Here is a list of all the postings Douglas Johnston has made in our forums. Click on a thread name to jump to the thread.
|Thread: Setting up a bandsaw|
Thanks for the link to the Grizzly site, I have just downloaded the manual for my 6 by 4 bandsaw and it is really superb compared to the one I got with my machine. You would think the UK suppliers could have done something similar years ago to help their customers. Thank goodness for the internet and broadband speeds!
|Thread: Lathe and mill or combination|
Go with separate machines if you can, it is so much more flexible and each machine is designed for its job and not a compromise. You won't regret it.
|Thread: Hex shank drills|
Thanks for the input on this matter. The drills I bought were probably somewhere between poundshop and decent, but nonetheless very shoddy.
I was doing a lot of drilling with a cordless drill (in wood) and the keyless chuck kept letting the drill slip, and of course when you try to pull the drill out you find the drill stays in the wood as it slides out of the chuck. Trying to tighten a keyless chuck with a thin drill stuck in a piece of wood is no easy task and runs the risk of bending or snapping the drill.
The chuck is probably quite worn but not worth replacing so hence my need for the hex drills. I have decent chucks on my "proper" machines and they rarely give a slipping problem.
The answer might well be to make my own but I seem to have a problem with the length of a day. I will seek out Fisch, Bosch and Trend drills to try and get a solution to the problem.
After having a problem with drills slipping in a chuck I bought a set of hex shank drills but was less than happy with them. The hex shank part was simply pressed onto ordinary round shank drills and the result in most cases was very drunken rotation.
After looking online for better quality drills with the hex part and drill made from one piece of steel, I could not find anything suitable. Has anybody found a supplier of quality hex drills?
|Thread: The SURVEY !!|
Just completed my survey and posted it off but felt this could have been done online.
|Thread: Building lathe/mill in cast of concrete?|
one of the best ways to mount a lathe or mill on a wooden bench is to place a concrete slab on top of the bench using a bonding agent between the concrete and wooden top. The concrete should be a decent thickness, made from a thick paving slab or cast in place.
By this means you ensure there is no distortion in the machine if the wooden structure moves slightly over time. There is probably some damping benefit as well when the machine is solidly bolted to the concrete.
|Thread: drilling HSS|
A lot of good ideas for me to think about. The reason I went with the HSS blades was mainly the low cost (ebay is a wonderful place) and the convenience of having the cutting edge ready formed. I did previously think of using gauge plate but was put off by the thought of hardening it without distortion.
The more I think about it I feel I might get away with superglue since the main cutting force will be provided by the stepped carrier. Perhaps loctite 603 might be used here instead of superglue so I must do some experimenting.
What you say is pretty much what I had in mind, but the problem is how to hold the blade in position without any clamping device protruding from the surface which would interfere with the fixed blade. Perhaps superglue might do the job if I can't drill the HSS.
I am in the process of building a PCB cutter using a pair of HSS planer blades picked up on ebay. In order to mount the blades on a carrier it would be beneficial to drill the blades but do not know if this is possible.
The blades are about 300mm long and 20mm wide with a thickness of 3mm. Is it possible to cut a 4mm hole through HSS of this thickness with any sort of carbide or diamond cutter.
|Thread: pcb guillotine|
Thanks for the replies to my query, the hook shaped cutter looks like a good idea and reminded me of hooked carpet cutting blades for a stanley knife so I must give that a try.
In response to the comment about really needing a guillotine, the answer has to be no, but a neat solution to a problem is always appealing to me. There is also the safety aspect to think about since I don't like the idea of breathing in fibreglass dust which is produced from any type of sawing.
Paper guillotines might be another answer but the cheap modern ones don't look beefy enough to tackle pcb material, although a good old fashioned one might be up to the task.
I have been thinking about getting a guillotine for cutting fibreglass pcb material for some time but the cost of commercial units is prohibitive. My thoughts then turned to making one and I searched the web for inspiration without too much success.
Has anybody ever seen plans for such a tool or any technical details such as the best blade angle to use.
|Thread: Late delivery of magazines due to adverse weather|
No sign of my subscription copy of MEW 172 here in Dundee. I emailed customer services yesterday (no reply as yet ), but was that the best email address to use?
|Thread: Surface Rusting in Workshop|
I have been using small silica gel units under a double layer polythene cover on both lathe and mill for the past few years with good results. The workshop is an outside wooden shed which is insulated but not heated.
The silica gel units run for about two weeks or until the gel changes colour and are then reactivated by connecting to the mains overnight. I tend to abandon the workshop for a few months over the winter and let the machines stay cold. With the workshop insulated I do not get rapid changes in temperature which is the main cause of condensation and rusting.
|Thread: HSS v Carbide Tipped Tools|
Sumitomo T12A grade tips are a pleasure to use if you get the ones with positive rake. I too had mixed results with carbide tips in the past with the surface finish being a bit hit and miss.
It seems to come down to the quality of the cutting edge, with a ground finish being far superior, along with the positive rake. I picked up some tips a while ago which were designed for cutting aluminium and were very sharp and had a high positive rake. These tips produced a superb finish on aluminium as you would expect but they also gave a super finish on steel and I use them for finishing cuts on steel (including stainless 303 )
I think the answer is to use any old carbide for roughing but change to a better tip for finishing. Ebay can be a very good place to pick up tips ( I really should not be saying this so just don't be bidding against me!) having picked up some amazing bargains over the years.
|Thread: Digital Rev-counter|
Hello Owen - I built this tachometer a while ago and it works very well on my lathe. It is possible you may have bought the wrong display unit as I fell foul of this myself. The display units come with different input sensitivities ( 50-300V or 0-5V). I bought the 50- 300V unit and could not get the display to count, just as you found, all digits reading zero.
If this is your problem, both units are essentially the same except for R16 on the printed circuit board which needs to be changed from 47k to2k. It is quite easy to do this with a fine soldering iron. I have a letter in 'scribe a line' in issue 153 relating to this problem. I hope this is of some help.
|Thread: Where to buy indexable tool tips|
Ebay is a good source for carbide tips, I have picked up quite a few bargains in the past and often make a suitable holder for the tips. If you are familiar with the nomenclature you can tell the size,shape and tip radius before you place a bid.
|Thread: chuck myford ml10|
I often use a 6 inch 4 jaw on my Myford Speed 10 but you have to be careful to ensure the jaws do not protrude much beyond the body or they will hit the bed. For that reason I would buy a 5 inch one for this machine. I like the ones that have the body threaded and do not use a backplate ,since they have less overhang.
|Thread: induction heating|
Thanks for these responses to my query about induction heaters. These two sites were new to me and look interesting. The open source plans on the site mentioned by Andy look very promising and I will study them in detail when I find the time. Sourcing the bits might be the biggest problem despite my having quite a large electronic junk box.
For some time I have been looking to make a small induction heating coil for general interest and heat treatment of small items. Despite searching online I have failed to find enough information to make such a device. There are plenty of sites showing them working (eg Utube) but very little in the way of practical help in building one.
Has anybody worked out how to build one or where plans exist. I am sure I am not the only one daft enough to want to build one.
|Thread: Belt sander|
I have started to build the belt sander described in ME in Jan / Mar 1995 but there seem to be quite a number of errors in the dimensions given in the drawings. Has anybody built this sander and found all the errors so that I don't fall into any traps that I have not spotted ,or were any corrections printed in later issues.
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