Quick & Easy way to draw and get dimensions of an existing part

Quick and easy way to draw and get dimensions for duplicating or producing new parts with out CAD. The graph sheet in this case is with 1mm resolution. 

Place the part on the graph sheet and trace it along. 

Lathe tips and tricks

Sheet metal gauge size chart

Gauge (or gage) sizes are numbers that indicate the thickness of a piece of sheet metal, with a higher number referring to a thinner sheet. The equivalent thicknesses differ for each gauge size standard, which were developed based on the weight of the sheet for a given material. The Manufacturers' Standard Gage provides the thicknesses for standard steel, galvanized steel, and stainless steel. The chart below can be used to determine the equivalent sheet thickness, in inches or millimeters, for a gauge number from the selected gauge size standard. The weight per unit area of the sheet can also be seen in pounds per square foot and kilograms per square meter.

	Thickness		Weight Per Area
Gauge	in	mm	lb/ft²	kg/m²
3	0.2391	6.073	9.754	47.624
4	0.2242	5.695	9.146	44.656
5	0.2092	5.314	8.534	41.668
6	0.1943	4.935	7.927	38.701
7	0.1793	4.554	7.315	35.713
8	0.1644	4.176	6.707	32.745
9	0.1495	3.797	6.099	29.777
10	0.1345	3.416	5.487	26.790
11	0.1196	3.038	4.879	23.822
12	0.1046	2.657	4.267	20.834
13	0.0897	2.278	3.659	17.866
14	0.0747	1.897	3.047	14.879
15	0.0673	1.709	2.746	13.405
16	0.0598	1.519	2.440	11.911
17	0.0538	1.367	2.195	10.716
18	0.0478	1.214	1.950	9.521
19	0.0418	1.062	1.705	8.326
20	0.0359	0.912	1.465	7.151
21	0.0329	0.836	1.342	6.553
22	0.0299	0.759	1.220	5.955
23	0.0269	0.683	1.097	5.358
24	0.0239	0.607	0.975	4.760
25	0.0209	0.531	0.853	4.163
26	0.0179	0.455	0.730	3.565
27	0.0164	0.417	0.669	3.267
28	0.0149	0.378	0.608	2.968
29	0.0135	0.343	0.551	2.689
30	0.0120	0.305	0.490	2.390
31	0.0105	0.267	0.428	2.091
32	0.0097	0.246	0.396	1.932
33	0.0090	0.229	0.367	1.793
34	0.0082	0.208	0.335	1.633
35	0.0075	0.191	0.306	1.494
36	0.0067	0.170	0.273	1.335
37	0.0064	0.163	0.261	1.275
38	0.0060	0.152	0.245	1.195

change gear claculation

Charts with standard gear set for metric mini-lathes: 20, 20, 30, 35, 40, 40, 45, 50, 50, 60, 60, 80, 80.

When for B and C gears ANY is shown on tables, it means that  B and C gears are only necessary as a idler gear. On  these cases, use for B and C a pair of gears with the same teeth number and a suitable size to mesh with A and D.

To calculate change-gears combination for threading on any lathe you can use the following formula:  TPI = (B/A) x (D/C) x leadscrew pitch

Metric threading on lathes with metric 1.5mm pitch leadscrew

Simplified chart

For the mini-lathe banjo and with the original gear set. 

MM / PITCH	A	B	C	D	ERROR %
0.25	20	60	40	80	0.0000
0.3	40	50	20	80	0.0000
0.35	20	50	35	60	0.0000
0.4	20	60	40	50	0.0000
0.45	20	60	45	50	0.0000
0.5	40	60	30	60	0.0000
0.6	20	60	60	50	0.0000
0.7	35	60	40	50	0.0000
0.75	20	60	60	40	0.0000
0.8	40	60	40	50	0.0000
1	60	45	30	60	0.0000
1.25	40	60	50	40	0.0000
1.5	40	60	60	40	0.0000
1.75	35	60	60	30	0.0000
2	60	50	50	45	0.0000
2.5	50	60	60	30	0.0000
3	40	80	80	20	0.0000
3.5	35	60	80	20	0.0000
4	80	60	60	30	0.0000
4.5	60	80	80	20	0.0000
5	50	30	80	40	0.0000

Extended charts

Many of these combinations don't fit the mini-lathe banjo, though can be used with other banjo styles. 

MM / PITCH	A	B	C	D	ERROR %	TPI
0.25	20	45	30	80	0.0000	101.600
0.25	20	60	40	80	0.0000	101.600
0.25	20	80	40	60	0.0000	101.600
0.25	30	45	20	80	0.0000	101.600
0.25	40	60	20	80	0.0000	101.600

MM / PITCH	A	B	C	D	ERROR %	TPI
0.3	20	50	30	60	0.0000	84.667
0.3	20	50	40	80	0.0000	84.667
0.3	20	60	30	50	0.0000	84.667
0.3	20	80	40	50	0.0000	84.667
0.3	30	50	20	60	0.0000	84.667
0,3	30	60	20	50	0.0000	84.667
0,3	40	50	20	80	0.0000	84.667

MM / PITCH	A	B	C	D	ERROR %	TPI
0.35	20	50	35	60	0.0000	72.571
0.35	20	60	35	50	0.0000	72.571
0.35	35	50	20	60	0.0000	72.571
0.35	35	60	20	50	0.0000	72.571

MM / PITCH	A	B	C	D	ERROR %	TPI
0.4	20	50	40	60	0.0000	63.500
0.4	20	60	40	50	0.0000	63.500
0.4	40	50	20	60	0.0000	63.500
0.4	40	60	20	50	0.0000	63.500

