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Member postings for Neil Lickfold

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

Thread: Effect of Tensioning a Boring Bar
07/02/2020 10:23:23

I can't do the math, but liken it to a plastic bag tube. Put pressure in it, and it is substantially more rigid than when the pressure drops, etc

Sandvik did boring bars with oil and a piston. As it is being used, (in a lathe) you can adjust the pressure and tune it to the situation it is in. I have not made one yet, am thinking about using it to fix a bar and see what happens.

When I get it done, will post the results here. The bar I am going to try has a 12mm diameter shank and a min bore diameter of 14mm. It would be great to be able to do the math t hing and figure out that if it has 120psi it becomes this rigid for example.

Neil

Thread: Superglue chucks
28/01/2020 08:57:04

Sometimes freezing can remove super glues as well. Tap it with a piece of wood and hammer while still frozen.

It just takes longer unless you have dry ice handy.

Neil

 

Edited By Neil Lickfold on 28/01/2020 08:57:44

27/01/2020 07:42:44

It depends on the super glue being used. There are higher temp super glues that will hold to about 150 c or so, and others can only hold to 100c to 110c.

Thread: Reamer specifications ?
20/01/2020 09:14:27

You can buy a standard tolerance reamer, and carefully lap the OD to make the closer tolerance hole. The better reamers I find are the ones that have un even flute distribution. For accurate holes, I pre bore with a undersize reground end mill or I make a single point cutter that effectively will bore the hole in the correct position. Then ream.

For important hole sizing, I make a test hole and measure it. Then if needed, lap the od some more and re test again. I am finding that the hss reamers that are readily available out here from the tool merchants, are on the upper limit of the H7, rather than lower limit.

Different cutting fluids etc will vary slightly the result , and so will the cutting allowance etc. Castor oil can make a hole smaller than the reamer, but only by 2 to 4 um. But is not absolute guarantee though. Castor oil will allow oversized parts to assemble that would other wise be a press fit. Down side, castor oil makes an ugly mess over time.

Some places that make carbide reamers, will often ask for a size limit or the size you want with the maximum and minimum size. Like a Ø4.494mm reamer with an upper limit of Ø4.496mm , these will cost like 60 to 70 pounds each like the example I gave .

Thread: Myford super 7
14/01/2020 09:09:01

I always use the clutch, unless screw cutting a thread. I use the motor switch and leave the 1/2 nut engaged. Now that I have a programmable VFD, the start is softer and the stop is softer as well. Another advantage of the VFD is the ability to slow down the spindle before turning off, very helpful with the odd large work piece. With the clutch, you can also slowly engage or disengage on large work pieces.

Thread: Australian Bush Fires
14/01/2020 04:47:33

New Zealand has provided Wallabies in the past to help out their inbreeding problems. They are around the Rotorua area, and are a wild population with little predators. Maybe more will be sent latter in the year.

Thread: Making a superglue chuck adapter for brass wheel
26/12/2019 18:46:17

Super glue to hold thin parts has been around for a very long time, it was used in industry in 1982 when I started my apprenticeship. We made the mandrel from similar material to the part being made. we put the mandrel and part into the tempering oven set at 120c . the part seperated, and the mandrels soaked in acetone to clean off the glue and start again. So we had brass, steel and AL mandrels. Sometimes the mandrel was skimmed , depending on the setup. When cylindrical grinding, or surface grinding, it was important to have a fresh dressed sharp wheel that did not have too much width. The part needed to be cut as cool as possible.

I remember when we had some thin parts being made from Delrin, and it did not glue at all. So be careful when using the cyano holding method.

Neil

Thread: Lathe lighting
07/12/2019 19:14:57

At the back of the lathe is a little cabinet to put tools whatever on, and also is a splash guard of sorts.

I put in 2 rows of led strip , and after install , added a curved down piece, to keep the bright light out of my eyes. This gives very good light at the back side of the lathe and gets quite a lot of light down a bore to a certain extent. The led is covered with a plastic difuser. It keeps oil and chips off the strip and makes a more uniform looking light. I chose 4k led strip. 5k seemed too blue of a light for me. I also add some led strip light , directly above the lathe centre line, and one strip above , inline with the front edge of the lathe bed. So the over head strip pairs, are only about 60mm apart. The extra set was added, as the centre line light did not illuminate as well as I hoped for. Maybe if I had a higher density strip would have been better. The strip does produce some heat , so the next lot will be on the purpose made Ali extrusions, that come with a range of diffusers to select from. There is such a wide choice these days of lumins per meter as well for the led strip that is available as well. With mine it was ordered from over seas, and that was a mistake, as I had no idea of how many lumins per meter I really needed to have a good light spread. I was only looking at initial dollars , not the real technical stuff, that I would have got if I went to a local led specialist who would have solved a lot of issues, and in reality , was not that much more expensive, and I would not have waited 8 weeks for it to arrive.

Thread: Reamer size questions
02/12/2019 17:46:03

You can make a lap, and lap the od of the reamer smaller to get it to the diameter that you require. This works very well with machine/chucking reamers. Lapping a hand reamer does not work so well however.

Neil

Thread: Lathe boring tool - top rake?
19/11/2019 08:55:45

There are positive rake insert ranges, usually for Aluminium and plastics. They work well on Mild Steel and softer steels.

