Metal Lathe

General Info

Harrison L6 Mk1, 3ph supply has now been fitted (not pictured)

The Hackspace has a Harrison L6 Mk1 metalworking lathe. Metalworking lathes are dangerous machines and you should not attempt to use it without an induction. Details on the induction process are TBC.

Specification and Leading Dimensions

Standard Model vs With Profiling Equipment

Specification / Dimension	Standard Model	With Profiling Equipment
Swing over bed	12" (305 mm) or 16" (410 mm)	12" (305 mm), 16" (410 mm) or 20" (510 mm)
Swing over cross slide	7¼" (184 mm)	7¼" (184 mm)
Swing in gap	20¾" (527 mm)	20¾" (527 mm)
Width of bed	7⅜" (187 mm)	7⅜" (187 mm)
Length of bed	4'6", 6'0" or 7'6" (1372 mm, 1829 mm or 2286 mm)	4'6", 6'0" or 7'6" (1372 mm, 1829 mm or 2286 mm)
Admit between centres	24" or 40" (610 mm or 1016 mm)	24" or 40" (610 mm or 1016 mm)
Distance between slide and face of plate screwed on spindle	19⅝" (498 mm)	19⅝" (498 mm)
Range of copy turning with chucks (external)	5½" – 7¼" (140 – 184 mm)	5½" – 7¼" (140 – 184 mm)
Range of copy turning with chucks (internal)	4½" – 4¾" (114 – 121 mm)	4½" – 4¾" (114 – 121 mm)
Range of profiling (external turning)	–	14" – 20" (356 – 510 mm)
Range of profiling (internal turning)	–	2" – 7" (51 – 178 mm)
Range of profiling (copy turning)	–	3" – 9" (76 – 229 mm)
Cross slide feed (profiling)	–	4½" (114 mm)
Longitudinal feed (copy turning)	–	20" (508 mm)
Compound slide travel	4" (102 mm)	4" (102 mm)
Cross slide travel	7¾" (197 mm)	7¾" (197 mm)
Tailstock set over (both directions)	1⅛" (29 mm)	1⅛" (29 mm)
Tailstock barrel travel	6" (152 mm)	6" (152 mm)
Tailstock barrel diameter	1¾" (44 mm)	1¾" (44 mm)
Spindle bore	1⅜" (35 mm)	1⅜" (35 mm)
Spindle nose	1⅞" x 8 t.p.i.	1⅞" x 8 t.p.i.
Spindle speed (direct belt)	34 – 490 r.p.m.	34 – 490 r.p.m.
Spindle speed (back gear)	4 – 57 r.p.m.	4 – 57 r.p.m.
Motor horsepower	1 or 1½ h.p. motor	1 or 1½ h.p. motor (standard), or 2 h.p. hydraulic pump motor
Drive	Vee belt	Vee belt
Width of space occupied	28¾" (730 mm)	28¾" (730 mm)
Height over bed	35" (889 mm)	35" (889 mm)

Notes

• Dimensions given in inches with metric conversions.
• Ranges of profiling apply only to models fitted with profiling equipment.

Level 1 training

This entire section was lifted from https://wiki.london.hackspace.org.uk/view/Lathe_Training

Level 1 training consists of a single course which is designed to take a complete beginner through all the essential skills needed to produce basic but functional parts on a lathe. It will also act as a good refresher/ competency test for those who already have experience from elsewhere. Members must start by watching the recommended videos listed below, to learn as much of the theory in advance – although no substitute for practical experience, machining is a skill where a firm grasp of both is essential and there will not be time to cover both in the induction session. We will start the training session by re-capping the theory and going over the key safety concerns before we move onto taking our first cuts with an external turning tool, facing and turning. We will then introduce the tailstock and explain its role in supporting long workpieces and use it to drill a hole. Finally, we will demonstrate how to measure the work and use the DRO to work to dimensions. The course will end with a semi-supervised test part which you will make, putting the skills you have learned into practice. Note that level 1 only considers use of a 3-jaw chuck, level 2 training is required for other work holding methods.

