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Member postings for Kevin D

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

Thread: Removing Broken Tap
30/06/2019 16:03:10

I have had great success using a phosphoric acid solution for rust removal. Fill up the space between tap and s/steel with un diluted acid. Wash out once or twice a day and replace til the remainder of the tap falls out. Not fast but no damage to hours of machining work . Mine was a M4 tap. Always use a new or very sharp tap.

Thread: Building a Belt grinder - advice please.
25/04/2019 12:28:26

Hi. Have built a 4 x 36" with a 750w motor. It used a rotor and bearings from an old motor as a drive roller with a 8" disk on the end. Belt drive with idle pully to tension. Works in either vertical or horizontal position.

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Thread: Soba rotary table
12/03/2019 11:42:55

I purchased 6" soba table some years ago from a well known UK supplier. It failed and needed a new worm wheel. I was advised that part HVRT-03 was not available. A supplier here in Australia had a table that looked the same and could get a gear for $98 AU. Now the good news. They had a sale on the next week and a 6" vertex was $180. The soba dividing plates and tail stock will fit it.smiley

The reason for the failure was having too much or any back lash while milling 16mm cooling channels in a 300dia Al plate. The worm gear is soft cast iron spur gear cut at about 1.5 degree helix angle (not a worm wheel). It had teeth missing in more than one place around it. Now the fix. A small amount of grinding with a burr to clean up any high spots in the table body and a spacer to go between the table top and the gear. The gear now hangs lower just clearing the inside and the worm bears higher up on an undamaged part of the gear. It now work fine.

Any heavy load on these gears will cause damage.

Thread: WHERE ARE THE SHAPER USERS ?
11/02/2019 06:56:48

Hi Rod.

I had the same after rebuilding my 10m. I fitted a teflon washer behind the scale on the cross feed screw and a fiber washer behind the nut and washer on the adjustment end. Slight drag with no back lash. It may show in pic's on my album. The big mod's were to the oiling system. A common reservoir for the 4 oilers on the back with 1/4" air line fittings connecting them. The ram and crank oilers were replaced with 1/4" and 3/8" flare refrigeration fittings with caps. A visible and ample reservoir to fill with oil.

The 10m was stripped to small parts and transported home to the top of a very steep driveway in the boot of a car. My son asked while struggling to help carry the main body casting, what would I do with it. Answer, use it till I fell off the perch, then it would be his problem to get it back down the hill.

Kevin

Thread: Hi from Australia, Pick a subject for next post
23/11/2018 11:30:39

Hi Perko7. The primary oil sealed rotary vane pump does back stream oil vapour at ultimate vacuum. Hot pump internals cause oil vapour to travel through the vacuum and out the inlet against the pump flow direction. The good vacuum oil is highly refined without colour or smell. No smell equals a very low vapour pressure. The back streaming can be stopped by an activated alumina trap or a cryo trap (liquid nitrogen). Pump clearance is about 5 thou. High vacuum systems usually have a second pump stage of a turbo (electric powered jet turbine), Diffusion ( a stream of silicon vapour drags gas molecules to exhaust) or cryo (freezes and traps gas on panels to lower pressure). Regards Kevin

23/11/2018 11:06:46

Hi Bob. I like the way you have found something of limited value and converted it to a valuable and useful workshop tool. A friend used to laugh when I told him I could see an improved watsit hidden in a large lump of scrap. It is an art form that we should all value. Keep up the good work.

Regards Kevin

Thread: New Mill - Starter Tooling
21/11/2018 13:04:06

Hi Ron

Did I see a 50mm boring head on the mill table? Machine up an adapter to fit it and use a broken HSS tap shank for the cutting tool. The cheap and quick solution will leave more time for projects. Keep it sharp and do not overload the head.