Thread: Undrilling a hole in brass?
18/11/2019 21:37:52

Another option would have been to have made a rivot. Made from the same material is almost impossible to see as well after being peened in place.

Thread: heat-treated S2 steel alloy - machining
10/11/2019 18:05:12

You can turn hardened S2 with ceramic turning inserts. Dry cutting is about 90m/min surface speed or 900rpm.

Depth of cut with a 0.4mm radius tool is 0.2mm so 0.4mm on diameter max depth, and a feed rate of 0.06mm per rev, or 2 thou per rev. So a very fine feedrate.

Seco make series TH1000 grade insert, in a few geometries , these will also cut hardened steel, but at 25 to 50 m/min, so 1/2 to 1/4 the surface speed of the ceramic inserts.

The above inserts are available to the TNMG16 tool holders, the triangle 6 edges, negative holders.

Neil

Thread: HAS ANYONE MADE A SINE BAR ?
10/11/2019 10:04:56

It is nice if it is a nominal number for the centre distance to the rollers or roller to centre in a sine table. But the important part is knowing what that centre distance actually is, then it will be as accurate as possible. Having support side arms to aid in keeping it's correct position is a really good idea. Then the gauge blocks don't need to be kept in place. Of course there are many way's to setting the height for sine tables and sine bars.

Neil

Thread: Thread gauge
29/10/2019 18:37:21

Is that with a sharp pointed tool Jason. eg 2 inch with 4 tpi thread, from touch on the outside diameter, the minor will become 1.680 inches diameter using a 55 deg included angle tool?

Neil

Thread: Hand or Machine Reamers?
04/10/2019 21:34:03

Hand reamers have their place, like any other tool. The advantage of most hand reamers is that the taper is very useful in some situations where you may want a slightly tapered hole, or a tapered start to a hole. You may want to have a slightly oversized portion, and hand reamers will do this , as most hand reamers are in the 0.015mm to 0.02mm over the nominal reamer size at the very back of the reamer, depending on the tolerance range of the hand reamer being purchased.

I lap hand reamers down, to make special undersized reamers for press fit holes. The front tapered section is not touched. By undersized , it is only in the -0.02mm to -0.03mm to make a permanent press fit for pins.

Neil

Edited By Neil Lickfold on 04/10/2019 21:35:30

Thread: cutter slippage using ER series collets
30/09/2019 08:48:17
Posted by JasonB on 29/09/2019 19:45:13:

But what if you can use two hands on the one lever while the holder is in a bench fixture and get your weight behind it?

Yeah I would think that it would be tighter. But in the machine, using 2 levers I think is the better way to tighten the ER collets.

29/09/2019 19:37:37
Posted by Bandersnatch on 28/09/2019 22:57:24:
Posted by Neil Lickfold on 28/09/2019 21:52:47:

Using a pair of tools to tighten the collet nut is a zero torque arrangement and you can get a lot higher closing pressure instead of using just 1 tool and locking the spindle or 1 tool and a bench holder.

You'd need to explain that further for me.

So when you have a spanner holding the tool body, and a spanner holding the nut, as you bring the two tools together , there is no twisting moment on the spindle. As you bring both hands together, you can get them a lot tighter than just trying to pull on 1 lever. Mechanics do this all the time on fittings. The same in reverse, you an pull the two levers together to undo very tight fittings.

28/09/2019 21:52:47

It is very important for the cutter body, to have the full length of engagement in the collet itself. If the cutter is 3/4 of the way in the collet body, there is a high probability of it walking out on a big cut for sure . The thinner wall collets require the full length absolutely. It is for this reason that I have different collet sets, with the smaller series collets for holding the smaller cutters. Cutters with a 4mm shank or smaller I use the ER11 set. For 10mm to 5mm I use the ER16 set and for over 10mm use the ER32 set or ER40. Hanging onto a cutter with less than 1.5 diameters is never a good idea , so then you are better off buying a longer series cutter.

Using a pair of tools to tighten the collet nut is a zero torque arrangement and you can get a lot higher closing pressure instead of using just 1 tool and locking the spindle or 1 tool and a bench holder.

Neil

Thread: Chuck
26/09/2019 08:37:32

Buying precision collets saves a lot down the line. I suggest buying the highest precision collet you can afford at the time. Then buy more as you need them. Having cutters run better than .01mm every time is important and does make the cutters last longer. Also it means you have confidence is setting up a part and know it is concentric within the collets accuracy. I bought some AAA from China collets that are better than 0.005mm but not 0.002mm though.

Even though they seem expensive , precision collets really are time savers in the long run.

Neil

Thread: Myford vfd
24/09/2019 06:19:38

What I like best about the VFD and 3 phase motor on my myford is the use of a microswitch for the stop of the lathe when thread cutting. Especially when cutting internal stuff. I know some run it backwards and then feed out, but feeding in knowing that is is going to stop within 0.1mm every time is just great . I have breaking and soft start settings. I put a 3/4 kw motor on my myford about 1hp approx. I just wish I had done it many years earlier. It is smoother running and quieter over all. The smother running shows up in the improved surface finish of parts.

Not cheap , that is true, but well worth it in my view.

Neil

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