Seal Installation

SEAL ASSEMBLY

Careful fitting and assembling of the seals will assist in preventing seal failure. The following check list is advisable

 

• Ensure all metal parts are clean and free from

 

• Check that the seal housing is free of sharp edges and

 

• Where seals are to pass over threads, undercuts, some form of protective sleeve should be used.

 

• Ensure that the seal is the correct type, part number, and size as that

 

• When fitting single-acting seals particularly make certain that the pressure side of the seal is installed

 

• Check that lead in chamfers

 

• Oil the seal and surrounding metal components before

 

• Certain seal types may require appropriate fitting tools to assist in damage free

 

Composite Seal Installation

Composite Seals can be assembled easily onto one piece pistons and into internal grooves. The material will stretch, deform and compress to allow assembly and will return to its original dimension after a period of time. If this period is unacceptable the ring can be reverted to its original size immediately by exerting a force opposite to that used to assemble in the first instance. This reversal of strain can be carried out many times with no deterioration of the material properties.

 

Assembly can be carried out in many ways and we show some suggestions for tools to facilitate the simplest assembly. It is recommended that the tools should be made from plastic material (POM, PA, P.V.C., etc.) to reduce the risk of any damage to the seal.

Piston Seal Assembly

Specified Tolerances:

Nominal Sizes inch		SHAFTS (outside diameters) units 0.001 inch									BORES (inside diameters) units 0.001 inch
over	to	e9	f8	f9	h8	h9	h10	h11	js10	js11	H8	H9	H10	H11	Js11
0.04	0.12	-0.6	-0.3	-0.3	0	0	0	0	+0.8	+1.3	+0.6	+1.0	+1.6	+2.5	+1.3
		-1.6	-0.9	-1.2	-0.6	-1.0	-1.6	-2.5	-0.8	-1.3	0	0	0	0	-1.3
0.12	0.24	-0.8	-0.4	-0.4	0	0	0	0	+0.9	+1.5	+0.7	+1.2	+1.8	+3.0	+1.5
		-2.0	-1.1	-1.6	-0.7	-1.2	-1.8	-3.0	-0.9	-1.5	0	0	0	0	-1.5
0.24	0.40	-1.0	-0.5	-0.5	0	0	0	0	+1.1	+1.8	+0.9	+1.4	+2.2	+3.5	+1.8
		-2.4	-1.4	-1.9	-0.9	-1.4	-2.2	-3.5	-1.1	-1.8	0	0	0	0	-1.8
0.40	0.71	-1.2	-0.6	-0.6	0	0	0	0	+1.4	+2.0	+1.0	+1.6	+2.8	+4.0	+2.0
		-2.8	-1.6	-2.3	-1.0	-1.6	-2.8	-4.0	-1.4	-2.0	0	0	0	0	-2.0
0.71	1.19	-1.6	-0.8	-0.8	0	0	0	0	+1.8	+2.5	+1.2	+2.0	+3.5	+5.0	+2.5
		-3.6	-2.0	-2.8	-1.2	-2.0	-3.5	-5.0	-1.8	-2.5	0	0	0	0	-2.5
1.19	1.97	-2.0	-1.0	-1.0	0	0	0	0	+2.0	+3.0	+1.6	+2.5	+4.0	+6.0	+3.0
		-4.5	-2.6	-3.4	-1.6	-2.5	-4.0	-6.0	-2.0	-3.0	0	0	0	0	-3.0
1.97	3.15	-2.5	-1.2	-1.2	0	0	0	0	+2.3	+3.5	+1.8	+3.0	+4.5	+7.0	+3.5
		-5.5	-3.0	-4.1	-1.8	-3.0	-4.5	-7.0	-2.3	-3.5	0	0	0	0	-3.5
3.15	4.73	-3.0	-1.4	-1.4	0	0	0	0	+2.5	+4.5	+2.2	+3.5	+5.0	+9.0	+4.5
		-6.5	-3.6	-4.8	-2.2	-3.5	-5.0	-9.0	-2.5	-4.5	0	0	0	0	-4.5
4.73	7.09	-3.5	-1.6	-1.6	0	0	0	0	+3.0	+5.0	+2.5	+4.0	+6.0	+10.0	+5.0
		-7.5	-4.1	-5.6	-2.5	-4.0	-6.0	-10.0	-3.0	-5.0	0	0	0	0	-5.0
7.09	9.85	-4.0	-2.0	-2.0	0	0	0	0	+3.5	+6.0	+2.8	+4.5	+7.0	+12.0	+6.0
		-8.5	-4.8	-6.5	-2.8	-4.5	-7.0	-12.0	-3.5	-6.0	0	0	0	0	-6.0
9.85	12.41	-4.5	-2.2	-2.2	0	0	0	0	+4.0	+6.0	+3.0	+5.0	+8.0	+12.0	+6.0
		-9.5	-5.2	-7.3	-3.0	-5.0	-8.0	-12.0	-4.0	-6.0	0	0	0	0	-6.0

