Member postings for GoCreate

Hi Stephen

I've built the Allchin in 3 inch scale. When driving the differential gears only rotate against one another when cornering and the rotational speeds are very slow. With this in mind, right or wrong, this is what I did.

I made my gear pinions from steel, to provide a good bearing I lined them with a cast iron bush and used silver steel pins, I coated the pins in dry film moly disulphide lubricant. On reflection an oilite bush could have been a better choice.

I also coated the gear teeth in dry film moly disulphide lubricant so no grease or oil is used.

I have only recently finished the engine and won't be steaming until next spring, so at present i can't give any feed back on this method.

Hope this helps.

Nigel

Hi David

I just use part of the radius of a ball nose end mil/slot drill of which I have several sizes. I just eyeball the cutter position to get what looks like a 45 deg chamfer of the required width. Although mostly I would just file it.

Nigel

Nick, thanks for the additional information.

I'm thinking ISO 220 will be a good all round choice for the ball screws + vertical and horizontal slides using a one shot lubrication system.

I can keep most of the lubrication pipework internal to the mill avoiding lots of external pipes, should be a neat solution. I have ordered the ARC one shot lubrication pump.

Thanks again

Nigel

Thanks for all your very quick replies

That's clear cut then, I wiil include the ball screws within my one shot lubricating system so they will be lubricated along with tte slideways using ISO 68 oil. I may follow Nick's suggestion and use ISO 220 for everything.

Involute Curve - yes, I will be ordering the ARC lubricating system.

Much appreciated.

Nigel

Edited By tractionengine42 on 17/07/2016 16:26:10

Hi

I'm converting a mill to CNC and using 16 dia X 5 pitch C7 rolled ball screws.

Any recommendations for ball screw lubrication?

A Google search does not give a conclusive answer, in general for hobby use it appears to come down to either use slideway oil iso 68 or general purpose lithium grease.

It appears moly or PTFE additives should be avoided as these friction reducing agents can cause the balls to slip or skid.

I am including a one shot lubricating system and I'm at the stage as to whether or not to include the ball screws, or alternatively, lubricate them separately using grease.

Any comment, experiences appreciated.

Thanks

Nigel

Hi Douglas

I had the same problem using the straight cup grinding wheel that was supplied with the kit, it's not normal and suggests the wheel is not suitable for HSS. My guess is the wheel is more suited to carbon steel tools.

I got a recommended wheel from a local supplier which worked significantly better, unfortunately I don't have the wheel spec and now use diamond wheels on my T & C grinder.

It's worth contacting a supplier for a recommendation, this link may help is selecting a suitable wheel. Look under cutter grinding/HSS.

Regards

Nigel

Edited By tractionengine42 on 27/06/2016 09:19:57

Hi

Here is another website to consider. Don't forget customs will charge the 20% vat plus a handling fee.

Nigel

Often the ends of Rebar is bent as a requirement of the final structure so needs some ductility and therefore presumably will have some impact strength.

https://youtu.be/4ecZrrEtlpY

https://youtu.be/4ecZrrEtlpY

Nigel

Edited By tractionengine42 on 18/02/2016 17:04:05

Yes, Dorian tools Inc

Clearly there are various types of carbide boring bars and recommendations from various manufacturers.

Of course these recommendations are relative to an industrial setting where production rate and tool performance are paramount. Maybe not so relevant in a home workshop however, the OP does report some observed benefits of his set up thus it's worth consideration.

Nigel

Nigel

Hi Steve

Regarding the gear train noise I fitted 2 timing belts as shown in the photo below. With this arrangement rotation of the Banjo to disengage the gears from the spindle drive allows engagement of the timing belts and vise versa. The intermediate gears are also moved along the banjo slot to dis-engage with the final driven gear.

I use the time belts for normal feed, for screw cutting it's a quick changeover to engage the gears and dis-engage the timing belts.

I did this mod 10 years ago and it's worked without any problem.

