Member postings for Ian P

Machining the head from solid looks to be quite a challenge!

If the fins are cut with slitting saw then the valve stem housings would get slotted too (based on the image Jason showed). Some of the other slot details look tricky too (like the ones parallel to the bottom face).

Endmill on rotary table for the spring recesses would have to be very long as there is only a 1/8" annular gap, similar cutting tool problem if done on the lathe faceplate.

Ian P

I only speculated that the OP was enquiring about the external machining rather than the valve seat side of things and whilst a Rotabroach or some sort of hollow endmill might do the job it could be more cheaply done with a standard slot or endmill with the head set up (on a simple alignment spigot) on a rotary table.

Probably lots of other ways of machining the recess, but best wait until we know more from the OP (I dont know the engine and there is not enough of the drawing to show the full profile), maybe the head is a casting with the spring recess already present.

Ian P

Just a thought, I wonder if the OP referring to a method of cutting the external annular recess/counterbore that the spring sits in?

Ian P

David, how did you hold the collet?

Ian P

I would be interested to know where the runout comes from in the first place. Maybe the bore is accurately concentric with the OD but a loose fit on the motor shaft also depending on how the pulley held on the shaft may throw it off centre (grubscrew/keyway). What does the bolt on the centreline do?

If the pulley is a solid lump of ali I would be tempted to put a conical bore in it to accept an off the shelf 'taper-lock' bush.

Ian P

I think that MyTimeMedia might be the only source to categorically state that that the 'majority' of users on this forum are 'hobbyists'.

I dont know how one could determine the ratio of model engineers here compared to the rest of the members but as a non model maker I certainly do not feel lonely.

Ian P

I think this task is being seriously overthunk!

Depending on the intended purpose, if this was a 4ft length ground bar between two 3" long journals (created by line-boring) then one might need be able to get a very close running fit. For Sam's application (bearing in mind we dont know how true or straight the shaft or the tube is, nor do we know the surface finish of the shaft.

For a a shaft running in a plastic bearing to have a long life, the shaft surface needs to be very smooth and preferably polished. There are plastics specially formulated to run without lubrication and ready made bushes are an online purchase away (Google IGUS).

The longer the bushes are (and 3" is unusually long for a 1" shaft!) the more the straightness of the shaft becomes important. I know nothing about boats and rudders or what forces are involved but even a 1" shaft bends when it has overhanging loads at its ends so aiming for a close engineering fit seems a bit OTT for this application.

If you do want to machine your own bushes from Acetal then rough drilling/turning the OD and ID oversize with the stock projecting from the chuck followed by turning and boring to size with very sharp cutting tools is the way I would recommend. My only other recommendation would be not to make the bush a press fit in the tube as its likely to buckle before its pressed all the way home.

Ian P

Certainly looks the same stuff so I spoke to their sales department today. They only have the same 100mm wide strips which they purchase from SAS International in Reading Berkshire who are a big player in the fitting out of prestige buildings. From the SAS website it does not look like they actually manufacture the raw materials but they are major wholesalers and supply a lot of the partitioning companies.

My search goes on.....

Ian P

I contacted the company that Jason linked to and they stock cut strips (100mm wide 3m long) of the exact material I am looking for. However they are unable or unwilling to give me the name of their supplier or even what the material is called, as far as they are concerned its just 'skirting laminate'

TBH their supplier might not be able to help as the sales person I spoke to said they had tried to get 150mm wide strips from them and been told (the warehouse) only stock 100mm.

I'm pretty certain the strips are cut from large sheets as visually the long edges appear to have been sawn whereas the ends are definitely unfinished.

Its frustrating to know this material exists and that regardless of what search terms I the only hits are to partition skirting (and there are not many of those).

Black glass Tufnol sounds interesting, presumably, even though black its RF properties would be OK, the control unit has an 868MHz transmitter and a 433MHz receiver (common low power remote control frequencies).

Ian P

I've not come across Trespa but it might be suitable, 3mm seems thin on the ground. One thing I noticed on the descriptions in the website Rod linked to was this statement

'Keep in mind that HPL expands or shrinks faster than other plastic panels' !!!

