]

Hi Nick,

There are a few internet venders but many parts are discontinued like the faucet knob on your machine. Renovo was the only source that had an idler shaft for the top roller for my machine. I was planning on turning one, but for a precision ground shaft for $34, it wasn't worth my time. Google "Rockwell/delta 31-520 parts" and see what comes up. I would suggest having p/n available to plug into the search bars once you start looking. This link might help:http://vintagemachinery.org/pubs/2793/6590.pdf

Although not the exact machine, many parts and setup methods are the same or similar. You might also find more information on
vintagemachines.org . I have also seen parts on eBay for finishing machines, but can get pricey. You paid very little for your machine so hopefully have room in you budget for parts you need. You might also be able to fabricate some parts needed as well. I can tell you one thing for sure, don't buy any bearings online if you have a local bearing house near you, but inspect the unit carefully before you start throwing money at it.
The lower drive roller nut is L/H thread and the top idler roller cast iron yoke is easily broken when pressing out the bearings so be careful and presoak with quality penetrating oil.

This stuff is amazing penetrating oil

Heres another link on pressing out the idler shaft:Delta 6x48 Sander Shafts - VintageMachinery.org Knowledge Base (Wiki) . I also supported the yoke with a piece of pipe faced to fit under the setup on the press. 123 blocks supporting the rollers and pipe under yoke (the link only shows supporting the roller)
If you want I can give you Koyo sealed bearing P/N I used, but you'll need to verify your machine share the same bearings as the 31-730 (I have a hunch they do).

I see potential in your belt sander.
Other links, hope they help Nick.
Delta 31-550 Parts List and Diagram - Type 1 : eReplacementParts.com
Delta Manufacturing Co. - Publication Reprints - No. 31-520 6" Abrasive Belt Finishing Machine AFM-6 | VintageMachinery.org
Delta Abrasive/Sanding Machines Parts Lists

 

[firestopper]

The last piece of the restoration came via snail mail. A replacement warning label completes the restoration.

Not identical to the original, but same part number and for a finishing machine.

Old warning sticker.

Done deal.