Additionaly the time belt is arranged to give finer feeds as compared to using the gears.

For the carriage lock I used an indexable lever.

Nigel

Hi

I have my Elliott Omnimill standing on polypropylene interlocking tiles without any problems although I do have a sheet of 12 mm ply between the machine and floor.

That said it would definitely be preferable to stand the machines on the concrete, especislly the lathe which will require some levelling adjustment when being set up.

Nigel

Thanks Jason

Andrew did pm me with some details.

I have contacted the advertiser on here with an offer but as I am working in Singapore for the next few weeks I can't collect any purchase until December

Much appreciated

Nigel

Hi Roy

From Quingdao Port, China to Aberdeenshire.

Tormach website says they can arrange freight or I can arrange myself. I've not made any enquiries yet, I'm interested in what others experiences are and what they would recommend.

Thanks

Nigel

Edited By tractionengine42 on 02/11/2015 15:04:53

Hi

For those with experience importing a Tormach pcnc mill, any recommended does and don'ts, any rough idea what freight cost I could expect?

Thanks

Nigel

I bought one of these but haven't installed it yet so can't say how reliable it is.

Nigel

After my ME paper subscription ended I subscribed to the digital edition last week, an email advised my subscription number will be sent by post, that was disappointing, I expected almost immediate access, but I still haven't received it.

My MEW paper subscription ends in 2016, but I have not received the last edition.

I had not realised there was to be a change in the subscription provider, I guess I will give it a week to let things settle down in the hope it will sort it's self out.

Hi Mick

Here's some pictures of the clapper box I have, It's 4" long x 2-3/4" wide. Its got surface rust though I think it will clean up nicely. Please send me a PM if you want it and I will find out the postage cost.

There is some play on the pin, probably this will need replacing and the through hole trued up, the pin measures 7/16" parallel so could be made 12mm.

Nigel

Edited By tractionengine42 on 29/08/2015 18:36:35

Hi

I've just completed a mod on my I/2 " BSW draw bar to accept arbours with M12, M10 and 3/8 BSW.

My captive draw bar is easy to remove, so I cut the end off and drilled and tapped it M8, then I made adapters to screw in. The pics show the before and after.

This does require the draw bar to be removed each time a different threaded arbour is used, If that's not acceptable then the same mod could be done but with the adaptors made to screw tight into the arbour, just provide a flange to tighten up against.

I did notice some arbours require a longer draw bar by 3/4"

Nigel

Hi

I though the following might be of interest as it's relevant to torque tightening.

Torque wrench calibration is one thing but out of calibration tools are not the main source of error when tightening a bolt to a pre defined load.

A higher proportion of the torque value is needed to overcome friction between the mating threads and the underside of the nut in contact with the joint/washer known as the Spot face. This friction has to be known/controlled to get close to a predefined bolt load. This friction can be controlled by using a suitable lubricant or anti-seize compound.

Therefore, a specified torque value should always be accompanied with the lubricant to be used.

For example:

M12 grade 10.9 bolt to be torque tightened to a bolt load of 70kN.

Using KS Paul Easyrun 100 (low co-efficient of friction lubricant) Torque value = 98Nm to achieve 70kN bolt load

Using KS Paul PBC (higher co-efficient of friction lubricant) Torque value = 167Nm to achieve 70 kN bolt load

For this example I have chosen to commonly used lubricants used in industry that are at the opposite ends of the co-efficient of friction scale. It can be seen that if you were given a torque value of 167 Nm but used Easyrun 100 to lubricate the threads and nut spot face you would dangerously overload the bolt. Vice-versa will apply resulting in a bolt seriously under loaded bolt and perhaps subject to eventual failure due to fatigue under cyclic loading.

To summarise, a torque value without a specified lubricant is meaningless and therefore, so will be the torque wrench calibration. The correct bolt preparation is an essential part of the process.

Here's a youtube video

Nigel