Boxford Model A stopping on slow speeds...?

Hi all,

real beginner here on the lathe front.... I recently bought a Boxford Model A, which you guys kindly helped me to sort the backlash.

Well, today I had the need to part a piece and when on any low speed, as soon as I touch the piece it comes to a halt!
The gears keep spinning, the belt, etc, I had a look inside and its actually just the chuck that stops spinning.... how's that?

is there something wrong that is not tighten up? the chuck just slows down..and stops. I thought for parting you'd need really slow speeds, but the only way I can do it is like at 250rpm, which seems too fast?

Also while I'm here... if anyone has one of these lathes, how do you change the belt on the motor drive? for the gears there's enough slack to slip the belt over, but on the motor it doesnt slack as the whole fixture moves... or am I missing something again?

I have done a little video of the problem I'm having...

Thanks!

JP

Is the back gear partially engaged? The level on the front of the headstock I think is in the wrong position I’ll check in the workshop tomorrow morning!

Edited By Johnboy25 on 23/10/2018 23:41:14

Looks like you have disconnected the drive dog between the stepped pulley and the headstock spindle but have not engaged the backgear by swinging the backgear into position via the backgear selector handle. Not totally familiar with the Boxford (we made our own local SouthBend clones here in Oz which are the same but subtly different.) so can't point out the exact lever and position for this. But if you look at the manual or online resources under "back gear" it should tell you. NOTE: Engage or disengage the back gear with the motor and spindle stopped. Don't try it under power. Gear teeth will suffer!

I think it is just as well that the chuck stopped, You are not holding onto very much metal for a parting cut so part will more than likely get pulled out of the chuck.

Some discussion here on Boxford back gear use at about page 5 and 6: **LINK**

Just noticed that. Jason is correct, that will pop out once the parting off tool actually started cutting. Dangerous.

I'd say the pulley inside the headstock has grease or such like on it from the back gear assy and the belt is just slipping on the pulley and hence no drive once you start machining.

If you're a total newbie and working on your own then drive slip is actually a good thing

It's miles safer plus it forces you to acquire the skills of cutting successfully on low power

Once you can do good cuts on low power you can ramp things up bigtime later on

EDIT

I cursed my drive slip in the beginning but it really helped me as my ability improved, took about 12 months

to get the basics, working a few hours every couple of days

You will never get the same skills on a big powerful machine because they drive the cut right through every error you make and you never notice any minor but relevant issues

Edited By Ady1 on 24/10/2018 10:12:00

Video here on setting the "knobs and levers" on a Boxford. Backgear etc is covered in the first minute or two. The first lever, the one over behind the left hand end of the main spindle (shown at 1.00 min in the video) may need a bit of jiggling and perhaps rotation of the main spindle by hand in order to get the gear teeth properly meshed.

Edited By Hopper on 24/10/2018 10:25:41

Edited By Hopper on 24/10/2018 10:29:52

I think Hopper is right. I don't think a greasy belt would have such a dramatic effect; back gear drive is not connected, and Jason is most definitely correct on the weak grip on the job, but those points aside I had rather similar problems on my Sabel lathe, the Smart and Brown clone of the Southbend.

The 4 step pulley cluster on the Sabel countershaft is made in aluminium and over many years prior to my ownership the belt to the spindle had worn the pulley grooves in the aluminium to pronounced J shapes with the belt itself actually running on the bottom of the groove. I could easily bring a turning job at any speed to a halt with just the lightest cut and belt tensioning only made things worse. Once stopped in this way, light hand grip alone on the chuck was quite enough to prevent it from turning.

I was able to correct that by fitting a cast iron pulley cluster, only to find that the aluminium two step pulley on the motor was worn in exactly the same way, and had the same effects on cutting. I re-machined that pulley and swapped the belt for a slightly wider link belt type to compensate for the wider motor pulley grooves. These changes have transformed the lathe

In a past ownership the lathe lived in a woodworking workshop and I suspect the timber dust was the cause of the groove wear. The motor was full of such dust. It was not easy to spot either and only properly visible when compared to a corrected ground grooving tool

Brian

Edited By Brian Wood on 24/10/2018 10:25:28

Edited By Brian Wood on 24/10/2018 10:36:27

Agree with Hopper. The lever with the latching device on the right front of the headstock is the sliding gear lever which disconnects/connects the dog clutch inside the headstock to give "direct drive" from the pulleys to the bull wheel or to disconnect this drive. Yours is set to the left, which disconnects the dog clutch and for the chuck to rotate the back gear lever on the end of the headstock (a plain cast lever, no latching) needs to be turned to the right to engage the backgear

If you are not intending to use backgear, then the sliding gear lever needs to be unlatched and moved to the right, the chuck will need to be rotated at the same time so the dog clutch can connect. Then check the back gear lever is turned to the left to disengage the backgear.