Thread: A fine parting tool
21/11/2018 12:45:03

A HSS broken cutting saw blade was begging for a second life. Taper groung faces 80dia. x 1.6 thick HSS Co5% used for cutting s/s tube. When ground it gives about 10mm cutting depth. The first design has the blade center 1mm below lathe center height. It allows the blade to be rotated up to tool center and gives some top rake.The next design will only have 0.5mm below. This would avoid excessive grinding to obtain front clearance. If it digs in it rotates down and away from work. Great for circlip and oring grooves.p9030199.jpg p9030201.jpgp9030202.jpgp9030200.jpg

Thread: Hi from Australia, Pick a subject for next post
21/11/2018 12:21:31

Hi Perko7

High vacuum is mostly used in laboratories. In the range of one millionth of an atmosphere or less. This pressure is low enough to evaporate the oil in a finger print. Common in mass spectrometer and electron microscope's. Primary pumps being rotary vane, diaphragm, scroll, sliding piston etc. Secondary pumps being turbo molecular, diffusion, cryogenic etc. I have manufactured parts and systems for vacuum coating, some automation programming and lots of design work.

Thread: Milling machine to cutter grinder and 4 facet jig.
21/11/2018 09:06:41

Second part.

The 4 facet jig is base on Les Riley's design (MEW Feb 2006). The body 110dia by 80 long steel. This was welded to a short piece of 3" channel at an angle of 59deg. img_0080.jpg

img_0083.jpg

img_0085.jpg

Mount in a 4 jaw and machine the angled face, bore 25dia. at an angle of 31deg. Cut off channel and dress outside, dress base and leave a small spigot to locate centre. The 6x6 groove allows clamps like those on the rotary tables. Now a few hours on the shaper to cut each side. The ER32 collet chuck with a 25 dia parallel shank has two flats on the body. A perfect location to give 180 deg rotation, an aluminium clamping plate locates on the flats. The clamping plate also has a surface at 22.5deg. on the other side. Reverse the plate to get the rotation for the sixth facet. img_0832.jpg

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A M3 holder was machined up with a 25die shank for large drills. This has pin location similar to the original design.

The base was a cast iron pipe flange, the locating spigot was machined to give table slot location.

And now a question. At what size do you have to change to 6 facets. I am still having some fun getting parallel primary facets. This must be due to the drill rotated slightly off vertical cutting edges in the jig.

All the parts were modeled on Varicad 3D prior to machining. I have uploaded most of the photo's, look in the album's for more.

21/11/2018 09:02:37

Had this on the end of my first post. Should have started a new one.

Thank you for your reply's. Please be patient the photo's to still be uploaded are post production.

I will combine the old mill conversion with the 4 facet grinding jig. The old mill was picked up at auction some time ago. M3 spindle on large taper roller bearings with a belt drive. The spindle head is on a vertical dovetail slide with a rack and pinion to raise and lower. A fine 3/8"bsf thread for spindle height / depth stop. p3100286.jpg

The height over table was limited, so the pillar holding the knee adjusting nut was shortened. New acme table nuts were cut on the lathe. The old ones had worn to a whitworth profile. New lead screws made and the table re ground. As a mill using M3 collets it was very average. Lots of pounding on the draw bar to release the collets. Have use R8 ever since.

A 50mm dia grinding spindle was made using taper roller bearings. Ref Workshop practice series No27. The original idea was to use a cheap Aldi 5" grinder to power it. After removing the gaiter springs from the oil seal each end it was still puffing and panting. More power was needed. A cheap pistol drill came to service. A flat belt pully was made to screw on instead of the chuck and the drill mounted by the universal round boss behind the chuck. Back to the mill. Remove the spindle and inner parts of the roller bearings. This leave two opposing tapered seats orientated vertical to the table with raise and lower movement and depth stop.

A block of aluminium was bored 50mm for the spindle. At right angle to this a post with a male taper seat to match the bottom taper roller outer shell. A second taper seat was made to seat in top bearing shell. This gave a horizontal spindle which could be rotated about the vertical axis to a limited extent. img_0801.jpg

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img_0803.jpg

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The spindle is hollow with an ER32 socket and flat belt drive. The grinding wheels are mounted to the spindle in a similar manner to a Quorn, except an ER32 taper size in aluminium with a m10 draw bar is used. This allows the spindle to use wheels or cutters mounted in collets. img_0806.jpg

The wheel is raised and lowered to grind with the x axis used to increase cut. Now this is good for the 4 facet jig. Cut one face and raise the wheel. Rotate 180 deg. and cut the other face without changing the table position. img_0808.jpg

This may upset some readers but, I have a number of wheel mounts with worn angle grinder cutting disks. Cheap and quite ok for gear cutter grinding, the thin 1mm thick disks flex a lot, the 3mm ones are better. As the wheel moves at right angles to it's rotating axis the cut is on the outer edge.

