Member postings for Andrew Tinsley

Sounds that you need more heat, I have often used a 20 to 30 kW torches and for a well known 7 1/4 gauge boiler, an even bigger torch. I found that it is best to get the job up to temperature as quickly as possible, as even Tenacity No 5 flux can give up after prolonged heating to get to temperature.

I normally use a very large propane burner for general heat and oxy acetylene for say the tubes in a tubeplate. I find it a quicker system and less liable to destroy the flux in a big job.

You need to know what you are doing with oxy acetylene as you can melt the copper with ease. People like Alec Farmer, nearly always used oxy acetylene with or without a propane torch and I think that he was a better boiler maker than most of us ( disclaimer for the pro boiler maker that frequents the forum!).

Andrew.

Thanks everyone for their input,

The 920 lathe is still a current Chester offering. I have no problem in turning 10 mm key steel down to 10 mm round, leaving one end at 10 mm square This is needed for the securing U washer, to retain the gear. It is a much faster way of making the pin, much less turning is required.(You need to turn down a 15 mm round bar for the suggested method)and no second milling operation.

I understand that key steel is a relatively high carbon steel so should have some of the properties of silver steel.

The real problem is the bush. This can be bored internally to 10 mm but it cannot be turned to the 14 mm external diameter, because it has a "male" key (5 mm x 2.5 mm) on the outside, which engages the gear key way.

As to surface finish, I have seen the studs on a new lathe, to say they are rough is being kind!. They were not case hardened according to my warding file.

I can see no way of making the bushes in one piece with the kit that I have, so I will have to fabricate the bush, again no big problem. I will investigate Clive's suggestion and some of the materials that have been mentioned.

Again, thanks everyone.

Andrew.

The shafts and bushings on a friend's 920 lathe are showing a fair bit of wear. These are the shafts for the change wheels and the bushings are the keyed bushes which fit into the change wheels.

Chester has no stock, so I may have to make new shafts and bushings from scratch, which is not a major problem. But what to use in the way of materials? Both shafts and bushings appear to be mild steel, which could be one of the factors in the amount of wear.

I was going to make the shafts from key steel, those with 920 lathes will know why. The ends are 10 x 10 mm square which transits into 10 mm diameter round.

But what is best for the bushings? I have some 14 mm O/D by 10 mm I/D stainless tube which is a perfect fit for the bushings. At least it is a dissimilar material! or should I use brass or bronze?

Having machined most of the bronze family, I am not enthused, as I find it a difficult material to work.

I suppose the 920 lathe is definitely cheap and cheerful, so do I just use mild steel again? Suggestions would be very welcome.

Andrew

Thanks Martin,

Not thinking straight this afternoon. I can get a 10 x 10 mm holder from Jenny Blackwell. Problem solved!

Andrew.

I am looking for an 8 x 8 mm indexable holder for use with external threading inserts.

The tooling is for an ML10 fitted with a Myford QCTP. Unfortunately this restricts the tooling to 8 x 8 mm shanks.

The only one I can find is from RDG, after looking at the usual suspects. RDG do not state the type of insert that this holder uses. I have been told that it is an uncommon type and one is stuck with the RDG offering.

I have no idea if this is true or not. Other types of 8 x 8 mm holders can be had, but are for commercial use and command prices which I cannot afford.

Anyone know of other offerings that are not hugely expensive and take common threading inserts?

Andrew.

Edited By Andrew Tinsley on 14/05/2021 18:04:50

Amused by the comments on painting! When doing a refurb, I always try to repaint to a high standard and do the cosmetics needed. Why? Well I am a very messy machinist and I tended to leave my machines in a swarf covered and filthy state.

Since I have adopted the pristine machine mantra. I find that I tidy up and clean, as I can't stand such a nice machine being filthy! So there is a good reason for keeping machines in a smart well painted state.

I hasten to add that any mechanical defects are taken care of and have a much higher priority than painting!

Andrew.

I purchased a litre of Model Technics D3000 from Ebay only a couple of months ago. There are several sellers to choose from. Just search for Model Technics diesel fuel.

Andrew.

Hello Vic,

Yes I agree with you. I only referred to the gauge as a DTI because Mitutoyo themselves use that terminology.

