Boxford Union PD8 Overhaul/Re-build/Restoration

[diesel_boxford]

Bought a nice example, but it was noisy as hell, so knew it needed bearings all round. And it hadn’t been greased since the 80s judging the smell and colour of the grease.
Most of the disassembly was simple, two things tripped me up, removing the high low gear (the shaft that resides in the oilite bearings and has the large funny material gear), and the top spindle gear.
Couldn’t find a thread on a forum that explained these foibles, so maybe this will help someone?
1st pic is off the saw dust accumulated in the switch housing, yuk. Also the divider(?) plate.

2nd pic is the machine, stripped partially.

3rd pic is the grease removed from the gear area, accessed from the top, under the plate,

4th pic is the high low gear shaft, there’s two grub screws, and at the bottom is two ball bearings that retain the gear shaft to the carrier shaft.

5th pic is what really stumped me, as the spindle dropped out, and left the upper drive gear in place. Basically, it’s a circlip that holds it, well covered in 50 odd year old grease. I used the outside of a small pair of flat jawed pliers to get it off, as circlip pliers are near useless (I considered trimming the handles of a large set). Once this is done, it’s plain sailing.

6th pic is all the internals, cleaned and inspected.

Next is the motor, 400v, 3 phase, 0.5hp affair. I’ll hopefully get some better pics of that. Wondering if it can be re-wired to 240v, 3 phase, as I don’t want to buy a motor, just a VFD. There’ll be a posts of a few other things as well.
Any questions, I’ll try and answer them! I’ll have some of my own for sure.

 

[diesel_boxford]

All back together now, and spins lovely. It was so much easier putting it back together.
The gear selector handle was missing when I bought it, so I’ve bought another handle. It was missing because the 3/8BSW threads had been mullered in, so it’s been V-Coiled in the original size.
The motor is a single voltage affair, so I’ve got hold of a dual voltage one. Threw some new SKF bearings in it, cleaned the years of crud out of it and wired it for 240v 3 phase. Awaiting anti tracking paint as the interior motor body has some missing.

Next step is VFD purchase, switches and wiring. Wiring is the problem, as I believe twin core and Earth 1.6mm wire will be fine from plug to VFD, then 1.6mm 3 core and Earth from VFD to Motor. As I’m installing a on off switch between VFD and motor, what size will that need to be?
I’ve been specked a 2.4amps VFD, but the name suggests it is better suited for a 0.40kw motor. Been assured it’s amps that is used, not KW, what’s the consensus here?
The motor draws 2.4 amps max and is 0.55kw (0.75hp).

 

[Nathan.J]

Interesting post- i'm off to look at one of these drills tomorrow.

Are the bearings/ parts readily available?

Where are you sourcing your VFD from ?

 

[diesel_boxford]

I bought the top spindle bearings new old stock, these go in the head of the drill, under the spindle pulley, there’s two.

This is for the spindle nose, there wasn’t a premium brand, so got generic.

This is at the top of the spindle, may not be totally correct, but fit well and available.

This also at the top of the spindle. Must of thrown the box out.

They are readily available, but the prices jump quick from generic to premium, and the premium are normally on back order, the NSK one had to come from manufacturer. I sourced mine from a certain well known auction site, and two from two different bearing suppliers.
Boxford sent me the parts diagram, that kind of helped as it’s for the Mark 2 PD4, but had bearing names and sizes required.
Not needed parts as such, but I doubt they are readily available.

As for the VFD, I’m looking at the IMO SD1 range.
Hope this helps. Any questions, I’ll try and help.

 

[Nathan.J]

Thank you- very helpful!

 

[diesel_boxford]

No problem. It’s quite a simple machine to disassemble, there was three points that really got me, but got them worked out. There was so much grease it was hard to see what was what.
I got another motor, as buying a 240V single to 440v three VFD is pricey, too pricey for me. This is just a project, not a business, I have little use for it really, but there is times I could do with one.

 

[johnt64]

Hi great post I've just bought a mk2 pd8 and am currently in the process of stripping it down, I have emailed boxford for a parts diagram however they have yet to respond, but after reading your post I'm a little more confident if they are unable to supply me with any info

 

[diesel_boxford]

Hi great post I've just bought a mk2 pd8 and am currently in the process of stripping it down, I have emailed boxford for a parts diagram however they have yet to respond, but after reading your post I'm a little more confident if they are unable to supply me with any info

They are good drills, not had any problems with it since the rebuild, drills as true as I need. Trying to mount the VFD controls at the moment.
Not really sure of the Marks, not really delved in to it that far. Does it have the safety bar on the base?

 

[highwood122]

i have one of these drills what use is a VFD ,could you please explain

 

[diesel_boxford]

i have one of these drills what use is a VFD ,could you please explain

Mine came with a 3 phase motor, and didn’t want to change it, so got a VFD for it. It controls the speed, how it starts and stops, and direction of the drill, and creates a false 3 phase by converting 1 phase. You can do the same for 1 phase motors, so you can control them in the same way.