Thread: Hi from Australia, Pick a subject for next post
20/11/2018 12:48:32

Thank you for your reply's. Please be patient the photo's to still be uploaded are post production.

I will combine the old mill conversion with the 4 facet grinding jig. The old mill was picked up at auction some time ago. M3 spindle on large taper roller bearings with a belt drive. The spindle head is on a vertical dovetail slide with a rack and pinion to raise and lower. A fine 3/8"bsf thread for spindle height / depth stop. The height over table was limited, so the pillar holding the knee adjusting nut was shortened. New acme table nuts were cut on the lathe. The old ones had worn to a whitworth profile. New lead screws made and the table re ground. As a mill using M3 collets it was very average. Lots of pounding on the draw bar to release the collets. Have use R8 ever since.

A 50mm dia grinding spindle was made using taper roller bearings. Ref Workshop practice series No27. The original idea was to use a cheap Aldi 5" grinder to power it. After removing the gaiter springs from the oil seal each end it was still puffing and panting. More power was needed. A cheap pistol drill came to service. A flat belt pully was made to screw on instead of the chuck and the drill mounted by the universal round boss behind the chuck. Back to the mill. Remove the spindle and inner perts of the roller bearings. This leave two opposing tapered seats orientated vertical to the table with raise and lower movement and depth stop.

A block of aluminium was bored 50mm for the spindle. At right angle to this a post with a male taper seat to match the bottom taper roller outer shell. A second taper seat was made to seat in top bearing shell. This gave a horizontal spindle which could be rotated about the vertical axis to a limited extent. The spindle is hollow with an ER32 socket and flat belt drive. The grinding wheels are mounted to the spindle in a similar manner to a Quorn, except an ER32 taper size in aluminium with a m10 draw bar is used. This allows the spindle to use wheels or cutters mounted in collets. The wheel is raised and lowered to grind with the x axis used to increase cut. Now this is good for the 4 facet jig. Cut one face and raise the wheel. Rotate 180 deg. and cut the other face without changing the table position. This may upset some readers but, I have a number of wheel mounts with worn angle grinder cutting disks. Cheap and quite ok for gear cutter grinding, the thin 1mm thick disks flex a lot, the 3mm ones are better. As the wheel moves at right angles to it's rotating axis the cut is on the outer edge.

The 4 facet jig is base on Les Riley's design (MEW Feb 2006). The body 110dia by 80 long steel. This was welded to a short piece of 3" channel at an angle of 59deg. Mount in a 4 jaw and machine the angled face, bore 25dia. at an angle of 31deg. Cut off channel and dress outside and cut a 6 x 6 groove around base, dress base and leave a small spigot to locate centre. This allows clamps like those on the rotary tables. Now a few hours on the shaper to cut each side. The ER32 collet chuck with a 25 dia parallel shank has two flats on the body. A perfect location to give 180 deg rotation, an aluminium clamping plate locates on the flats. The clamping plate also has a surface at 22.5deg. on the other side. Reverse the plate to get the rotation for the sixth facet. A M3 holder was machined up with a 25die shank for large drills. This has pin location similar to the original design.

And now a question. At what size do you have to change to 6 facets. I am still having some fun getting parallel primary facets. This must be due to the drill rotated slightly off vertical cutting edges in the jig.

I will try to upload some photos tomorrow, this will give a clearer image to the text. All the parts were modeled on Varicad 3D prior to machining.

19/11/2018 13:16:13

I have enjoyed reading many posts, now I should share some of my good and bad experience. Please pick from the list where to start.

A tool post mounted spindle.

An old mill to a tool grinder.

Repair to a soba rotary table.

4 facet drill grinding jig

gear cutter grinding jig

3 axis DRO to RM45 mill.

Elliot 10M restoration.

I have a small engineering workshop specialising in high vacuum repairs.

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