Member postings for old mart

Bernerd, Pratt, Pratt Bernerd, Bison, Toolmex, TOS and Vertex are the better makes, at a price, Chinese vary from poor to excellent, its a lottery with them. I just bought a 160mm three jaw scroll chuck which was unused, and it is very good indeed, when I took it apart to clean it I found that the scroll is a better fit on its bearing then any of the other chucks I have. It runs 0.002" tir at any opening. I took a chance on it, as it was cheap and got lucky.

The DRO for the quill that I bought from Arc was 1/4" wider than the old one on the drill mill. Not much, but it was worth swopping them as the TS is extremely limited for space between the lock and the depth stop. The pictures show the new DRO fitted to the drill mill and early stages of fitting the old one to the TS. Mike made a lever to lock the belt tension and we have finished fitting the motor.

We intend to make covers for the belt in 6mm polycarbonate for easy checking of the belt position. Any suggestions as how to fix them would be gratefully received.

The motor is mounted, not without slight problems. I bought a metre of the 10mm link belt, similar to Fenner nut link. Judging from the length of the old belt, I got two from the metre length, one slightly longer than the other. After fitting the longer one, I recon that the shorter one might just fit too. Fitting the link belt caused a problem straight away, we couldn't get it between the housing and the largest pulley on the spindle. I had thoughts of grinding away at the tight area in the housing, but tried an easier solution first. Taking the pulley off and reducing the top flange of the largest vee. I took off 0.042" off the diameter, and rounded the edges, and the belt just fitted with a little help. The link belts must be a bit deeper than a plain one.

Good to hear the news, and another browney point for Arc.

As long as the screws are not cracked where the key fits, and the jaws are a good fit, a Bernerd is worth more than the average chuck. At the moment, 160mm backplates are in short supply, but if that chuck has front mount holes on a pcd about half the overall diameter, then it can be fitted to a 125mm backplate easily.

It is common for a four jaw independent chuck on a lathe to be a little larger than scroll types used on the same machine. Check the swing of your lathe, a four jaw independent that has about 1 1/2" clearance from the ways would be a good size.

Only leaded brass turns with tiny chips coming off, otherwise it has stringy swarf. I suspect bronze has the same attributes.

I would clean the broken parts and degrease them, the fact that the break is fairly straight and square means that the parts can be clamped together with g clamps. Then drill and tap for 6mm about 12mm from each end. A clearance hole through the outer part and about 3mm deep in the inner part before the threads start. Use the clearance hole to hold the tap straight, and you may need to unclamp the parts to get the tapped hole deep enough. You need at least 12mm of thread length in cast iron, more if the taps will reach. When the first two threads are finished, screw in a couple of SHCS high tensile (12.9) and you can remove the clamps to allow more 6mm screws at about 14mm spacing centre to centre. Finally degrease the parts and assemble with epoxy resin across the break.

You should be able to get at least 6 screws in that length, more if possible. It looks like having the screw heads with thick washers sticking out will not get in the way of anything, this is preferable to counterboring them flush.

Leaded brass is the type that can be noisy, and those tiny chips are worse than cast iron dust.

For a four jaw independent, you might look at Arceurotrade, click on their advert at the top. They sell Chinese and Indian chucks. You would also find that getting a lever type of indicator would be easier than the plunger dti for use with this type of chuck.

You may find a good off licence/ wine merchant sells miniatures and 1/4 bottles of various spirits in the vodka or Polish spirit.

We aligned the pulleys the other day, the motor had to be temporarily fitted. I milled the motor shaft woodruff key down, so it was flush with the shaft od. When the pulleys were in line the grubs crews were tightened down onto the key to leave witness marks. The key was then removed and a 6mm end cutting mill was used to produce two 1.5mm deep holes in line with the witness marks. The 8mm grub screws had their tips turned to 6mm to locate in the key for a more secure drive. We don't have any means of making a key slot in the pulley, and the original wall thickness after boring it to 24mm was marginal. I had to drill and tap the key to get it out, that's what the threaded hole is for

I found extra instructions in the box which are much more detailed, and with some practice, the extra features will become very useful. The dro was destined for the Tom Senior light vertical mill which we are working on as a replacement for the drill mill in use at present. There is very little space to fit the dro on the quill, so it has been fitted in place of the similar dro already on the drill mill. The reason for doing so is because the older unit is 1/4" narrower, and that makes it much easier to shoehorn in place between the depth stop and quill lock.

Tracey Tools do not list a 2.5 X 11 trapezoidal tap, but it is worth phoning them just in case. I would think about using the imperial leadscrew, at least you have a tap to make a new nut if needed. The scale is a bother if you don't have a mill and rotary table to make a new one. A lot of lathe owners have fitted a DRO to the cross slide, if you had one, the numbers on the scale could be covered up with tape.

Edited By old mart on 03/09/2019 19:27:18

It would be a great excuse to buy a small mill, however, they could be made out of plastic or mdf, slightly larger for strength using a router. The mdf could be varnished to make it last longer.

There is a lot more information about it by googling Engineerium.

I have just bought one of Arc's vertical dro's for fitting to the Tom Senior.

**LINK**

It is not quite the same as the one we have fitted to the mill drill, and I cannot fathom the Pre+ and Pre- buttons. I have tried every combination of button sequences that I can think of, but none seem to do anything. Hopefully somebody on the forum has one and can let me in on their secrets.

You need the work running true at the point where the steady is going to be positioned first, then set the steady. The surface of the work needs to be reasonably smooth and round for a steady to work. A disc of card fitted on the work next to the steady will help to keep turnings from getting trapped in the fingers.

If the end of the work is cut square, you should not need a steady to use a centre drill, unless the work is really small diameter, and then you could probably just slide the work down the spindle bore and drill it next to the chuck jaws.

You might try your original plan with the steady next to the chuck, back off one of the fingers and slacken the chuck jaws, and then reposition the steady, do up the finger gently and tighten the chuck jaws last, it might work.

Edited By old mart on 03/09/2019 13:50:33

Edited By old mart on 03/09/2019 13:56:59

If you reposition the front hole using your mill, it would be better if it and the counterbore were bigger and a custom screw were made. Or a stepped bush, perhaps. As already mentioned, use a small diameter test bar in the chuck or tailstock to get a more accurate visual idea of when both fingers are aligned. If the centre lines can be got within 1mm, you should be good to go.

If you don't mind only two of the jaws being really tight at a time, then go for it. The only self centring chuck which is guaranteed to grip on all its jaws at once is a three jaw. So many people are scared to use a four jaw independent, which needs truing up each time, but is the only way to go if positive clamping and true running are of any interest at all. Soft jaws are great for special jobs, but take up much more time to set up.