Here is a list of all the postings DC31k has made in our forums. Click on a thread name to jump to the thread.
Thread: turning a large diameter |
05/09/2023 12:35:20 |
OK, it is not turning and it will not produce a circular arc, but you would get very close with a boring head in a mill and angling the head of the mill. When the head is perpendicular to the table, it produces an infinite radius (flat surface). When it is parallel to the table, it produces a circular radius equal to the swept diameter of the cutter. So at some angle between those two it will produce an elliptical arc which will be very close to the 39" circular radius needed. Replace the single point tool of the boring head with an abrasive wheel and the ground finish becomes a possibility. --- There is also the method used in woodworking of calculating the sagitta of the arc, nailing two straight pieces together at an angle and swinging them between the two end points of the chord. The vertex sweeps out the arc. |
Thread: What are they? |
04/09/2023 17:22:25 |
I have seen very similar, but with the boss on the outside of the curve, in a lever-operated lathe spindle-mounted collet chuck. The closing ring, to which the lever is attached, remains stationary and only moves forward or backward when operating the lever. The bronze slippers run in a groove in the part of the closing ring that rotates with the chuck. I must stress that the ones I have seen are inside out compared to the ones you show, so the above could be highly misleading. Edit: part number 7 in this drawing: https://www.model-engineer.co.uk/sites/7/images/member_albums/91402/893454.jpg Edited By DC31k on 04/09/2023 17:25:12 |
Thread: Beavermill Mk2 - HELP - Missing Small Gear |
31/08/2023 11:23:28 |
Do you have a manual for the machine? There is an exploded diagram of the variable speed head therein. The gear is part number 101 P1326. 32DP, 10t https://www.modelsport.co.uk/product/traxxas-pinion-gear-10-t-32-p-steel-set-screw-437089 |
Thread: Oil equivalents for Gargoil (Gargoyle) DTE 797 |
30/08/2023 19:50:22 |
'Gargoyle' looks to have origniated with the Vacuum Oil Company: https://en.wikipedia.org/wiki/Vacuum_Oil_Company subsequently owned by Mobil (not Texaco). However, in here (page 18): http://www.gannonoils.co.uk/images/stories/Texaco-Equivalents-list.pdf Texaco list their own equivalent to Mobil DTE 797 as 32 weight hydraulic oil, as suggested above. |
Thread: Harrison L5 |
30/08/2023 19:39:24 |
Posted by Derek cottiss on 30/08/2023 19:23:00:
.it has an imperial norton box but does changing the change wheels alter the tpi on the box ? Of course it does. You can prove it to yourself. Hold a piece of broomstick in the chuck and use a marker pen in the toolpost to draw the thread onto the wood. Alter the changewheels upstream of the gearbox and see what effect it has. Please advise which of the manuals you have and the page number that is relevant to your machine. Do the gears you have on the machine right now match what is there? |
Thread: A combinatorial problem. |
30/08/2023 19:11:22 |
Posted by Rod Renshaw on 30/08/2023 14:50:55:
Can anything similar be done for sets of angle blocks Yes. Write down the list of blocks of whose possibilities you would like to see. For a 15 degree block, you would list it twice as +15 and -15. The possibility of selecting it twice would take care of itself as it would lead to a zero result. You would have to write a little logic into the program at the results printing stage so that it did not try to tell you that it could make -45 degrees from -30 and -15 as well as +45 degrees from the same blocks. |
30/08/2023 08:10:00 |
Posted by Robin Graham on 30/08/2023 00:22:58:
The whole thing started because I wanted to check my micrometers (0-150mm) It might be worth sniffing aroung the NPL's literature on metrology. If you are to check a micrometer over, say, a 1" range, there are a number of preferred measurements at which to make those checks. I do not recall the exact details, but in principle, the 'best' way is _not_ using regular intervals. Please see here just as an example of a commercial one: https://mqs.co.uk/mm1-8-micrometer-check-set-with-stand-8-pieces-inch.html Micrometers have been around a long time and standardised methods have been developed for their calibration. It would be wise to be aware of them as that gives you a rationale for any deviations you make from that method. |
Thread: Harrison L5 |
30/08/2023 07:58:59 |
Harrison L5 manual here (one at the top of the page, one at the bottom): http://vintagemachinery.org/mfgindex/detail.aspx?id=3031&tab=3 I am reasonably sure it is not what you want, but am including it just in case. It is the screwcutting chart for the 'basic' L5 model: https://www.ebay.co.uk/itm/364215982969 |
Thread: Lathe in a Box |
27/08/2023 15:17:50 |
Posted by Andy_H on 27/08/2023 14:13:08:
