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LIT-118

Adjusting The Handpiece To Fit You

With the locking ring slightly loose, you are able to turn the handpiece body and knob 

independently. Position the Quick Change holder with the graver “point” down. Rotate 

the knob until the hose position is comfortable, then tighten the locking ring.
You can also extend the length of the handpiece a little by unscrewing the knob and 

body even more. 

NOTE:

 By extending the length you may notice a loss of power 

depending on the type of work you are doing.

How To Attach A New Hose

Loosen the locking ring. Remove the knob from the handpiece. Remove the hose by 

cutting it off close to the knob. With a small punch, push the hose / brass fitting back 

into the knob body. Remove the brass fitting (#004-409) from the hose. Feed the new 

air hose through the hole in the knob (Fig. 1). Insert the brass fitting into the end of 

the new hose, making sure it is fully seated. 

If needed, lubricate the fitting first to help it slip into the hose easier. Then apply a 

small amount of water or oil around the outside end of the hose next to the brass 

fitting and pull the hose back (Fig. 2) into the knob until you see the tip of the brass 

fitting protrude through the side of the knob. This must be an air tight fit, so you will 

have to pull somewhat hard (a few pounds of pressure, at least).

Create A Flat On The Bottom (If Desired)

If you choose to put a flat on the knob, use the handpiece first to find out where the 

hose “exit” is most comfortable for you. 

Note warranty information to the right.

 

Maintenance

Keeping the 901 clean on the inside. Problems will occur if oil or moisture gets 

into the handpiece, especially on the piston. If you notice a loss of power or 

erratic performance, first check if the 

receiver (chuck) is tight in the handpiece 

body

. Using a cresent wrench or pliers with a graver inserted in the QC Holder, 

gently tighten receiver clockwise (Fig. 3) If erratic performance continues, then 

disassemble and clean the handpiece. To disassemble the handpiece, use the 

crescent wrench or pliers to grip the graver (Fig. 3) and turn it counterclockwise to 

loosen the chuck retainer. 

Continued on page 2.

GRS 901 Handpiece 

InsTRUCTIons

For GraverMach & GraverMax SC 

#004-901

Standard Spring

Fine Spring

Normal Operating Range

18-22 psi (1.2-1.5 bar) / 1400 - 3400 spm

12-15 psi (0.8-1.0 bar) / 1600 - 3600 spm

Recommended Initial Setting

19 psi (1.3 bar) / 2700 spm

13 psi (0.9 bar) / 3000 spm

PSI: Pounds per Square Inch  •  Bar: Unit of Measurement  •  SPM: Strokes Per Minute 

LoCKInG RInG 

Loosen first

Fig. 1

Lubricate end slightly 
with water or a 

small

 

amount of oil.

Fig. 2

IMPORTANT

Too much material removal will 

result in damaged* knob (PART 
#004-404).

*Any damage to knob from 

creating a flat is NOT covered 

by warranty.

*METAL REMOVAL PAST MINIMUM DIMENSION WILL DAMAGE KNOB

LOOSEN

TURn CoUnTERCLoCKWIsE

TIGHTEN

TURn CLoCKWIsE

Fig. 3 

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