MM / PITCH	A	B	C	D	ERROR %	TPI
0.45	20	50	45	60	0.0000	56.444
0.45	20	50	60	80	0.0000	56.444
0.45	20	60	45	50	0.0000	56.444
0.45	20	80	60	50	0.0000	56.444
0.45	30	50	40	80	0.0000	56.444
0.45	30	80	40	50	0.0000	56.444
0.45	40	50	30	80	0.0000	56.444
0.45	45	50	20	60	0.0000	56.444
0.45	45	60	20	50	0.0000	56.444
0.45	60	50	20	80	0.0000	56.444

MM / PITCH	A	B	C	D	ERROR %	TPI
0.5	20	ANY	ANY	60	0.0000	50.800
0.5	40	60	30	60	0.0000	50.800

MM / PITCH	A	B	C	D	ERROR %	TPI
0.6	20	ANY	ANY	50	0.0000	42.333

MM / PITCH	A	B	C	D	ERROR %	TPI
0.7	30	45	35	50	0.0000	36.286
0.7	30	50	35	45	0.0000	36.286
0.7	35	45	30	50	0.0000	36.286
0.7	35	50	30	45	0.0000	36.286
0.7	35	50	40	60	0.0000	36.286
0.7	35	60	40	50	0.0000	36.286
0.7	40	50	35	60	0.0000	36.286
0.7	40	60	35	50	0.0000	36.286

MM / PITCH	A	B	C	D	ERROR %	TPI
0.75	20	ANY	ANY	40	0.0000	33.867
0.75	30	ANY	ANY	60	0.0000	33.867
0.75	40	ANY	ANY	80	0.0000	33.867

MM / PITCH	A	B	C	D	ERROR %	TPI
0.8	20	45	60	50	0.0000	31.750
0.8	20	50	60	45	0.0000	31.750
0.8	20	50	80	60	0.0000	31.750
0.8	20	60	80	50	0.0000	31.750
0.8	30	45	40	50	0.0000	31.750
0.8	30	50	40	45	0.0000	31.750
0.8	40	45	30	50	0.0000	31.750
0.8	40	50	30	45	0.0000	31.750
0.8	40	50	40	60	0.0000	31.750
0.8	40	60	40	50	0.0000	31.750
0.8	60	45	20	50	0.0000	31.750
0.8	60	50	20	45	0.0000	31.750
0.8	80	50	20	60	0.0000	31.750
0.8	80	60	20	50	0.0000	31.750

MM / PITCH	A	B	C	D	ERROR %	TPI
1	20	ANY	ANY	30	0.0000	25.400
1	30	ANY	ANY	45	0.0000	25.400
1	40	ANY	ANY	60	0.0000	25.400
1	60	45	30	60	0.0000	25.400

MM / PITCH	A	B	C	D	ERROR %	TPI
1.25	50	ANY	ANY	60	0.0000	20.320
1.25	40	60	50	40	0.0000	20.320

MM / PITCH	A	B	C	D	ERROR %	TPI
1.5	20	ANY	ANY	20	0.0000	16.933
1.5	40	ANY	ANY	40	0.0000	16.933
1.5	80	ANY	ANY	80	0.0000	16.933

MM / PITCH	A	B	C	D	ERROR %	TPI
1.75	35	ANY	ANY	30	0.0000	14.514

MM / PITCH	A	B	C	D	ERROR %	TPI
2	40	ANY	ANY	30	0.0000	12.700
2	60	ANY	ANY	45	0.0000	12.700
2	80	ANY	ANY	60	0.0000	12.700

MM / PITCH	A	B	C	D	ERROR %	TPI
2.5	50	ANY	ANY	30	0.0000	10.160

MM / PITCH	A	B	C	D	ERROR %	TPI
3	40	ANY	ANY	20	0.0000	8.467
3	60	ANY	ANY	30	0.0000	8.467
3	80	ANY	ANY	40	0.0000	8.467

MM / PITCH	A	B	C	D	ERROR %	TPI
3.5	35	20	60	45	0.0000	7.257
3.5	35	20	80	60	0.0000	7.257
3.5	35	30	80	40	0.0000	7.257
3.5	35	40	80	30	0.0000	7.257
3.5	35	45	60	20	0.0000	7.257
3.5	35	60	80	20	0.0000	7.257
3.5	60	20	35	45	0.0000	7.257
3.5	60	45	35	20	0.0000	7.257
3.5	80	20	35	60	0.0000	7.257
3.5	80	30	35	40	0.0000	7.257
3.5	80	40	35	30	0.0000	7.257

MM / PITCH	A	B	C	D	ERROR %	TPI
4	80	ANY	ANY	30	0.0000	6.350

MM / PITCH	A	B	C	D	ERROR %	TPI
4.5	60	ANY	ANY	20	0.0000	5.644

MM / PITCH	A	B	C	D	ERROR %	TPI
5	50	20	60	45	0.0000	5.080
5	50	20	80	60	0.0000	5.080
5	50	30	80	40	0.0000	5.080
5	50	40	80	30	0.0000	5.080
5	50	45	60	20	0.0000	5.080
5	50	60	80	20	0.0000	5.080
5	60	20	50	45	0.0000	5.080
5	60	45	50	20	0.0000	5.080
5	80	20	50	60	0.0000	5.080
5	80	30	50	40	0.0000	5.080
5	80	40	50	30	0.0000	5.080
5	80	60	50	20	0.0000	5.080

Source :  http://www.toolsandmods.com/change-gears-charts-for-metric-threading.html