On the belt drives, you will have found the lever at the rear of the headstock which takes the tension off the belt drive from countershaft to spindle - this is adjustable by turning the hexagon part in the middle of the linkage, this has both left and right hand threads at opposite ends so turning one way tightens and t'other way slackens.

The motor to countershaft belt tension is adjusted by a knob on the motor mounting plate which is simply a screw to raise and lower the mounting. If you need to change the belt simply lift up the motor until you get enough slack.

Edited By Robbo on 24/10/2018 10:54:15

On the Box Ford A that I have use of the back gear lever, left rear of head stock seems to come out of gear if you don't pull it down properly.

On this one I don't think the motor set up is as ex factory, the motor is behind the jack shaft, so I remounted it on a hinged plate, motor belt tension is by gravity. I must get a photo of the set up, I use it on a number of machines.

Ian S C

Hi all, thank you very much for your replies.

First of all, many thanks for pointing out I dont have much holding on the chuck for parting! That was incredibly stupid of me!
I'm a beginner but been using a lathe for about 6 years, so I'm alright with the facing, parting, etc and even grind my own tools for the shapes I want.
but thanks for pointing it out because it completely slipped my mind on that one...health and safety head wasn't working here!

Just been in the garage and you are all correct! I missed engaging the back gear! I lost count how many times I looked at the little plate to make sure I had it all on the right settings...and missed that!
I have just tried it now and it's fine.... with the back gear engaged it doesn't stop... damn.. I feel dumb! such a simple thing!

Also thanks to Robbo - there is indeed a bolt on a spring that holds the motor, that allows to lift it and change the belt on the motor! I did have a look around but is so tucked under there that I missed it. so thanks for the information.

I would like to say a big thanks for all your responses gents, I really thought there was something major wrong with it!

JP

Such a simple thing, yes. But the reason we all guessed the cause of the problem correctly is we have all been there and done that ourselves! (More than once, I'm sure. )

On my later Boxford the back gear has a screw on the lever to lock it in position, that screw also operates one of the interlocks so you can't start the lathe unless it is fully engaged, I guess that was done as a result of lots of people doing what you did.

Baldric.

Just another small question, the nipples all around the lathe.. are they for grease?

Reason I ask is my old Myford and the southbend both had cups for oil to drip, more the myford than the southbend, but the Boxford... is there such thing as oil that can be shot in there?

or is actually just grease, with a normal grease gun?

thanks!

btw.. used the lathe today, now with the back gear engaged.. what a beauty!

I used grease in the 2 nipples on top of the head stock as per the user manual, oil every thing else, someone may shoot me down, but I'm just going by the book.

Ian S C

JP....

I too use a straight SAE 20 mineral oil for all the places with the Ball Oilers and one or two squirts of Castrol LM grease on the Headstock now and again depending on usage. The tightness of the drive belts are optimised to try to reduce general vibration to a minimum.

Search either this site or the web for a PDF copy of 'Know Your Lathe'. this is the Boxford publication of the lathe manual and some good operating practice.

John

Its oil in all the ball nipples. and grease in the 2 headstock points. I see your headstock has a nipple for the grease at each end of the front of the headstock. I have only seen Boxford A s that have a grease cup in theses locations. With these you unscrew the cup, fill it with grease, and screw it back on, so forcing a measured amount of grease into the spindle bearings.

As you are using backgear there is an important lubrication point which is not obvious and is accessed from the rear of the headstock. You can see an oil ball nipple in the middle of the shaft carrying the backgears at each end, but there is also an oil reservoir inside the 5-way pulley cluster. This is accessed via a grub screw in the base of the second groove in from the chuck end of the spindle. The grub screw is removed and oil put in until the reservoir is full, and the screw replaced. This is an important part of the backgear procedure, as the pulley cluster is deprived of the support of the bullwheel when backgear is used.

Boxford list a variety of oils and greases, most of which are now out of date, but ultimately a standard SAE 20 mineral oil (as mentioned by Johnboy25) and a general purpose bearing grease are adequate.

Picture of the rear of the headstock showing the oil points, the grub screw has been removed to make the hole easier to see. (BTW I do have a new link belt to fit eventually!)

I'v got "Know your lathe" on my lap top, have not got round to printing it out for general use yet. I'v been using SAE 30 oil, same as I use on my lathe at home.

Ian S C

Boxford Lube Chart.