The give away should have been the thread .Plunger types have a thread of M 2.5 for the contact point, whereas lever style DTIs have a thread of, I believe, M1.6 for the contact point.

Andrew.

Thanks everyone,

Diogenes has the answer. Two for £4.25! Scoured Ebay with various descriptions last night, but never tried DTI Ball Contact. At that price they must be Chinese or Indian, but better price than £7-8 each direct from China

Andrew

Thanks Michael,

Now why didn't I think of that myself!

Andrew.

I have a newish Mitutoyo 2046 DTI (M2.5 x 0.4 thread for contact point). Tried all the obvious and non obvious suppliers and either the asking price is silly money (£20 for a DTI that can be had new for £40!). or there is a whopping minimum order charge, or the P&P is astronomic.

Plenty from China for £7 or £8 pounds, but I don't like supporting China's industry if I can possibly help it!

Making one is difficult for me as the M2.5 thread is a bit too small for my failing eyesight to cope with.

Any suggestions? Apart from the obvious "OP is tight fisted" which I am!

Andrew.

I use an Aldi el cheapo set and they have been excellent so far.

Andrew.

+1 for Bullfinch. They have been extremely helpful whenever I have needed information. Totally different to Sievert / Rothenberger's unhelpful staff.

If you don't go for Bullfinch (shame on you), then Bernzomatic have proved to be totally reliable for me.

Andrew.

I have Dewhurst switches on several machines. Provided they are switched rapidly. arcing problems are minor. I have only ever burn't one contact out after nigh on 50 years of regular use. It took me 30 minutes to replace the contact as I had spare tungsten rod.

The presumed wisdom on this site re Dewhurst switches, is overdone, to put it mildly. Will the naysayers please send me their "not fit" for purpose Dewhurst switches.. I guarantee to find them a good home.

Andrew.

Although I have difficulty in believing this, I found that the reception varies with the leaf coverage of the many trees in my locality. I would have expected this attenuation effect for very much higher frequencies than VHF.

As an aside I have found that DAB radios will shut down if too close to an inverter. I have same, driving low voltage LEDs in a bathroom. Bring the DAB radio to near the bathroom door and it closes down if the lights are on!

Andrew.

Sorry, should have read the post more carefully, apparently the ML7 adapter doesn't fit. I would simply drill and tap the head stock and make it fit!

Andrew.

Is this the lever action quick change collet chuck that is being talked of? If so then the part is very simple to make, some square bar and a screw or two.I don't know if the fixing is different on the Super 7, but for the ML7 it is a simple 20 minute job, even for a beginner

Andrew.

Thanks David,

Mine is a totally different machine, I really must get a picture and find how to post it. The belts however are the same style as the one I have.

I will have to use an engine crane to shift mine. I think it must be well over 100 kilos.

Andrew.

Hello David,

Thanks for the info. My drill is definitely 6 speed with 3 step pulleys on both motor and spindle, so it is a different model by the looks of it. I need to turn up a new high speed pulley ( the pulleys are changed on the motor for low and high speed range). My available lathe has too small a centre height to accommodate a new high speed pulley, so I need to wait until I can use a friends lathe.

If you can give me any more information on belts I would appreciate it, mine is approx 20 mm wide and is a very thin flat belt. I have about 125 mm adjustment on the motor position which means I can use one belt size for both high and low speed pulleys.

I have finished mechanical work on the drill and just need to rewire it. After sweating blood, I managed to change the 2800 rpm three phase motor from star to delta. I must have done this for at least a dozen motors, but this one was very difficult to get at the star point and the winding insulation was in a delicate state! Amazingly the motor ran on an Altivar 28 VFD. I suspect the motor won't last too long and when it fails,then an expensive rewind will follow!

It has been in a dismantled state for so long that I had forgotten how massive it is. I bet it easily outweighs my Centec 2B. I don't expect that it will be used much but I didn't want it to go for scrap.

Regards,

Andrew.

Edited By Andrew Tinsley on 03/05/2021 13:27:39

It now seems that you can get the dynamo brushes with no problem. When iIchecked a few years back, could not find any!

Andrew.