PER CURIAM.
In May, 1978, Clarence Haines was severely injured while operating a table saw at the Coast Guard base carpentry shop in St. Louis, Missouri. The table saw was manufactured by Powermatic Houdaille, Inc. The injury occurred while Haines was using the saw alone without the blade guard in place. Haines was guiding a board through the saw with his hands several inches from the blade when the wood lifted up and kicked back, throwing his left hand into the blade. As a result of the accident, Haines became partially disabled and left the Coast Guard as a Temporary Disabled Retiree.
Haines filed suit in state court against Powermatic charging that the saw’s defective design created an unreasonable risk of harm. The saw was allegedly defective because the blade guard had to be removed for certain operations of the saw, and because there was no warning given against the danger of operating the saw without the guard. The case was removed to federal district court. The parties consented to trial before a United States Magistrate and agreed that any appeal would be to this court pursuant to 28 U.S.C. § 636(c). The case was submitted to a jury which returned a verdict in favor of Powermatic. Haines appeals on the grounds that the magistrate erred in (1) failing to grant his motion for a mistrial following the court’s comment regarding plaintiff’s previous knowledge of the blade guard, and (2) instructing the jury as to plaintiff’s voluntary and unreasonable exposure to a known risk and the absence of defendant’s duty to warn. We affirm.
I.
The parties agree that the magistrate, in sustaining an objection before the jury, erroneously stated that: “As a matter of fact, the plaintiff in this cáse has already indicated his knowledge of the existence of the guard.” Haines had not so testified. The appellant promptly objected and moved for a mistrial. The magistrate denied the motion but immediately instructed the jury that the court’s comments were not evidence to be considered by the jury. The magistrate gave similar cautionary instructions at the beginning of the trial, at another time during the trial, and at the close of all the evidence.
Federal trial judges are accorded the right to comment upon the evidence to the jury. They may not, however, prejudice or mislead the jury. E. g., Ah Lou Koa v. American Export Isbrandsten Lines, Inc., 513 F.2d 261, 263 (2d Cir. 1975); Greener v. Green, 460 F.2d 1279, 1280-1281 (3rd Cir. 1972). While cautionary instructions will not always cure erroneous judicial comments, here the magistrate’s repeated cautionary instructions made clear that the court’s statements were not evidence and that the jury — not the court — was to make the ultimate assessment of facts. See Skogen v. Dow Chemical Co., 375 F.2d 692, 703 (8th Cir. 1967). We have carefully re