Member postings for colin hawes

BSP 28 tpi threads come close. Colin

Edited By colin hawes on 27/08/2019 15:42:11

I have a cheap 3 jaw chuck that is quite accurate on some diameters of stock and much less on others, the accuracy varying between 0.001" and 0.005" T.I.R. Having checked the parallelism between register, back plate and chuck faces I come to the conclusion that the scroll is likely to be the cause of the variation so it seems that for one-offs I might as well use an independent four jaw chuck as attempt to adjust the self centering one...……I am hoping to improve things now that I have discovered small burrs on the scroll Colin.

The scroll needs to be checked for radial slackness.

Edited By colin hawes on 06/08/2019 10:33:04

Be wary of the description HSS. It's been used as a suppliers name in the past. Colin

Estimation followed by adjustment if necessary. Colin

If I am doing intricate work I tidy all around that area first otherwise something is certain to disappear but I do keep the machine surfaces wiped clean. I do the floor if I think it needs it. Colin

A company where I worked had frequent trouble with a radial drill motor randomly blowing one or more of it's three fuses. Electrical maintenance people were called in several times to solve the problem, checking everything with their test equipment and finding no fault as the motor would always run again with replacement fuses and their conclusion was that a rewind was required. I took the motor apart myself ( with some difficulty) and found the stator and rotor almost seized with accumulated sticky debris from years of use. It ran faultlessly after that was cleaned off.

Excellent training film. Colin

Yes....and make sure you keep the tools sharp. Colin

I don't know the exact design of this machine but the sort of things I would examine are : can the half nuts move? are there missing teeth in the gears? Has the shear pin partly failed? I would not expect end float on the leadscrew to be the cause of your problem. Colin

I have machined 24 notches on my backplate for dividing purposes. Colin

Thank you Ketan for that information. Colin

Does the control board have no overcurrent / overload protection then? Just a question . Colin

I have always reckoned that gears should be unbreakable not fail safe and that plastic of any sort for this job is used because it is far cheaper to injection mould a plastic gear than to machine a steel one. A sheer pin device would be used if protection was considered necessary but I have known a Tufnol gear to be used in a gear train to reduce noise. If my minimill gears ever strip I shall replace them with steel/cast iron ones and grease them well. Colin.

When I say deform I mean continually bend to wedge in its groove not wear; after all, the belt has to continually deform to go round the pullies. I have never seen the Hardinge drive but I guess it consists of interlocking pulley sides which must be hard on a belt anyway especially if the sector edges wear to be sharper. I don't claim to be any sort of expert on drive belts but just giving my thoughts as requested. Colin

I would expect the belt to deform that one degree to seat in it's pullies after a running in period.

This sort of destruction is completely beyond my understanding and I like to think I can understand most things. We see the same sort of destructive attitude to flower displays and newly planted trees in parks when real humans think they are lovely and would like more. Wanton destruction should attract a long and very visible hard labour sentence of benefit to the community.

My sympathy goes out to the club.

I use a Warco bandsaw for soft metals and mild steel and an angle grinder with 1mm cut-off grinding wheel for tougher steels (to save the saw blade) Colin

I bought LED 14W bulbs from ASDA. They give a light output like the 100W filament bulb. Colin

A hinged and latched notice board fixed to the ceiling could be a space saving way of hanging a drawing for those of us whose neck objects to looking up too long. Colin

The cutting speeds can be wildly different to the theoretical but generally the speed can be set by what the tool temperature and the machine can withstand; the feed rate can be increased with speed up to that limitation, for example, we often use far to slow a speed to cut screw threads because we can't handle the feed rate. The same applies to facing large discs where we need to consider the largest diameter although the speed is really too slow at the smallest diameter when you have no facility to continuously change the speed. By "feel" you can increase the feed rate as the surface speed increases. Colin