Member postings for Douglas Johnston

It's interesting that there are many different feelings about varifocals, probably because no two brains have exactly the same connections. I have used varifocals for quite a few years and my experience was very good right from the start with only a few days of adjustment.

My latest pair are rimless with small lenses and they work perfectly for me. The only way to see if varifocals are right for you is to try them out. I think most opticians will let you return them if they are not suitable and supply you with a different type at no extra cost.

Doug

If you use a good quality positive rake carbide tip you can get a superb finish even on the smaller hobby lathes. I think many people are put off carbide tips after trying poor quality or inappropriate types. If you look at a solid carbide milling cutter, the edges are very sharp and give an excellent surface finish. Lathe tips of the same quality will produce excellent results as well, but don't expect good results from cheap imported tips of dubious origin.

Doug

I have a small lathe (Myford speed 10 ) and mounted it on a concrete slab 3" thick and this makes a very good rigid setup. The granite slab is a super idea but needs to be a decent thickness, 1" would be too thin, I would go for 3" at least if possible, but it would be very heavy . The good thing about a concrete slab is that it can be cast directly where it is required and does not need lifting.

I have always thought a granite tombstone would make an ideal base and then when the time comes to shuffle off this mortal coil you could be laid to rest alongside your beloved lathe.

Doug

Yes please, get rid of the word "model" from the title of MEW, it sends out the wrong signals to many people. From now on let's have EW.

Doug

I have been reading the latest copy of MEW (217 ) and on page 9 in the article about updating the universal pillar tool the auther mentions having to increase a bore from 0.551 " to 0.554" in order to fit a needle roller bearing.

I seem to remember reading that needle roller bearings should be a press fit so that they then provide the correct internal diameter once fitted. If this is correct the bore should have been left at 0.551" and the bearings pressed in.

Does this make sense or am I talking rubbish?

Doug

I built a Shumatech 350 a number of years ago when the cost of commercial units was quite high. I soon wished I had'nt bothered since the system never worked very well and the price of commercial units came down considerably.

After a few years I bought a commercial unit with glass and magnetic scales and there was simply no comparison with the Shumatech system. The new system is rock steady and has performed perfectly for a number of years.

I know price has to be considered but if funds are available I would urge others to go down the commercial/glass/magnetic scale route and you won't regret it.

Doug

When I was building my Quorn I thought about using hard chrome bar as suggested by CoalBurner but could not find a supplier willing to supply the small amount needed. Is there a supplier in the UK able to supply small lengths?

Doug

Can I introduce a word of caution here. I finally completed my Quorn last year, only took 19 years from buying the castings, and while I like it a lot and have used it a fair bit, I would not repeat the process now. I can well understand the attraction of building and owning a Quorn and as a machining exercise it was great fun, but from a financial point of view it simply does not add up.

If I was starting now I would look at some of the simpler designs that are around. For all its beauty the Quorn is fiddly to set up and if , like me, you just need it for drills and end mills, the simpler designs would be a lot cheaper to make and much quicker to build.

Doug

Cotton buds slightly squashed with flat pliars and pressed into the outer end of the scroll, then use the chuck key to wind the cotton bud to the centre of the scroll. Repeat a couple of times and the chuck is clean. Toothbrush for the individual jaws, a dab of slideway oil on each jaw before replacing and the job is done.

Doug

You are quite right John, I have made some in the past myself and it would get round the problem of being too hard to cut. It is just that they are so cheap from CTC and I bought a smaller sized one a while ago from them and it was very nicely made. By the time I bought a closer and a hefty chunk of steel in the UK I could well have spent more than a very nicely made one from China. The global economy can be a bit crazy!

Doug

Thanks for the replies, I will go ahead and take the risk and see if I can increase the bore. That link that Tom provided is very interesting and is a company I was unaware of,I must take a look next time I am in Glasgow.Unfortunately they only list an ER32 straight shank collet holder with a shank diameter of 32mm and I need a diameter of 1". Their prices are quite good though and no long wait from China.

Doug

I want to use an ER32 collet holder with 1 inch parallel shaft to sharpen larger size drills on a Quorn grinder.CTC in China sell them at a very cheap price but the bore through the 1 inch diameter shaft would need to be enlarged to be useful.

Does anybody know if this type of collet holder tends to be too hard to bore out with carbide tooling?

Doug

I have a stepper motor drive connected to the right hand end of the leadscrew of my Myford speed 10 lathe and use the enable input of the driver to disable the motor when it is not running.This arrangement has worked fine for some time but I do sometimes feel uneasy when I use my mandrel handle for screwcutting.

The turning of the mandrel handle rotates the stepper motor (incidently there is very little resistance caused by the motor  and I do worry about the back emf generated by the motor and the effect this might have on the well-being of the driver electronics. I presume that modern drivers have protection built in to prevent damage of this kind, but I still worry.

Doug

Might be easier to keep the 8mm diameter and modify the handwheel, although that may not always be possible.

Doug

It does not take long to make holders and they cost next to nothing as well. The proper torx screws are also available on ebay. The triangular tips are the easiest to make holders for since thay just need cutting to depth in a straight line at a 60 degree angle at the end of the holder. The diamond ones need a bit more work but are easily copied from commercial ones. Not the least bit boring, but if it is boring you want, these holders are quite easy to make as well!

Doug

I have been using ice stick trays from the pound shop for some time (two for £1 ) and find them excellent for storing milling cutters. I also have a number of the type shown by Norman, but I found the cutters tended to hop out of them if the drawer was closed too abruptly. The ice stick trays have deeper grooves with solid ends which prevent the cutters riding up and out.

Doug

Hi Jay,

I ran a smaller Myford (speed 10 ) and a Myford VMB mill in the loft for a number of years before moving everything outside to a purpose built wooden workshop.

While it did work it was far from ideal and I would never do it again. The noise seems to be amplified in the rooms underneath and it can be downright antisocial to others in the house. As has been mentioned I also had a problem with bad condensation at certain times of year, a problem that was cured when I moved the machines outside in my insulated workshop.

We all have to decide these things for ourselves, but my advice would be to leave the loft to the household junk and the spiders and move the lathe outside.

Doug

I noticed an advert on TV the other day for the first part of a magazine about building a 3D printer . Since the first part only cost £2, I had a look in a few newsagents but there was no sign of it and I gave up looking. Looking at the small print on the advert I noticed there are 90 issues of the magazine ( 89 of them costing £6-99 each! ) so the total cost of building the printer would be very high, and I wonder if there is enough demand for this venture to be viable.

What then happens if the magazine bites the dust after a number of issues? I also see that the version sold by Maplins has just had a £200 reduction in price, which suggests that they are not selling well.

Doug

Unless things have changed recently, all the MT blanks I have bought in the past have never had a hardened shank. In fact I have often had to remove the odd ding from the soft MT surface in order to provide a good fit.

Doug

One of the best ways of mounting a small lathe on a wooden bench is to acquire a thick concrete paving slab and bed this on to the top of the bench with flexible mastic, then bolt the lathe to the concrete.

You could even cast your own concrete slab or use a suitable lump of granite, perhaps an offcut from a tombstone maker ( or would that be a bit morbid ! )

Doug