That seems very easy to fabricate but I reckon it needs to be truly concentric to the pulley and with a even internal surface to avoid inducing annoying vibration. Looks like a rubber wrapped brass boss attached to the motor shaft - a bit like a over-sized version of pinch roller found in cassette players! Any suggestions on how to make this... Make the motor 'pulley' first. Any old bit of hardwood would do. Drill and tap so it can be secured to the motor shaft. Shape roughly circular with hand tools. Mount on motor. Switch on. Apply sandpaper glued to a flat board until the pulley is round and smooth. Glue sandpaper, rough side out to finished pulley. Switch on and apply to rough finished plywood disk on countershaft. Rotate countershaft slowly. Once plywood is finished round, concentric and smooth, remove sandpaper from motor pulley and replace with rubber. A smart person would size the motor pulley so something like a slice of mountain bike inner tube fits it snugly. |
Thread: Indexing jig |
27/08/2023 15:08:18 |
Posted by JasonB on 27/08/2023 13:40:27:
I've seen dimples next to holes with different colour infill to help locate common combinations That might be a good 3D printing job - different coloured, different arc length masks for the unused holes (so for 6 divisions in a 36 plate, each single mask from the blue set of six would cover five holes). It would give you a little flexibility of clocking over a dimple in a fixed position. Simple solution might be 35 individual hole bungs. |
27/08/2023 13:24:17 |
With the 36 holes (10 degree spacing), you might be able to come up with a vernier plunger/indexing pin to achieve one degree resolution. Have a look at the standard 5C spin indexer for inspiration. When you are in the supermarket, have you ever reflected on how the 'ten items or less' checkout is misusing the English language? Edited By DC31k on 27/08/2023 13:26:22 |
Thread: Forum Platform Changes - PLEASE READ |
27/08/2023 09:56:52 |
Posted by SillyOldDuffer on 26/08/2023 20:12:44:
All I've done is correct the source code
If you are road testing the new forum, could you have a look to see if it has something like a [code][/code] tag that we could put around things we wish to be displayed as effectively unformatted, monospaced text. It would help with computer code of any language and maybe if someone wants to post G-code. It would also help if someone wants to post tabulated information. |
Thread: Draper GD16/16c pillar drill drive belts |
27/08/2023 09:42:02 |
Posted by jon man on 27/08/2023 09:17:00:
I downloaded the Draper manual but does not have belt sizes listed, i'll try find somewhere that sells 23" belts. Even if it does not list the size, does it show the belts as one part number or two separate part numbers? If it is a single part number, the belts will be identical. |
Thread: Wanted. A supplier of imperial R8 arbour. |
27/08/2023 09:05:07 |
If the slightly longer version described above is not to your requirements, a shorter version is available from Chronos: https://www.chronos.ltd.uk/product/r8-stub-slitting-saw-arbors/ |
Thread: Help identify collet chuck |
26/08/2023 17:22:34 |
Posted by Howard Lewis on 26/08/2023 17:00:00:
INT tapers are all 3 .75" / foot. Our youngest member recently received an award for makling an INT40 taper fitting to carry ER40 collets, One can only hope that at no point during his making of it did he confer with you on specifications. Please advise how 3.75" per foot can work out to be 7 in 24. |
26/08/2023 09:31:35 |
Posted by peak4 on 25/08/2023 19:44:59:
The company is 'LAIP'. https://www.laip.es/en |
Thread: Metric Fine Threads |
26/08/2023 09:24:34 |
Posted by JasonB on 26/08/2023 06:50:44:
How does that work?
It doesn't. The partial profile inserts are not 'topping' inserts. Every major insert manufacturer spends a lot of time and money producing literature describing their products. The literature stresses that for partial profile inserts, the stock diameter is critical. See bottom of page 10. https://usercontent.azureedge.net/Content/UserContent/Documents/034353.pdf |
Thread: A combinatorial problem. |
26/08/2023 07:09:52 |
Your example is incorrect. You have eight possibilities. You can choose zero blocks. The total is the sum of the corresponding line in Pascal's triangle. I think your problem can be described as the sum of 'N choose R' (or 'R choose N', I forget which way the terms are used). So you do 3 choose 0 plus 3 choose 1 plus 3 choose 2 plus 3 choose 3 to arrive at your total. In Python, it is easy as there is an itertools module that does the combinations and permutations maths for you. You might have to consider uniqueness in your calculations - different combinations of blocks could add up to the same total. Again, in Python, you put your total into a set, which cannot contain duplicate entries. If you want to display systematically, you store the total and block choices in a standard list. For 30, the list item would be (30, 10, 20); for 35, the list would be (35, 20, 25). Then sort the list by total and print out the list. When the numbers get big (like an 81 piece imperial gauge block set), the time taken for the calculations is excessive. Edited By DC31k on 26/08/2023 07:11:32 |
Thread: Help identify collet chuck |
25/08/2023 19:24:19 |
Looks like an OZ collet. Lots of somewhat dubious supposition above. The easiest way to confirm, rather than to speculate, is to measure the drawbar thread: if it is M12 or 1/2", it will be 30 taper. If it is 5/8" or M16, it will be 40 taper. You can also measure the fat end of the taper: 1.25" for 30 taper, 1.75" for 40 taper. |
Thread: expunging a block |
24/08/2023 21:14:07 |
Try 'purge'. https://nanocad.com/learning/online-help/purging-of-document/ Same idea, different word. |
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