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Member postings for colin hawes

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

Thread: Churchill Cub Lathe
07/03/2012 20:52:03

I would not advise hitting the chuck key.Use an an adjustable spanner on one of the jaws instead or preferably, if possible, grip a long bar across the jaws and use it to get real leverage. Colin

Thread: Long drills?
27/02/2012 17:57:05

A drill can be soft soldered (sweated) into a mild steel rod to extend it. Just drill a hole about five diameters deep with a standard drill, clean the drill shank with emery cloth, make sure there is no oil on the parts, and ,using Bakers fluid flux, tin both parts.Heat both parts with a blowtorch and twist together to ensure complete coverage of solder. This joint is strong enough for any drill that you are likely to use and can be used on taps too; also it is easy to dismantle. Colin

Thread: Milling machine stops
27/02/2012 17:18:02

If you need accuracy with stops you can use a fag paper to get a good feel.When the paper is just nipped you are there. Colin.

Thread: Thread forming taps
27/02/2012 17:08:28

Thread forming taps are best for ductile metals, especially copper and soft aluminium, in sheet form .They are stronger than fluted taps and are usually used for machine tapping. Not suitable for tapping castings.As they work by deforming the metal a stronger thread should be produced Note the different hole size and lubrication required. Colin.

Thread: Whistling Cutter
16/02/2012 15:27:17

Slower speed , less cutting depth, coolant and heavy-ish feedrate gives best results when using HSS cutters on tool steels. As Andrew says, allowing the cutter to run on the work without a good feed rate can quickly blunt it. The cutter must be kept sharp.Wear on it's diameter is fatal on toolsteel. HSS is perfectly satisfactory on toolsteel if these guidelines are followed Colin.

Thread: Problems machining brass - Bad finish !
16/02/2012 15:10:29

The tool is not sharp enough or lacks clearance. Colin

Thread: Opus die filer
16/02/2012 15:02:37

I used a Thiel die filer in my apprentice days.It used special files with a plain section at both ends for gripping. The filer was mainly used for adding relief to the press tool dies.It can be a very useful machine. Colin

Thread: Magnetic chucks on lathes
16/02/2012 14:51:26

I have used double sided tape to hold shims for skimming to a thinner size. Can only take max 2 thou cut though using a sharp tool.With a magnetic chuck I would have thought magnetic swarf could be a problem.You could ,of course, hold brass etc. using double sided sticky tape.


Thread: 3 - Jaw chuck on Clarke 300 lathe / cutting speeds for brass / steel.
13/02/2012 16:17:33
The speed for cutting a metal bar depends on its diameter and material.Also the rigidity of the machine. Using HSS tools on mild steel ,about 700 rpm would be ok for 3/8" to 3/4 dia 500 rpm up to1" dia but cutting the larger sizes you should use a cutting fluid of some sort to maintain tool life and finish. 50% higher speeds for brass and aluminium. Note that, without lubrication, aluminium tends to weld itself to the tool causing a torn finish. Smaller diameters will be cut at proportionally higher speeds. I hope this gives you a good starting point! Of course ,you can't achieve ideal speeds when facing the end of a bar because its diameter is not constant.
Thread: What cutting tools for mini - lathe (HSS or Carbide Tipped ?)
13/02/2012 15:35:40
Don't get bogged down with "recommended rake angles" my experience indicates you are better off with more rake for non heavy- production work the recommended figures are designed to allow the heaviest possible metal removal with best tool strength and heat dissipation. Our hobby does not create such conditions.Your tools will give a better performance with lots of rake, like a slicing knife rather than a hammer and chisel Try it.
13/02/2012 13:21:40
hi Chris: I recommend starting with HSS tools as these are more than adequate for your application. Tipped tools are expensive to buy and use and offer little advantage on most machining operations, the exception being cast iron if you want to remove metal quickly or if it has commonly found hard spots in it.Stainless steel comes in many grades and i'm assuming you intend to use a free-machining type.HSS tools should be kept razor sharp so touch them up on the grinder before you start a job ,making sure you have plenty of rake on all cutting faces and a good finish should be attained on the workpiece.Industrial machining is done with tipped tools to get very fast metal removal with minimum tool wear and the best results are attained on very rigid and powerful machines
Thread: What size do i drill a brass cylinder in order to ream it 5/16 "
11/02/2012 16:25:36
The amount a reamer should take out varies wih its diameter, about 5 thou for small ones eg. 1/8"dia , 8 thou up to 3/8" and 8 to 12 thou above that .The drilled hole has to be a reasonable finish and should be done with an undersized drill first then opened up with the reaming size drill.Reamers over 5/8" dia should be o.k. at 1/64" undersize hole.As with all cutting tools, the reamer needs to be sharp.
Thread: Fine Finish on Crankshaft
11/02/2012 15:56:41
I agree that a sharpened HSS tool will produce a better finish in this instance provided it is ground with a good rake in all cutting directions.Hard-tip tools are ,in my opinion, very much overrated for use on most materials used in our hobby.Cast iron is the most likely metal give you the benefits of carbide tips .HSS tools are easy to sharpen and that is most important for a good finish.
Thread: Countershaft pulleys for Grayson lathe
31/01/2012 19:04:37
I made flat belt countershaft pulleys for my lathe and horizontal mill using 1/8 steel sheet rolled and welded .They have been going for 40 years with no trouble.
31/01/2012 19:04:34
I made flat belt countershaft pulleys for my lathe and horizontal mill using 1/8 steel sheet rolled and welded .They have been going for 40 years with no trouble.
Thread: Myford Lathe Problem
28/01/2012 17:23:16
Idon't have experience of the Myford,but it is not uncommon for the dial to be fitted with a spring- loaded ball for friction.This ball can be lost on dismantling.
Thread: Steel boiler for 5" loco
28/01/2012 17:15:22
There are regulations that will make it very difficult for an amateur to manufacture a welded steel You have to be able to prove competance at welding, you have to use the correct grade of steel which is certified,you need to produce test welds for inspection,and it it has to be examined during construction.I don't know about rivetted steel boilers. If it is for a small scale such as 5" the required thickness of steel is likely to make it impractical.
Thread: Issue 4422
28/01/2012 16:57:22
It seems to me that a flat belt stays on a convex pulley simply because it is forced to stretch to a longer length at the middle of its width than at the edges,a bit like wearing in a new pair of shoes ,so the edges of the belt being shorter than the crown means they don't easily slide across the crowned pullies.
Thread: gland nuts
28/01/2012 13:19:57
I agree with John,the answers "yes".
Thread: Manky External Threads
26/01/2012 18:00:31
A blunt die can sometimes be sharpened with a Dremmel type grinder if it has not been used for too long in a blunt state.
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