Tolerances   extracted   from   BS1916   with   kind   permission   of   British   Standards   Institution.

Nominal Sizes mm		SHAFTS (outside diameters) units 0.001 mm									BORES (inside diameters) units 0.001 mm
ov- er	to	e9	f8	f9	h8	h9	h10	h11	js10	js11	H8	H9	H10	H11	Js11
1.6	3	-14 -39	-6 -20	-6 -31	0 -14	0 -25	0 -40	0 -60	+20 -20	+30 -30	+14 0	+25 0	+40 0	+60 0	+30 -30
3	6	-20 -50	-10 -28	-10 -40	0 -18	0 -30	0 -48	0 -75	+24 -24	+37.5 -37.5	+18 0	+30 0	+48 0	+75 0	+37.5 -37.5
6	10	-25 -61	-13 -35	-13 -49	0 -22	0 -36	0 -58	0 -90	+29 -29	+45 -45	+22 0	+36 0	+58 0	+90 0	+45 -45
10	18	-32 -75	-16 -43	-16 -59	0 -27	0 -43	0 -70	0 -110	+35 -35	+55 -55	+27 0	+43 0	+70 0	+110 0	+55 -55
18	30	-40 -92	-20 -53	-20 -72	0 -33	0 -52	0 -84	0 -130	+42 -42	+65 -65	+33 0	+52 0	+84 0	+130 0	+65 -65
30	50	-50 -112	-25 -64	-25 -87	0 -39	0 -62	0 -100	0 -160	+50 -50	+80 -80	+39 0	+62 0	+100 0	+160 0	+80 -80
50	80	-60 -134	-30 -76	-30 -104	0 -46	0 -74	0 -120	0 -190	+60 -60	+95 -95	+46 0	+74 0	+120 0	+190 0	+95 -95
80	120	-72 -159	-36 -90	-36 -123	0 -54	0 -87	0 -140	0 -220	+70 -70	+110 -110	+54 0	+87 0	+140 0	+220 0	+110 -110
120	180	-85 -185	-43 -106	-43 -143	0 -63	0 -100	0 -160	0 -250	+80 -80	+125 -125	+63 0	+100 0	+160 0	+250 0	+125 -125
180	250	-100 -215	-50 -122	-50 -165	0 -72	0 -115	0 -185	0 -290	+92 -92	+145 -145	+72 0	+115 0	+185 0	+290 0	+145 -145
250	315	-110 -240	-56 -137	-56 -186	0 -81	0 -130	0 -210	0 -320	+105 -105	+160 -160	+81 0	+130 0	+210 0	+320 0	+160 -160
315	400	-125 -265	-62 -151	-62 -212	0 -89	0 -140	0 -230	0 -360	+115 -115	+180 -180	+89 0	+140 0	+230 0	+360 0	+180 -180