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Member postings for HOWARDT

Here is a list of all the postings HOWARDT has made in our forums. Click on a thread name to jump to the thread.

Thread: Advice from the photographers.
22/10/2021 19:59:48

There are lots of options, such as macro lens or extension tubes etc. I have a flat bed scanner and software that allows me to copy multiple slides at once, but it all takes a tremendous amount of time and every capture has to be edited to get the best out of them. If you have a projector you can use that and photograph the projected image. I have been copying my family negatives and photos for some time and am nowhere near finished, probably a project for my kids to finish when I am gone. If you really value the images then get them copied professionally using a continuous feed and copy system.

Thread: Ball screws
13/10/2021 16:44:21

With ball screws you have to take both the nut and the screw design into consideration. Obviously the best would be a ground screw with a double nut, the screw can have the greatest pitch/travel accuracy and the nut balls are selected to give the best fit with the double nudt reducing backlash to a minimum.

In machine design I used to use ground ball screws, but eventually these were replace by rolled screws and software position compensation. But this was all with proper servos and dedicated software.

No doubt there is someone here that can answer your question from experience of what you want to do. Price will be the final answer, but think about what you are trying to achieve positional tolerance wise and can you measure that. I am sure like the rest of us you don't have a temperature controlled CMM.

On a Z axis you will benefit from some sort of counterbalance, so you may well get away with a smaller screw size.. A hydraulic strut system would work, the final machines I designed had hydraulic cylinder systems.

Thread: Warco GH Universal mill help
23/09/2021 09:18:36

I also have a GH Universal and have looked at the same problem. The motorised version uses a 120W geared motor driving the screw from the top of the column. Not sure what the ratio is on the gearbox but various versions are available on Amazon. When I designed vertical slides they where mostly balanced by a hydraulic cylinder fixed directly to the slide but these catered for full safety on failure, so in our case a gas strut would be ok. One day I will get round to doing it but at the moment I can live with the handle.

Thread: Piston rings
18/09/2021 16:29:49

Assuming you cylinder is bronze and not cast iron then a single o ring should be ok. Just select the correct material for the o ring, not standard epdm. Surface finish should be honed to a fine smooth finish. Only a single o ring should be fitted in order for the ring to be adequately lubricated in both directions of travel.

If the cylinder is cast iron then iron rings should be fitted, the reason being surface finish and rusting will cause early failure of a rubber ring. Yes rubber seals are used in brake cylinders etc of cast iron but they are in the presence of lubricants only. A very good YouTube video has just been put up by MrCrispin on cylinder rings, well worth a watch. I am sure some will have a lot to say on the subject, but that is my take.

Thread: Ideas on how to make up a G-Clamp Swivel Foot
18/09/2021 13:44:59

You could put a saw cut across the socket to make crimping easier.

Thread: How do you make this
17/09/2021 18:11:56

You could either machine from one piece using offset centres to turn the part or create one eccentric with the boss and through hole, with another eccentric which can be fixed to the first with the correct angular position.

Thread: Leadscrews and other features of Asian milling machines
16/09/2021 16:52:35

As said if you have dro you won’t look at dials. It is quite normal to have one ground and one scraped surface, ground surface is often hard so can’t be scraped. The scraping as said is to create a relieved surface to create oil pockets after first grinding, also used to correct geometrical errors.

Thread: Workholding Problem
11/09/2021 21:24:39

Machine the thin large diameter to a known size and clamp it into a shallow pot on the rotary table, then create the drive dogs. Doing it this way you can turn your diameters in one setup for concentricity then clock on the table if looking for better accuracy of slot position.

Thread: Milling machine coolant system
11/09/2021 19:07:25

You have to take the amount of enclosure the machine has. A cnc machine uses high pressure coolant, any thing up to 1000’s psi, and these are fully enclosed, any other type of enclosure will limit your pressure and flow unless you work ina wet suit with breathing gear. For aluminium you are probably better stick with air to blow the chips clear and a small amount of lubricant directed to the cutting edge. Another way is to create a cold atmosphere at the cutting edge which will break the chips earlier stopping edge weld.

Thread: Gun Laying Plotter Instrument ?? OZALID
09/09/2021 15:53:12

As a drawing office apprentice we all had to take alternate weeks in the print room. The worse job was replacing the gallon bottle of ammonia in the print machine. Quite a few times it would get tipped over filling the office with fumes. That added to the bottles acetone and trichloroethylene that we used to clear print areas on plastic film prints made for a very healthy atmosphere,oh yes and the smoking.

Thread: Not a master mechanic
04/09/2021 13:23:59

I find that annoying when you want to see how something is done, when they say what they are going to do then voila done. It is worst than those who show the whole thing with every move, at least then you can fast forward to skip to the next interesting bit. I have watched pieces of some YouTube machinists where they show every tenth of a millimetre cut, when all I am interested in is the setup, perhaps one cut then the final result. Yes I prefer Ed as well.

Thread: Tightening a Threaded Bolt
01/09/2021 19:50:47

Cast iron and steel do form a slightly corrosive interface. To some extent both will deteriorate. If you do fit a helicoil ensure it is correct for a through hole.

Thread: Whirlpool cooker
01/09/2021 19:47:39

A few years ago my oven failed about five days before Christmas. It was still under the manufactures warranty and the model had a inherent fault, it had a pyrolitic self cleaning oven which failed. Ended up cooking the turkey at my fathers, twelve miles away, the day before. Got a replacement model in the new year, which had to then be replaced as they sent the wrong one. Took six months for them to get it all sorted.

Thread: Maching O ring grooves
01/09/2021 16:38:34

Piston diameter should be calculated to give a specified clearance between the bore, depending on ring compression and surface speed according to the o-ring hardness and material. Smaller diameter rings can be stretched to achieve a better running fit and the groove calculated to suit. I have modified o ring designs go from impossible to move go to freely move and still do the job they were intended for. Perhaps get a few extra rings and do some experimentation to find what works in practice. Manufacturers data is a catch all set of figures, when you talk to them about a particular application they will come up with a different set of figures to the basic data.

Thread: Stanley combination plane
30/08/2021 13:16:51

I had a collection of wood working tools including a number of Stanley and Record planes some with the odd screw missing. After some research I found a set of assorted screws and wheels for sale on Amazon. They didn’t all fit my requirements but I was able to complete the missing parts with a little work. I think the thread I wanted was 3/16” BSW or F and the parts were less than a set of taps and die which seem to be in rather short supply.

Thread: Coolant pump - how to slow flow rate?
29/08/2021 17:52:48

+1 - Fit bypass valve back to tank, restricting flow causes cavitation at the impeller.

Thread: Is there any benefit to copper plating before nickel plating?
29/08/2021 17:47:53

I remember years ago visiting the Premier Drum factory and seeing their electroplating system. All their metal plating was done in house with copper being the base layer. Their finish was impressive after much hand polishing both prior and after plating.

Thread: Purpose of screw on keyway
29/08/2021 13:25:56

Keys are usually defined as side fitting, therefore the screw stops the key from lifting. That is supposing all the sizes are to the standards.

Thread: To Cap It All
28/08/2021 14:00:58

Why not try ringing a radiator refurbished/maker, I have one near to me and there was one recently on a car rebuild program recently.

Thread: Hoglet Kick Starter
24/08/2021 13:00:49

Search for sprag clutch bearing. Simply Bearings appear to have a few.

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