Member postings for COLIN MARTIN 2

Thanks Jim, good point; maybe only the mini lathe specific slide will fit. The trouble with the vertical slides that bolt to the top of the cross slide is that you have to remove the top slide and so lose the ability to move the work in small increments, unless a handheld is fitted to the leadscrew.

Yes, that's the one. It seems a fast way to set up a work piece, especially if the optional vice is used, plus it retains the adjustment of the compound slide, but is it any good?

Has anyone used the Warco vertical mill attachment for the mini lathe, especially their type that clamps in the tool post? I know that it won't be very rigid, but it looks a quick way of carrying out simple milling without a lot of faffing about.

I've been busy doing a few more jobs on the lathe to try and improve it. A few days ago some play developed on the cross-slide area, which I traced to the saddle; on closer inspection one of the saddle shear plates had fractured where the grub screws are fitted. Those who have fiddled with this abomination will know, and those who have yet to do so will find out, what a stupid bit of design this is.

I found that the rear plate was very close to being right without the grub screws, so used pieces of 15thou shim to take out the play, but the front shear plate needed a lot of shimming, which was going to be very difficult to get right, so I found that a small spring washer sandwiched between the plate and the saddle was a perfect fit, so replaced the three Allen screws with small studs, fitted spring washers over each stud, replaced the plate, and fastened it with nylock nuts. Then using feeler gauges, was able to tighten the nuts evenly until the saddle was a good fit over the bed. While the lathe was apart, I also made a cover to go over the handwheel gear housing.

Lastly, I have made a swarf tray that fixes to the saddle, to keep chips away from the leadscrew and lathe bed. You are never bored when you have a mini lathe.

Right, as promised, here is the run-down on changing the spindle to a later type with the mounting for a 100mm chuck.

It is pretty simple; I removed the chuck, took off the cover at the gear end and unscrewed two allen screws that hold on a cast aluminium plate, giving access to the two ring nuts on the end of the shaft. By holding the chuck flange these can be uscrewed using a 'c' spanner and the drive gear and plastic spacer removed. A simple puller has to be devised, using a flat piece of bar with a centre hold drilled; with this held off the end of the chuck flange by two lengths of tubing against the headstock, a long bolt can be passed through the spindle and the nut on the end tightened, drawing out the spindle and end bearing. The remaining bearing is tapped out of its housing.

The top picture shows the new angular thrust bearing on the left, old ball race on right. The lower picture shows old spindle at the top, new at the bottom.

Fitting was simple - press new bearing onto shaft and then feed shaft through the plastic drive gears - although this presents the problem of how to get the bearing into its housing - I managed to tap it in by inserting a small rod through the chuck mounting holes and working around the bearing until it was snug. The bearings are a really tight fit upon the shaft, but because the angular thrust bearings need to be adjusted to remove any end-float, ideally the bearing at the other end should be a tight sliding fit upon the shaft, but after much use of emery cloth, I still was not able to get it as loose as I would have liked. I had to resort to tapping the bearing into the housing, while gently tapping the inner race onto the shaft. finally I tightened the end nuts to remove any end-float and all was well. one small problem is that the tiny parallel key in the end of the shaft is shorter on the new one, so I had to make one to fit. If anyone is ordering the new shaft, be sure to include a new small key.

The new chuck is supplied with mounting bolts that will not fit behind the flange, so I made up some studs and screwed these into the back of the chuck mounting holes. I stripped and cleaned the chuck before use to remove swarf, which other internet videos have shown to be necessary. The chuck is pretty impressive for something so cheap and I only have runout on a length of ground rod in the jaws of half a thou, so all in all I am very pleased.

I'm wondering if a saddle clamp would help?

Yes, good points. I tend to avoid parting off if I can, just using it for thin wall tubes, but it would be nice to have more options. I watched a great video on YouTube recently that went into great depths on the subject and was really informative. The poster was obviously an experienced toolmaker and he detailed how much he struggled to part-off successfully.

Hi Ron,

I think that you are completely right! I believe that the mini lathe lacks rigidity everywhere because it is quite poorly made and flimsy, but having said that, it is a terrific machine for the money. When comparing it to a bigger, studier lathe, which has so much rigidity in the head, bed and cross-slide, the mini lathe just has too much give in the components, so that the work tries to bend away from the parting tool.

I'm only changing the bearings because I have the spindle out, so it was worth trying the angular contact bearings. It was a mixed decision, because I have a spare pair of original bearings by KYO, which I could have used, but.....

Congratulations on your new cross-slide, maybe a new project for me?

Colin

The bearings are available from Arc Euro Trade and are a direct replacement for the standard ones. I'll try to post some pictures.

UPDATE:

after much thought, I've decided that I can only decide after I know what I am going to need!! It is a bit illogical to buy the same size lathe with just a bigger chuck (even though it is a higher spec) without knowing if it will do the job, therefore I have decided to upgrade my existing lathe and see how I get on with that, then go from there.

I have bought a 100mm chuck (on special offer at the moment from Arc Euro Trade) and a pair of angular thrust bearings, which I hope will stiffen up the spindle, and a new spindle with the flange which takes the 100mm chuck. Big thank you to Arc Euro Trade which sent out the parts for next day delivery and Simon at SPG Tools who supplied the spindle and was most helpful.

I was pleasantly surprised when stripping out the spindle and bearings: after reading a lot of negativity about the quality of workmanship on the mini lathe, I found that the parts were pretty well made, although not awe-inspiring like some engineering, the parts are solid and certainly of acceptable quality. I had expected the Chinese bearings to be shot after about fifteen year's use, but both spun perfectly smoothly and with no trace of play, so in future I will have no hesitation in buying Chinese bearings.

Yes, thanks Ron,

I do think that the Chester 920 looks very good, but I'm worried about the weight as I'm not as young as I was and space is an issue too.

The DB7 appears to be a good buy with all the extras included, but does work out at £100 dearer than a similarly equipped mini lathe. As everyone on here has probably found, a home lathe can never be too big, but practically it is a compromise. I don't want to struggle to get a heavy piece of kit into place, which definitely rules out the small Harrison and Colchester lathes etc. I'm in no rush, so I will keep !y options open.

Thanks everyone for the suggestions. Everything is a compromise between, space, weight, money and size v what I wish to do. There is a Chester retail outlet near me, so I will go along and have a look at a DB7VS, and then spend some time mulling things over.

Hi Neil,

Thanks, I suppose we have all been in the position of being caught in a dilemma. I'm mulling things over in my head!

Colin

Hi All,

Apologies for the subject, but I'm interested in other member's experiences along the same route.

I have a Conquest mini lathe that has served me well over about fifteen years, making and modifying motorcycle parts, but two points are a problem: the 80mm chuck is too small, and the poor headstock rigidity makes parting off a real problem. I am considering changing to a 100mm chuck and replacing the bearings with angular thrust ones, but I'm not sure if the 300w motor is going to be beefy enough.

So, I am considering a new mini lathe, which comes with the 100mm chuck and more powerful motor, but by the time all the extras like 4 jaw chuck, faceplate and steadies are added, works out at about £700. Alternatively, I can buy a Chester DB7VS, which comes with the four jaw chuck, faceplate and two steadies for about the same money. Any opinions please? Should I look for a Myford ML10 instead? Thank you.