Beginner users should watch the following training videos before booking a session:

(Lathe Theory)

(Tool Bits)

(Facing)

(Tail Support)

(Turning)

(Chatter)

(Turning to a Shoulder)

(Drilling)

(Surface Finish)

(Choosing Materials)

(Feeds and Speeds)

(Additional Video on Surface Finish)

Note - most of the videos above are from the Blondihacks 'lathe skills' video series. This whole series is filled with useful content and we would fully recommend watching the rest, although this is not compulsary for a level 1 training session.

One of London hackspaces lathe trainers has provided notes here: File:Toby's Lathe Training Notes r03.pdf. Other trainers will do something similar, but might not follow this exact plan

Manual

There is a full paper manual and digital copy at the space.

Hackspace specific information

Activity to take place by the lathe.

PPE

Ensure all lose items including hair are tied back or stuck down with appropriate tape. Inspect this regularly as the main danger with lathe use is lose items being dragged into the lathe. It is advised that users wear safety glasses or one of the safety face shields provided or provide their own. New spares are in the social space cupboard, a donation is appreciated. Gloves should not be worn.

Induction

See above notes.

An induction is required for use of this machine and the videos listed above should be watched prior to requesting an induction.

• Ensuring the area is clear and tidy
• Method of working - including (and to put no finer point on it, do NOT leave the chuck key in the chuck)
• Safe use of tool - Demonstrate safe operation (on/off) of machinery, use of safety features including those which have been added, wearing appropriate PPE.
• Importance of non lone working
• Basic use of lathe and DRO
• use of accessories
• use of cutting fluids and the ventilation system
• use of toolpost and bringing your own cutting pieces.
• cleanup

Prior to commencement of lathe work

Ensure the area is free of obstructions (slips trips and falls) and is clean, tidy and does not have loose objects in and around the lathe working area. Ensure the machine is clear of swarf and use gloves when removing swarf only. Ensure the machine is off during this operation. Remove gloves prior to operation.

Completion of lathe work

Cleanup work area and return all tools/accessories prior to completion of session.

Thread Cutting Ranges

Range	T.P.I.	Top Shaft	Intermediate Shaft	Bottom Shaft	G.B. Lever Position
Standard	4 to 60	30	120 / 60	60	As Gearbox Chart
Fine	8 to 120	30	120 / 60	120	4 to 60*
Coarse	2 to 15	60	120	30	4 to 60 †
Special Threads	11½	40	120 / 60	115	4
	27	40	115	60	36

Notes:

* G. Box T.P.I. Position = (T.P.I. Required ÷ 2)

- † G. Box T.P.I. Position = (T.P.I. Required × 4)

Complete Range of T.P.I.

Coarse (Additional)	2	2¼	2½	2¾	3	3¼	3½	3¾
Standard	4	4½	5	5½	6	6½	7	7½
	8	9	10	11	12	13	14	15
	16	18	19	20	22	24	26	28
	30	32	36	38	40	44	48	52
	56	60
Fine (Additional)	64	72	76	80	88	96	104	112
	120
Special	11½	27

Metric Screwcutting Chart

Metric Pitch (mm)	Top Shaft	Intermediate Shaft	Bottom Shaft	T.P.I. Position
0.5	30	127–120	48	60
0.75	30	127–120	48	40
1.0	30	127–120	48	30
1.25	30	127–120	48	24
1.5	30	127–120	48	20
1.75	28	127–120	48	16
2.0	30	127–120	48	15
2.5	30	127–120	48	12
3.0	30	127–120	48	10
3.5	28	127–120	48	8
4.0	30	127–120	48	7½
4.5	36	127–120	48	8
5.0	30	127–120	48	6
6.0	30	127–120	48	5
7.0	28	127–120	48	4

Warnings and Notes

• When cutting threads coarser than ½″ pitch, it is advisable to engage the half nuts with the spindle stationary, then engage the clutch.
• The use of the lowest spindle speed is essential.
• The maximum pitch that can be cut on a centre lathe is determined by the diameter and depth of cut required. The recommended maximum helix for roughing is 8° and a light cut up to 10°–12°.
• The cutting of a coarse thread should only be carried out by a skilled operator who will appreciate the limitations imposed by the conditions, which will vary according to the type of material, thread, and depth of cut, etc.

Maintenance of this page

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