Ian P

Did the material you used have a name?

Seems odd that the only known use of this material is for skirting. It extremely heavy and dense and although I dont know all its properties its virtually incompressable and the 7"x2" oddment I have hardly flexes when I try to bend it using hand pressure. 1.5mm mild steel the same size/force would be permanently bent.

The intention is to engrave and fill but its only a few characters per panel so not a problem.

Ian P

I did see that on my searches yesterday and was planning to phone on Monday and ask what the material is. With it being described as 'laminate' I thought it might be of laminated construction and not homogeneous.

I need to make 20-30 panels about 240mm square so I need to find 8x4 sheets or whatever 8x4.

Its for equipment used in tropical climes and needs to be transparent to radio frequencies so metal is out. 3mm is about the maximum we can use and not many plastics are stiff enough (push button and other controls mounted on it) Acetal is too floppy and too shiny, rigid PVC is too soft, Paxolin, Tufnol etc are either wrong colours or too expensive hence looking for this skirting stuff.

Ian P

About 20 years ago I purchased 150mm wide and 2.4m long strips of a very hard laminate type material that was used as a kick strip/skirting as one of the elements in the office partitioning industry.

The company I bought it have moved or disappeared and I'm struggling to find any reference to any sources.

The scrap bit I have is very much like Formica but apart from being much thicker seems to be homogenous solid black all the way through. The front surface has a very fine satin brushed finish and its rear face has the coarse brushed finish seen on the underside of kitchen laminates. Physically its very hard and rigid, wears out drill and cutters rapidly and gives off a phenolic like smell.

Does anyone know what it is and whether its still available?

Ian P

PS The odour when machining is like burnt Bakelite

Edited By Ian P on 13/06/2021 16:24:44

That would be perfect if it was in stock. I've trawled all the PC cooling fraternity and a few list that same tube, but none have any stock.

1mm in pgk2's link will be suitable so thanks.

Ian P

I need about 20 pieces 50mm long of 14mm OD tube with a minimum bore of 12mm. I have not found any UK suppliers with 1mm wall but there are some that list 1.5mm wall but none seem to have stock.

In my searching I discovered that SS 14x1mm was quite common until recently as it was used by gamers for the water piping in PC cooling systems, nowadays though its been replaced by rigid plastic tube (its cheaper? but its best feature is the colour choice!

I could make the parts I need on the lathe but chopping tube (using a plumbers pipe cutter) will give me nice radiused ends.

Has anyone got any surplus PC tubing I could buy?

Ian P

Purist might complain, but I would think that 1/4" UNC might be a lot easier to find and will hold the chuck in place.

Whitworth threaded fasteners are a getting rarer and rarer and certainly not used in new designs, whereas UN fasteners and threads are used in current production in some countries (well the USA at least)

Ian P

My hero!

Ian P

I absolutely 100% endorse what Robert Atkinson-2 wrote above!

More information about the equipment itself would help us suggest how it could be made safe to use, questions that occur to me include,

What temperature does it operate at?

Is it temperature controlled?

If so, do each of the ali blocks each have their own temp sensor?

Are the two block held in some mechanical jig, hinged frame etc, or do they just bolt together in use?

Whilst the wiring and accessory bits visible are designed to be heat resisting, we can also see nylon cable ties which do not seem to have been melted/overheated, so maybe the operating temperature is no so high?

Fastening terminal blocks or other parts to a plate on short standoff spacers would greatly reduce their temperature and probably make assembly and wiring easier and be something perforated protective enclosures could be attached to.

It does not look like this equipment is a commercial product as it certainly should not be on the market as it is. I have in the come across products with mains cables with just a knot and grommet (and choc-block) terminals stuck down with hot-melt glue. Nowadays fortunately we have better regulations, CE and other certifications.

Ian P

The head may move down (an almost immeasurable amount) until the point that the countersinking cutter touches the job and then the head will (try to) move upwards as a reaction against the downward movement of the quill.

Ian P

Demurrers might be, but cutters are more 'snail' shape